From 33634107d72866cb85544f274a217ad592f61fe0 Mon Sep 17 00:00:00 2001
From: Zsolt Parragi <zsolt.parragi@percona.com>
Date: Sun, 15 Mar 2026 11:22:00 +0000
Subject: [PATCH 2/4] gen_guc_tables: reject type-inappropriate fields in
 guc_parameters.dat

Detect when a GUC entry has fields that don't apply to its type, such
as "min" or "max" on a bool or string, or "options" on an int.  These
would be silently ignored, likely indicating a copy-paste mistake.

The existing required_by_type structure is replaced with a single
type_specific_fields hash that drives both the required-field and
inappropriate-field checks.
---
 src/backend/utils/misc/gen_guc_tables.pl | 32 ++++++++++++++++++------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/src/backend/utils/misc/gen_guc_tables.pl b/src/backend/utils/misc/gen_guc_tables.pl
index ba2e6f001f1..b1c1b7afc6c 100644
--- a/src/backend/utils/misc/gen_guc_tables.pl
+++ b/src/backend/utils/misc/gen_guc_tables.pl
@@ -45,12 +45,12 @@ sub validate_guc_entry
 	my @required_common =
 	  qw(name type context group short_desc variable boot_val);
 
-	my %required_by_type = (
-		int => [qw(min max)],
-		real => [qw(min max)],
-		enum => [qw(options)],
-		bool => [],      # no extra required fields
-		string => [],    # no extra required fields
+	my %type_specific_fields = (
+		int => { map { $_ => 1 } qw(min max) },
+		real => { map { $_ => 1 } qw(min max) },
+		enum => { map { $_ => 1 } qw(options) },
+		bool => {},
+		string => {},
 	);
 
 	# All fields recognized by the generator.  "line_number" is injected
@@ -83,7 +83,7 @@ sub validate_guc_entry
 		}
 	}
 
-	unless (exists $required_by_type{ $entry->{type} })
+	unless (exists $type_specific_fields{ $entry->{type} })
 	{
 		die sprintf(
 			qq{%s:%d: error: entry "%s" has unrecognized GUC type "%s"\n},
@@ -91,7 +91,9 @@ sub validate_guc_entry
 			$entry->{name}, $entry->{type} // '<unknown>');
 	}
 
-	for my $f (@{ $required_by_type{ $entry->{type} } })
+	my $fields_for_type = $type_specific_fields{ $entry->{type} };
+
+	for my $f (sort keys %$fields_for_type)
 	{
 		unless (defined $entry->{$f})
 		{
@@ -101,6 +103,20 @@ sub validate_guc_entry
 				$entry->{type}, $f);
 		}
 	}
+
+	my %all_type_specific;
+	$all_type_specific{$_} = 1
+	  for map { keys %$_ } values %type_specific_fields;
+	for my $f (sort keys %$entry)
+	{
+		if ($all_type_specific{$f} && !$fields_for_type->{$f})
+		{
+			die sprintf(
+				qq{%s:%d: error: entry "%s" of type "%s" must not have field "%s"\n},
+				$input_fname, $entry->{line_number}, $entry->{name},
+				$entry->{type}, $f);
+		}
+	}
 }
 
 # Print GUC table.
-- 
2.43.0