From 5668cae79da67fee2eab6c5ce480fed521446680 Mon Sep 17 00:00:00 2001
From: Matthias van de Meent <boekewurm+postgres@gmail.com>
Date: Tue, 7 Apr 2026 21:21:57 +0200
Subject: [PATCH v20260407 4/4] Some check simplification/deduplication.

---
 src/backend/storage/ipc/shmem.c | 60 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 43 deletions(-)

diff --git a/src/backend/storage/ipc/shmem.c b/src/backend/storage/ipc/shmem.c
index 12de6344cac..540a51b50e5 100644
--- a/src/backend/storage/ipc/shmem.c
+++ b/src/backend/storage/ipc/shmem.c
@@ -704,49 +704,23 @@ AttachShmemIndexEntry(ShmemRequest *request, bool missing_ok)
 		return false;
 	}
 
-	/* Check that the sizes in the index match the request. */
-	if (index_entry->size != request->options->size &&
-		request->options->size != SHMEM_ATTACH_UNKNOWN_SIZE)
-	{
-		ereport(ERROR,
-				(errmsg("shared memory struct \"%s\" was created with"
-						" different size: existing %zu, requested %zu",
-						name, index_entry->size, request->options->size)));
-	}
-
-	/*
-	 * For resizable structures, also check that minimum_size and maximum_size
-	 * match. For fixed-size structures, these are derived (set to size) in
-	 * the index entry and not meaningful in the request.
-	 */
-	if (request->options->maximum_size != 0)
-	{
-		if (index_entry->minimum_size != request->options->minimum_size &&
-			request->options->minimum_size != SHMEM_ATTACH_UNKNOWN_SIZE)
-		{
-			ereport(ERROR,
-					(errmsg("shared memory struct \"%s\" was created with"
-							" different minimum_size: existing %zu, requested %zu",
-							name, index_entry->minimum_size,
-							request->options->minimum_size)));
-		}
-
-		if (index_entry->maximum_size != request->options->maximum_size &&
-			request->options->maximum_size != SHMEM_ATTACH_UNKNOWN_SIZE)
-		{
-			ereport(ERROR,
-					(errmsg("shared memory struct \"%s\" was created with"
-							" different maximum_size: existing %zu, requested %zu",
-							name, index_entry->maximum_size,
-							request->options->maximum_size)));
-		}
-	}
-	else
-	{
-		if (index_entry->minimum_size != index_entry->maximum_size)
-			elog(ERROR, "shared memory struct \"%s\" was created as resizable, but requested as fixed-size",
-				 name);
-	}
+#define CHECK_SIZE(size) \
+do { \
+	/* Check that the sizes in the index match the request. */ \
+	if (request->options->size != SHMEM_ATTACH_UNKNOWN_SIZE && \
+		index_entry->size != request->options->size) \
+	{ \
+		ereport(ERROR, \
+				(errmsg("shared memory struct \"%s\" was created with" \
+						" different %s: existing %zu, requested %zu", \
+						name, CppAsString(size), index_entry->size, \
+						request->options->size))); \
+	} \
+} while (false)
+
+	CHECK_SIZE(size);
+	CHECK_SIZE(minimum_size);
+	CHECK_SIZE(maximum_size);
 
 	/*
 	 * Re-establish the caller's pointer variable, or do other actions to
-- 
2.50.1 (Apple Git-155)