Date: Thu, 24 Jun 2021 21:31:11 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: strange case of "if ((a & b))"
Message-ID: <20210625023110.GI29179@telsasoft.com>
References: <20210428182936.GE27406@telsasoft.com>
 <2896014.1619635209@sss.pgh.pa.us>
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On Wed, Apr 28, 2021 at 02:40:09PM -0400, Tom Lane wrote:
> Justin Pryzby <pryzby@telsasoft.com> writes:
> > 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.
> 
> Agreed, but shouldn't we just drop the excess parens rather than
> doubling down on useless notation?

I believe I got the impression from Michael that there was a style preference
to write != 0.

0002 is a bonus patch I found in my typos branch.  I will hold onto it for
later if nobody wants to deal with it.

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From 2534ff46830ab505a6a2079a1b6c0f8a1e9b2b8b Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 28 Apr 2021 14:12:49 -0500
Subject: [PATCH 1/2] Avoid double parens

git grep -l '\<if (([^(]*))' '*.c'
---
 contrib/amcheck/verify_heapam.c          | 6 +++---
 contrib/ltree/ltree_io.c                 | 6 +++---
 src/backend/access/transam/xact.c        | 6 +++---
 src/backend/commands/tablecmds.c         | 2 +-
 src/backend/nodes/nodeFuncs.c            | 4 ++--
 src/backend/replication/logical/decode.c | 2 +-
 6 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/contrib/amcheck/verify_heapam.c b/contrib/amcheck/verify_heapam.c
index a3caee7cdd..cd275bd45d 100644
--- a/contrib/amcheck/verify_heapam.c
+++ b/contrib/amcheck/verify_heapam.c
@@ -389,13 +389,13 @@ verify_heapam(PG_FUNCTION_ARGS)
 													   &vmbuffer);
 			if (skip_option == SKIP_PAGES_ALL_FROZEN)
 			{
-				if ((mapbits & VISIBILITYMAP_ALL_FROZEN) != 0)
+				if (mapbits & VISIBILITYMAP_ALL_FROZEN)
 					continue;
 			}
 
 			if (skip_option == SKIP_PAGES_ALL_VISIBLE)
 			{
-				if ((mapbits & VISIBILITYMAP_ALL_VISIBLE) != 0)
+				if (mapbits & VISIBILITYMAP_ALL_VISIBLE)
 					continue;
 			}
 		}
@@ -692,7 +692,7 @@ 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)
 			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..b75f35d5b5 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)
 				{
 					*ptr = '%';
 					ptr++;
 				}
-				if ((curtlevel->flag & LVAR_INCASE))
+				if (curtlevel->flag & LVAR_INCASE)
 				{
 					*ptr = '@';
 					ptr++;
 				}
-				if ((curtlevel->flag & LVAR_ANYEND))
+				if (curtlevel->flag & LVAR_ANYEND)
 				{
 					*ptr = '*';
 					ptr++;
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index da8a460722..9c13a7c589 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -2452,7 +2452,7 @@ 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)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot PREPARE a transaction that has operated on temporary objects")));
@@ -5565,7 +5565,7 @@ 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)
 		xl_xinfo.xinfo |= XACT_XINFO_HAS_AE_LOCKS;
 
 	/*
@@ -5716,7 +5716,7 @@ XactLogAbortRecord(TimestampTz abort_time,
 
 	xlrec.xact_time = abort_time;
 
-	if ((xactflags & XACT_FLAGS_ACQUIREDACCESSEXCLUSIVELOCK))
+	if (xactflags & XACT_FLAGS_ACQUIREDACCESSEXCLUSIVELOCK)
 		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 4e23c7fce5..39180999fd 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -16171,7 +16171,7 @@ 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)
 					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..ae3364dfdc 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)
 	{
 		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)
 	{
 		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 453efc51e1..34a36b22f8 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)
 					ReorderBufferImmediateInvalidation(ctx->reorder,
 													   invals->nmsgs,
 													   invals->msgs);
-- 
2.17.0


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From 16773708a7ab2c995fa3d7e1bba1b3626468a8d0 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sat, 8 May 2021 08:12:46 -0500
Subject: [PATCH 2/2] tablefunc.c: Fix comment

Mentioned at: https://www.postgresql.org/message-id/CAJRYxuKmMkgHFKjuYPxThdT5Mjg%2Bg-nH5szYbS8UoVsQXzd95A%40mail.gmail.com
---
 contrib/tablefunc/tablefunc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/contrib/tablefunc/tablefunc.c b/contrib/tablefunc/tablefunc.c
index 779bd4415e..52b272f298 100644
--- a/contrib/tablefunc/tablefunc.c
+++ b/contrib/tablefunc/tablefunc.c
@@ -1480,7 +1480,7 @@ validateConnectbyTupleDesc(TupleDesc td, bool show_branch, bool show_serial)
 						"fifth column must be type %s",
 						format_type_be(INT4OID))));
 
-	/* check that the type of the fifth column is INT4 */
+	/* check that the type of the fourth column is INT4 */
 	if (!show_branch && show_serial &&
 		TupleDescAttr(td, 3)->atttypid != INT4OID)
 		ereport(ERROR,
-- 
2.17.0


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