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[PATCH v50 2/8] Rename cluster.c/h -> repack.c/h
266+ messages / 2 participants
[nested] [flat]

* [PATCH v50 2/8] Rename cluster.c/h -> repack.c/h
@ 2026-03-31 16:55 Álvaro Herrera <alvherre@kurilemu.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Álvaro Herrera @ 2026-03-31 16:55 UTC (permalink / raw)

---
 src/backend/commands/Makefile                |  2 +-
 src/backend/commands/matview.c               |  2 +-
 src/backend/commands/meson.build             |  2 +-
 src/backend/commands/{cluster.c => repack.c} |  6 +++---
 src/backend/commands/tablecmds.c             |  2 +-
 src/backend/commands/vacuum.c                |  6 +++---
 src/backend/storage/ipc/procsignal.c         |  1 +
 src/backend/tcop/postgres.c                  |  1 +
 src/backend/tcop/utility.c                   |  2 +-
 src/include/commands/{cluster.h => repack.h} | 12 ++++++------
 10 files changed, 19 insertions(+), 17 deletions(-)
 rename src/backend/commands/{cluster.c => repack.c} (99%)
 rename src/include/commands/{cluster.h => repack.h} (90%)

diff --git a/src/backend/commands/Makefile b/src/backend/commands/Makefile
index c10fdba2bbb..fe1bba3a9b9 100644
--- a/src/backend/commands/Makefile
+++ b/src/backend/commands/Makefile
@@ -18,7 +18,6 @@ OBJS = \
 	amcmds.o \
 	analyze.o \
 	async.o \
-	cluster.o \
 	collationcmds.o \
 	comment.o \
 	constraint.o \
@@ -51,6 +50,7 @@ OBJS = \
 	proclang.o \
 	propgraphcmds.o \
 	publicationcmds.o \
+	repack.o \
 	schemacmds.o \
 	seclabel.o \
 	sequence.o \
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index d3be8939011..5db4fe75dce 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -24,8 +24,8 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_opclass.h"
-#include "commands/cluster.h"
 #include "commands/matview.h"
+#include "commands/repack.h"
 #include "commands/tablecmds.h"
 #include "commands/tablespace.h"
 #include "executor/executor.h"
diff --git a/src/backend/commands/meson.build b/src/backend/commands/meson.build
index 90c7e37a429..f624aae74af 100644
--- a/src/backend/commands/meson.build
+++ b/src/backend/commands/meson.build
@@ -6,7 +6,6 @@ backend_sources += files(
   'amcmds.c',
   'analyze.c',
   'async.c',
-  'cluster.c',
   'collationcmds.c',
   'comment.c',
   'constraint.c',
@@ -39,6 +38,7 @@ backend_sources += files(
   'proclang.c',
   'propgraphcmds.c',
   'publicationcmds.c',
+  'repack.c',
   'schemacmds.c',
   'seclabel.c',
   'sequence.c',
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/repack.c
similarity index 99%
rename from src/backend/commands/cluster.c
rename to src/backend/commands/repack.c
index f241e18b153..20f0a572236 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/repack.c
@@ -1,6 +1,6 @@
 /*-------------------------------------------------------------------------
  *
- * cluster.c
+ * repack.c
  *    REPACK a table; formerly known as CLUSTER.  VACUUM FULL also uses
  *    parts of this code.
  *
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  src/backend/commands/cluster.c
+ *	  src/backend/commands/repack.c
  *
  *-------------------------------------------------------------------------
  */
@@ -33,9 +33,9 @@
 #include "catalog/pg_am.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/toasting.h"
-#include "commands/cluster.h"
 #include "commands/defrem.h"
 #include "commands/progress.h"
+#include "commands/repack.h"
 #include "commands/tablecmds.h"
 #include "commands/vacuum.h"
 #include "miscadmin.h"
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 0ce2e81f9c2..e2882a50b3b 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -57,10 +57,10 @@
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
 #include "catalog/toasting.h"
-#include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
 #include "commands/event_trigger.h"
+#include "commands/repack.h"
 #include "commands/sequence.h"
 #include "commands/tablecmds.h"
 #include "commands/tablespace.h"
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 0ed363d1c85..b179b62b5c8 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -9,7 +9,7 @@
  *
  * VACUUM for heap AM is implemented in vacuumlazy.c, parallel vacuum in
  * vacuumparallel.c, ANALYZE in analyze.c, and VACUUM FULL is a variant of
- * CLUSTER, handled in cluster.c.
+ * REPACK, handled in repack.c.
  *
  *
  * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
@@ -38,9 +38,9 @@
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
 #include "commands/async.h"
-#include "commands/cluster.h"
 #include "commands/defrem.h"
 #include "commands/progress.h"
+#include "commands/repack.h"
 #include "commands/vacuum.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
@@ -2293,7 +2293,7 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			if ((params.options & VACOPT_VERBOSE) != 0)
 				cluster_params.options |= CLUOPT_VERBOSE;
 
