v3-0003-Avoid-duplicating-GUC-name-when-it-s-already-case.patch

From 485dd56a0a2a50f725fcc9af2d370bfa4a197c8b Mon Sep 17 00:00:00 2001
From: Jeff Davis <jeff@j-davis.com>
Date: Sun, 19 Nov 2023 13:41:49 -0800
Subject: [PATCH v3 3/5] Avoid duplicating GUC name when it's already
 case-folded.

---
 src/backend/utils/misc/guc.c   | 70 ++++++++++++++++++++++++++++------
 src/include/utils/guc_tables.h |  3 +-
 2 files changed, 60 insertions(+), 13 deletions(-)

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index b51d10dbc0..5e3b95e3f2 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -265,6 +265,7 @@ static bool call_string_check_hook(struct config_string *conf, char **newval,
 								   void **extra, GucSource source, int elevel);
 static bool call_enum_check_hook(struct config_enum *conf, int *newval,
 								 void **extra, GucSource source, int elevel);
+static bool guc_is_name_key(const char *name);
 static char * guc_name_key(int elevel, const char *name);
 
 #define SH_PREFIX		GUCHash
@@ -903,6 +904,22 @@ get_guc_variables(int *num_vars)
 }
 
 
+/*
+ * Check if name is already case-folded.
+ */
+static bool
+guc_is_name_key(const char *name)
+{
+	for(const char *p = name; *p; p++)
+	{
+		if (*p >= 'A' && *p <= 'Z')
+			return false;
+	}
+
+	return true;
+}
+
+
 /*
  * Convert to key by case folding.
  */
@@ -953,7 +970,11 @@ build_guc_variables(void)
 		/* Rather than requiring vartype to be filled in by hand, do this: */
 		conf->gen.vartype = PGC_BOOL;
 
-		conf->gen.name_key = guc_name_key(ERROR, conf->gen.name);
+		if (guc_is_name_key(conf->gen.name))
+			conf->gen.name_key = conf->gen.name;
+		else
+			conf->gen.name_key = guc_name_key(ERROR, conf->gen.name);
+
 		num_vars++;
 	}
 
@@ -963,7 +984,11 @@ build_guc_variables(void)
 
 		conf->gen.vartype = PGC_INT;
 
-		conf->gen.name_key = guc_name_key(ERROR, conf->gen.name);
+		if (guc_is_name_key(conf->gen.name))
+			conf->gen.name_key = conf->gen.name;
+		else
+			conf->gen.name_key = guc_name_key(ERROR, conf->gen.name);
+
 		num_vars++;
 	}
 
@@ -973,7 +998,11 @@ build_guc_variables(void)
 
 		conf->gen.vartype = PGC_REAL;
 
-		conf->gen.name_key = guc_name_key(ERROR, conf->gen.name);
+		if (guc_is_name_key(conf->gen.name))
+			conf->gen.name_key = conf->gen.name;
+		else
+			conf->gen.name_key = guc_name_key(ERROR, conf->gen.name);
+
 		num_vars++;
 	}
 
@@ -983,7 +1012,11 @@ build_guc_variables(void)
 
 		conf->gen.vartype = PGC_STRING;
 
-		conf->gen.name_key = guc_name_key(ERROR, conf->gen.name);
+		if (guc_is_name_key(conf->gen.name))
+			conf->gen.name_key = conf->gen.name;
+		else
+			conf->gen.name_key = guc_name_key(ERROR, conf->gen.name);
+
 		num_vars++;
 	}
 
@@ -993,7 +1026,11 @@ build_guc_variables(void)
 
 		conf->gen.vartype = PGC_ENUM;
 
-		conf->gen.name_key = guc_name_key(ERROR, conf->gen.name);
+		if (guc_is_name_key(conf->gen.name))
+			conf->gen.name_key = conf->gen.name;
+		else
+			conf->gen.name_key = guc_name_key(ERROR, conf->gen.name);
+
 		num_vars++;
 	}
 
@@ -1212,13 +1249,18 @@ add_placeholder_variable(const char *constname, int elevel)
 		return NULL;
 	}
 
-	name_key = guc_name_key(elevel, name);
-	if (name_key == NULL)
+	if (!guc_is_name_key(name))
 	{
-		guc_free(name);
-		guc_free(var);
-		return NULL;
+		name_key = guc_name_key(elevel, name);
+		if (name_key == NULL)
+		{
+			guc_free(name);
+			guc_free(var);
+			return NULL;
+		}
 	}
+	else
+		name_key = name;
 
 	gen->name = name;
 	gen->context = PGC_USERSET;
@@ -1237,7 +1279,8 @@ add_placeholder_variable(const char *constname, int elevel)
 
 	if (!add_guc_variable((struct config_generic *) var, elevel))
 	{
-		guc_free(name_key);
+		if (name_key != name)
+			guc_free(name_key);
 		guc_free(name);
 		guc_free(var);
 		return NULL;
@@ -4796,7 +4839,10 @@ init_custom_variable(const char *name,
 	memset(gen, 0, sz);
 
 	gen->name = guc_strdup(ERROR, name);
-	gen->name_key = guc_name_key(ERROR, name);
+	if (guc_is_name_key(name))
+		gen->name_key = name;
+	else
+		gen->name_key = guc_name_key(ERROR, name);
 	gen->context = context;
 	gen->group = CUSTOM_OPTIONS;
 	gen->short_desc = short_desc;
diff --git a/src/include/utils/guc_tables.h b/src/include/utils/guc_tables.h
index 41b0316c0b..26bf7e0978 100644
--- a/src/include/utils/guc_tables.h
+++ b/src/include/utils/guc_tables.h
@@ -160,7 +160,8 @@ struct config_generic
 	int			flags;			/* flag bits, see guc.h */
 	/* variable fields, initialized at runtime: */
 	enum config_type vartype;	/* type of variable (set only at startup) */
-	const char *name_key;		/* name folded to lower case */
+	const char *name_key;		/* name folded to lower case; alias of name if
+								 * equal */
 	int			status;			/* status bits, see below */
 	GucSource	source;			/* source of the current actual value */
 	GucSource	reset_source;	/* source of the reset_value */
-- 
2.34.1