Date: Wed, 28 Apr 2021 13:29:36 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: pgsql-hackers@lists.postgresql.org
Subject: strange case of "if ((a & b))"
Message-ID: <20210428182936.GE27406@telsasoft.com>
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These look strange to me - the inner parens don't do anything.
I wouldn't write it with 2x parens for the same reason I wouldn't write it with
8x parens.

diff --git a/contrib/amcheck/verify_heapam.c b/contrib/amcheck/verify_heapam.c
index 9f159eb3db..3bbc13c443 100644
--- a/contrib/amcheck/verify_heapam.c
+++ b/contrib/amcheck/verify_heapam.c
@@ -693,7 +693,7 @@ check_tuple_header(HeapCheckContext *ctx)
 			report_corruption(ctx,
 							  psprintf("tuple data should begin at byte %u, but actually begins at byte %u (1 attribute, has nulls)",
 									   expected_hoff, ctx->tuphdr->t_hoff));
-		else if ((infomask & HEAP_HASNULL))
+		else if ((infomask & HEAP_HASNULL) != 0)
 			report_corruption(ctx,
 							  psprintf("tuple data should begin at byte %u, but actually begins at byte %u (%u attributes, has nulls)",
 									   expected_hoff, ctx->tuphdr->t_hoff, ctx->natts));
diff --git a/contrib/ltree/ltree_io.c b/contrib/ltree/ltree_io.c
index 15115cb29f..0dd2838f8b 100644
--- a/contrib/ltree/ltree_io.c
+++ b/contrib/ltree/ltree_io.c
@@ -661,17 +661,17 @@ deparse_lquery(const lquery *in)
 				}
 				memcpy(ptr, curtlevel->name, curtlevel->len);
 				ptr += curtlevel->len;
-				if ((curtlevel->flag & LVAR_SUBLEXEME))
+				if ((curtlevel->flag & LVAR_SUBLEXEME) != 0)
 				{
 					*ptr = '%';
 					ptr++;
 				}
-				if ((curtlevel->flag & LVAR_INCASE))
+				if ((curtlevel->flag & LVAR_INCASE) != 0)
 				{
 					*ptr = '@';
 					ptr++;
 				}
-				if ((curtlevel->flag & LVAR_ANYEND))
+				if ((curtlevel->flag & LVAR_ANYEND) != 0)
 				{
 					*ptr = '*';
 					ptr++;
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 13396eb7f2..f5a4db5c57 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -2107,7 +2107,8 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
 			vmstatus = visibilitymap_get_status(relation,
 								 BufferGetBlockNumber(buffer), &vmbuffer);
 
-		if ((starting_with_empty_page || vmstatus & VISIBILITYMAP_ALL_FROZEN))
+		if (starting_with_empty_page ||
+				(vmstatus & VISIBILITYMAP_ALL_FROZEN) != 0)
 			all_frozen_set = true;
 	}
 
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 441445927e..28fdd2943b 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -2417,7 +2417,7 @@ PrepareTransaction(void)
 	 * cases, such as a temp table created and dropped all within the
 	 * transaction.  That seems to require much more bookkeeping though.
 	 */
-	if ((MyXactFlags & XACT_FLAGS_ACCESSEDTEMPNAMESPACE))
+	if ((MyXactFlags & XACT_FLAGS_ACCESSEDTEMPNAMESPACE) != 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot PREPARE a transaction that has operated on temporary objects")));
@@ -5530,7 +5530,7 @@ XactLogCommitRecord(TimestampTz commit_time,
 		xl_xinfo.xinfo |= XACT_COMPLETION_UPDATE_RELCACHE_FILE;
 	if (forceSyncCommit)
 		xl_xinfo.xinfo |= XACT_COMPLETION_FORCE_SYNC_COMMIT;
-	if ((xactflags & XACT_FLAGS_ACQUIREDACCESSEXCLUSIVELOCK))
+	if ((xactflags & XACT_FLAGS_ACQUIREDACCESSEXCLUSIVELOCK) != 0)
 		xl_xinfo.xinfo |= XACT_XINFO_HAS_AE_LOCKS;
 
 	/*
@@ -5681,7 +5681,7 @@ XactLogAbortRecord(TimestampTz abort_time,
 
 	xlrec.xact_time = abort_time;
 
-	if ((xactflags & XACT_FLAGS_ACQUIREDACCESSEXCLUSIVELOCK))
+	if ((xactflags & XACT_FLAGS_ACQUIREDACCESSEXCLUSIVELOCK) != 0)
 		xl_xinfo.xinfo |= XACT_XINFO_HAS_AE_LOCKS;
 
 	if (nsubxacts > 0)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 8e717ada28..f341e6d143 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -16029,7 +16029,7 @@ PreCommit_on_commit_actions(void)
 				 * relations, we can skip truncating ON COMMIT DELETE ROWS
 				 * tables, as they must still be empty.
 				 */
-				if ((MyXactFlags & XACT_FLAGS_ACCESSEDTEMPNAMESPACE))
+				if ((MyXactFlags & XACT_FLAGS_ACCESSEDTEMPNAMESPACE) != 0)
 					oids_to_truncate = lappend_oid(oids_to_truncate, oc->relid);
 				break;
 			case ONCOMMIT_DROP:
diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c
index ff3dcc7b18..fe825c6ede 100644
--- a/src/backend/nodes/nodeFuncs.c
+++ b/src/backend/nodes/nodeFuncs.c
@@ -2390,7 +2390,7 @@ query_tree_walker(Query *query,
 	 * don't contain actual expressions. However they do contain OIDs which
 	 * may be needed by dependency walkers etc.
 	 */
-	if ((flags & QTW_EXAMINE_SORTGROUP))
+	if ((flags & QTW_EXAMINE_SORTGROUP) != 0)
 	{
 		if (walker((Node *) query->groupClause, context))
 			return true;
@@ -3328,7 +3328,7 @@ query_tree_mutator(Query *query,
 	 * may be of interest to some mutators.
 	 */
 
-	if ((flags & QTW_EXAMINE_SORTGROUP))
+	if ((flags & QTW_EXAMINE_SORTGROUP) != 0)
 	{
 		MUTATE(query->groupClause, query->groupClause, List *);
 		MUTATE(query->windowClause, query->windowClause, List *);
diff --git a/src/backend/replication/logical/decode.c b/src/backend/replication/logical/decode.c
index 7924581cdc..62baf48f8e 100644
--- a/src/backend/replication/logical/decode.c
+++ b/src/backend/replication/logical/decode.c
@@ -337,7 +337,7 @@ DecodeXactOp(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
 					ReorderBufferXidSetCatalogChanges(ctx->reorder, xid,
 													  buf->origptr);
 				}
-				else if ((!ctx->fast_forward))
+				else if ((!ctx->fast_forward) != 0)
 					ReorderBufferImmediateInvalidation(ctx->reorder,
 													   invals->nmsgs,
 													   invals->msgs);