-			/* VACUUM FULL is a variant of REPACK; see cluster.c */
+			/* VACUUM FULL is a variant of REPACK; see repack.c */
 			cluster_rel(REPACK_COMMAND_VACUUMFULL, rel, InvalidOid,
 						&cluster_params);
 			/* cluster_rel closes the relation, but keeps lock */
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 7e017c8d53b..7cef6e43661 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -19,6 +19,7 @@
 
 #include "access/parallel.h"
 #include "commands/async.h"
+#include "commands/repack.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "port/pg_bitutils.h"
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 10be60011ad..9fbaa5c00f0 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -39,6 +39,7 @@
 #include "commands/event_trigger.h"
 #include "commands/explain_state.h"
 #include "commands/prepare.h"
+#include "commands/repack.h"
 #include "common/pg_prng.h"
 #include "jit/jit.h"
 #include "libpq/libpq.h"
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 2b609bfc824..5f8c766c4be 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -26,7 +26,6 @@
 #include "catalog/toasting.h"
 #include "commands/alter.h"
 #include "commands/async.h"
-#include "commands/cluster.h"
 #include "commands/collationcmds.h"
 #include "commands/comment.h"
 #include "commands/conversioncmds.h"
@@ -46,6 +45,7 @@
 #include "commands/proclang.h"
 #include "commands/propgraphcmds.h"
 #include "commands/publicationcmds.h"
+#include "commands/repack.h"
 #include "commands/schemacmds.h"
 #include "commands/seclabel.h"
 #include "commands/sequence.h"
diff --git a/src/include/commands/cluster.h b/src/include/commands/repack.h
similarity index 90%
rename from src/include/commands/cluster.h
rename to src/include/commands/repack.h
index d6b62c747e8..85061158b0c 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/repack.h
@@ -1,17 +1,17 @@
 /*-------------------------------------------------------------------------
  *
- * cluster.h
- *	  header file for postgres cluster command stuff
+ * repack.h
+ *	  header file for the REPACK command
  *
  * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994-5, Regents of the University of California
  *
- * src/include/commands/cluster.h
+ * src/include/commands/repack.h
  *
  *-------------------------------------------------------------------------
  */
-#ifndef CLUSTER_H
-#define CLUSTER_H
+#ifndef REPACK_H
+#define REPACK_H
 
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -52,4 +52,4 @@ extern void finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
 							 MultiXactId cutoffMulti,
 							 char newrelpersistence);
 
-#endif							/* CLUSTER_H */
+#endif							/* REPACK_H */
-- 
2.47.3


--brnevsqjnuzpyok4
Content-Type: text/x-diff; charset=utf-8
Content-Disposition: attachment;
	filename="v50-0003-Add-CONCURRENTLY-option-to-REPACK-command.patch"



^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread

* [PATCH v2] meson: Fix ccache issues when using precompiled headers with gcc
@ 2026-07-15 19:27 Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 266+ messages in thread

From: Andres Freund @ 2026-07-15 19:27 UTC (permalink / raw)

Unfortunately the combination of gcc, precompiled headers, ccache and meson
currently is not safe without further options. The dependencies emitted by gcc
are insufficient to trigger rebuilds when headers "below" the precompiled
headers are changed. Whether that's a ccache, gcc or meson bug is
debatable. Luckily gcc's -fpch-deps option fixes the issue.

This problem occasionally leads to build failures, e.g. if only c.h,
postgres.h or pg_config_manual.h change. That's e.g. the case when creating a
new major version branch.

Discussion: https://postgr.es/m/CAN55FZ0tqR6Xz%3DiVFLc1BBoLOEHU775ARhcGYwggHA3XLA%3DoQg%40mail.gmail.com
Discussion: https://postgr.es/m/CA+hUKG+s7Yvt0PUnSQUEjCjysV-7-51n9B1h468Le3VJi0x4ZQ@mail.gmail.com
Discussion: https://postgr.es/m/phsrssp75npoyalqsolcd7fmnmlbzbmquc2p7w7mqjlw7432jk@bzskz3luyjvb
Discussion: https://github.com/ccache/ccache/issues/1686
Backpatch-through: 16, where meson support was added
---
 meson.build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/meson.build b/meson.build
index 61b5681851e..f4cde249242 100644
--- a/meson.build
+++ b/meson.build
@@ -2185,6 +2185,12 @@ common_functional_flags = [
   # Disable optimizations that assume no overflow; needed for gcc 4.3+
   '-fwrapv',
   '-fexcess-precision=standard',
+  # Without -fpch-deps gcc emits dependencies that are insufficient for ccache
+  # to trigger a rebuild when the precompiled header changes. We could make
+  # this depend on using gcc and precompiled headers being enabled, but that's
+  # probably not worth it.  See also
+  # https://github.com/ccache/ccache/issues/1686
+  '-fpch-deps',
 ]
 
 cflags += cc.get_supported_arguments(common_functional_flags)
-- 
2.54.0.450.g9ac3f193c0


--lrkjybh77g2jf2vx--





^ permalink  raw  reply  [nested|flat] 266+ messages in thread