Change-IO-stats-enum-loop-variables-to-ints.patch

From 34fee4a3d1d1353aa38a95b3afc2d302a5f586ff Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Mon, 27 Feb 2023 08:48:11 -0500
Subject: [PATCH v1 2/2] Change IO stats enum loop variables to ints

Per [1], using an enum as the loop variable with a macro-defined
termination condition of #_enum_values + 1 is not guaranteed to be safe
- as compilers are free to make enums as small as a char.

Some (older) compilers will notice this when building with
-Wtautological-constant-out-of-range-compare.

[1] https://www.postgresql.org/message-id/354645.1677511842%40sss.pgh.pa.us
---
 src/backend/utils/activity/pgstat_io.c | 12 ++++++------
 src/backend/utils/adt/pgstatfuncs.c    |  8 ++++----
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/backend/utils/activity/pgstat_io.c b/src/backend/utils/activity/pgstat_io.c
index c478b126fa..c4199d18c8 100644
--- a/src/backend/utils/activity/pgstat_io.c
+++ b/src/backend/utils/activity/pgstat_io.c
@@ -36,16 +36,16 @@ pgstat_bktype_io_stats_valid(PgStat_BktypeIO *backend_io,
 {
 	bool		bktype_tracked = pgstat_tracks_io_bktype(bktype);
 
-	for (IOObject io_object = 0; io_object < IOOBJECT_NUM_TYPES; io_object++)
+	for (int io_object = 0; io_object < IOOBJECT_NUM_TYPES; io_object++)
 	{
-		for (IOContext io_context = 0; io_context < IOCONTEXT_NUM_TYPES; io_context++)
+		for (int io_context = 0; io_context < IOCONTEXT_NUM_TYPES; io_context++)
 		{
 			/*
 			 * Don't bother trying to skip to the next loop iteration if
 			 * pgstat_tracks_io_object() would return false here. We still
 			 * need to validate that each counter is zero anyway.
 			 */
-			for (IOOp io_op = 0; io_op < IOOP_NUM_TYPES; io_op++)
+			for (int io_op = 0; io_op < IOOP_NUM_TYPES; io_op++)
 			{
 				/* No stats, so nothing to validate */
 				if (backend_io->data[io_object][io_context][io_op] == 0)
@@ -109,11 +109,11 @@ pgstat_flush_io(bool nowait)
 	else if (!LWLockConditionalAcquire(bktype_lock, LW_EXCLUSIVE))
 		return true;
 
-	for (IOObject io_object = 0; io_object < IOOBJECT_NUM_TYPES; io_object++)
+	for (int io_object = 0; io_object < IOOBJECT_NUM_TYPES; io_object++)
 	{
-		for (IOContext io_context = 0; io_context < IOCONTEXT_NUM_TYPES; io_context++)
+		for (int io_context = 0; io_context < IOCONTEXT_NUM_TYPES; io_context++)
 		{
-			for (IOOp io_op = 0; io_op < IOOP_NUM_TYPES; io_op++)
+			for (int io_op = 0; io_op < IOOP_NUM_TYPES; io_op++)
 				bktype_shstats->data[io_object][io_context][io_op] +=
 					PendingIOStats.data[io_object][io_context][io_op];
 		}
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 12eda4ade0..b61a12382b 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1306,7 +1306,7 @@ pg_stat_get_io(PG_FUNCTION_ARGS)
 
 	reset_time = TimestampTzGetDatum(backends_io_stats->stat_reset_timestamp);
 
-	for (BackendType bktype = 0; bktype < BACKEND_NUM_TYPES; bktype++)
+	for (int bktype = 0; bktype < BACKEND_NUM_TYPES; bktype++)
 	{
 		Datum		bktype_desc = CStringGetTextDatum(GetBackendTypeDesc(bktype));
 		PgStat_BktypeIO *bktype_stats = &backends_io_stats->stats[bktype];
@@ -1325,11 +1325,11 @@ pg_stat_get_io(PG_FUNCTION_ARGS)
 		if (!pgstat_tracks_io_bktype(bktype))
 			continue;
 
-		for (IOObject io_obj = 0; io_obj < IOOBJECT_NUM_TYPES; io_obj++)
+		for (int io_obj = 0; io_obj < IOOBJECT_NUM_TYPES; io_obj++)
 		{
 			const char *obj_name = pgstat_get_io_object_name(io_obj);
 
-			for (IOContext io_context = 0; io_context < IOCONTEXT_NUM_TYPES; io_context++)
+			for (int io_context = 0; io_context < IOCONTEXT_NUM_TYPES; io_context++)
 			{
 				const char *context_name = pgstat_get_io_context_name(io_context);
 
@@ -1357,7 +1357,7 @@ pg_stat_get_io(PG_FUNCTION_ARGS)
 				 */
 				values[IO_COL_CONVERSION] = Int64GetDatum(BLCKSZ);
 
-				for (IOOp io_op = 0; io_op < IOOP_NUM_TYPES; io_op++)
+				for (int io_op = 0; io_op < IOOP_NUM_TYPES; io_op++)
 				{
 					int			col_idx = pgstat_get_io_op_index(io_op);
 
-- 
2.37.2