From f4c24d5b87dbbbd1af5740ec12a5d42bd8f1349d Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Fri, 3 Oct 2025 08:27:18 +0200
Subject: [PATCH v2 2/5] Change config_generic.vartype to be initialized at
 compile time

Previously, this was initialized at run time so that it did not have
to be maintained by hand in guc_tables.c, but since that table is now
generated anyway, we might as well generate this bit as well.

Discussion: https://www.postgresql.org/message-id/flat/8fdfb91e-60fb-44fa-8df6-f5dea47353c9@eisentraut.org
---
 src/backend/utils/misc/gen_guc_tables.pl |  1 +
 src/backend/utils/misc/guc.c             | 28 +-----------------------
 src/include/utils/guc_tables.h           |  2 +-
 3 files changed, 3 insertions(+), 28 deletions(-)

diff --git a/src/backend/utils/misc/gen_guc_tables.pl b/src/backend/utils/misc/gen_guc_tables.pl
index a48a9ebd0eb..b187259bf1e 100644
--- a/src/backend/utils/misc/gen_guc_tables.pl
+++ b/src/backend/utils/misc/gen_guc_tables.pl
@@ -68,6 +68,7 @@ sub print_one_table
 		  if $entry->{long_desc};
 		printf $ofh "\t\t\t.flags = %s,\n", $entry->{flags}
 		  if $entry->{flags};
+		printf $ofh "\t\t\t.vartype = %s,\n", ('PGC_' . uc($type));
 		print $ofh "\t\t},\n";
 		printf $ofh "\t\t.variable = &%s,\n", $entry->{variable};
 		printf $ofh "\t\t.boot_val = %s,\n", $entry->{boot_val};
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index a64427ac979..a82286cc98a 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -890,48 +890,22 @@ build_guc_variables(void)
 											 ALLOCSET_DEFAULT_SIZES);
 
 	/*
-	 * Count all the built-in variables, and set their vartypes correctly.
+	 * Count all the built-in variables.
 	 */
 	for (int i = 0; ConfigureNamesBool[i].gen.name; i++)
-	{
-		struct config_bool *conf = &ConfigureNamesBool[i];
-
-		/* Rather than requiring vartype to be filled in by hand, do this: */
-		conf->gen.vartype = PGC_BOOL;
 		num_vars++;
-	}
 
 	for (int i = 0; ConfigureNamesInt[i].gen.name; i++)
-	{
-		struct config_int *conf = &ConfigureNamesInt[i];
-
-		conf->gen.vartype = PGC_INT;
 		num_vars++;
-	}
 
 	for (int i = 0; ConfigureNamesReal[i].gen.name; i++)
-	{
-		struct config_real *conf = &ConfigureNamesReal[i];
-
-		conf->gen.vartype = PGC_REAL;
 		num_vars++;
-	}
 
 	for (int i = 0; ConfigureNamesString[i].gen.name; i++)
-	{
-		struct config_string *conf = &ConfigureNamesString[i];
-
-		conf->gen.vartype = PGC_STRING;
 		num_vars++;
-	}
 
 	for (int i = 0; ConfigureNamesEnum[i].gen.name; i++)
-	{
-		struct config_enum *conf = &ConfigureNamesEnum[i];
-
-		conf->gen.vartype = PGC_ENUM;
 		num_vars++;
-	}
 
 	/*
 	 * Create hash table with 20% slack
diff --git a/src/include/utils/guc_tables.h b/src/include/utils/guc_tables.h
index c5776be029b..3de3d809545 100644
--- a/src/include/utils/guc_tables.h
+++ b/src/include/utils/guc_tables.h
@@ -177,8 +177,8 @@ struct config_generic
 	const char *short_desc;		/* short desc. of this variable's purpose */
 	const char *long_desc;		/* long desc. of this variable's purpose */
 	int			flags;			/* flag bits, see guc.h */
+	enum config_type vartype;	/* type of variable */
 	/* variable fields, initialized at runtime: */
-	enum config_type vartype;	/* type of variable (set only at startup) */
 	int			status;			/* status bits, see below */
 	GucSource	source;			/* source of the current actual value */
 	GucSource	reset_source;	/* source of the reset_value */
-- 
2.51.0