v4-0008-No-longer-accept-NULL-for-wchar2char-char2wchar.patch

From 70b7e1012daec72641d866bf09385933a98d1d42 Mon Sep 17 00:00:00 2001
From: Jeff Davis <jeff@j-davis.com>
Date: Mon, 7 Jul 2025 15:43:48 -0700
Subject: [PATCH v4 8/8] No longer accept NULL for wchar2char()/char2wchar().

Avoid dependence on setlocale().

Discussion: https://postgr.es/m/9875f7f9-50f1-4b5d-86fc-ee8b03e8c162@eisentraut.org
---
 src/backend/utils/adt/pg_locale.c      |  2 +-
 src/backend/utils/adt/pg_locale_libc.c | 24 +++++-------------------
 2 files changed, 6 insertions(+), 20 deletions(-)

diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 97c2ac1faf9..ce50e9e15d0 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -998,7 +998,7 @@ get_iso_localename(const char *winlocname)
 		char	   *hyphen;
 
 		/* Locale names use only ASCII, any conversion locale suffices. */
-		rc = wchar2char(iso_lc_messages, buffer, sizeof(iso_lc_messages), NULL);
+		rc = wchar2char(iso_lc_messages, buffer, sizeof(iso_lc_messages), LC_C_LOCALE);
 		if (rc == -1 || rc == sizeof(iso_lc_messages))
 			return NULL;
 
diff --git a/src/backend/utils/adt/pg_locale_libc.c b/src/backend/utils/adt/pg_locale_libc.c
index 33a082b6490..4013771e301 100644
--- a/src/backend/utils/adt/pg_locale_libc.c
+++ b/src/backend/utils/adt/pg_locale_libc.c
@@ -1169,6 +1169,8 @@ wchar2char(char *to, const wchar_t *from, size_t tolen, locale_t loc)
 {
 	size_t		result;
 
+	Assert(loc != NULL);
+
 	if (tolen == 0)
 		return 0;
 
@@ -1195,16 +1197,7 @@ wchar2char(char *to, const wchar_t *from, size_t tolen, locale_t loc)
 	}
 	else
 #endif							/* WIN32 */
-	if (loc == (locale_t) 0)
-	{
-		/* Use wcstombs directly for the default locale */
-		result = wcstombs(to, from, tolen);
-	}
-	else
-	{
-		/* Use wcstombs_l for nondefault locales */
 		result = wcstombs_l(to, from, tolen, loc);
-	}
 
 	return result;
 }
@@ -1224,6 +1217,8 @@ char2wchar(wchar_t *to, size_t tolen, const char *from, size_t fromlen,
 {
 	size_t		result;
 
+	Assert(loc != NULL);
+
 	if (tolen == 0)
 		return 0;
 
@@ -1255,16 +1250,7 @@ char2wchar(wchar_t *to, size_t tolen, const char *from, size_t fromlen,
 		/* mbstowcs requires ending '\0' */
 		char	   *str = pnstrdup(from, fromlen);
 
-		if (loc == (locale_t) 0)
-		{
-			/* Use mbstowcs directly for the default locale */
-			result = mbstowcs(to, str, tolen);
-		}
-		else
-		{
-			/* Use mbstowcs_l for nondefault locales */
-			result = mbstowcs_l(to, str, tolen, loc);
-		}
+		result = mbstowcs_l(to, str, tolen, loc);
 
 		pfree(str);
 	}
-- 
2.43.0