From 6c7ccbd9e77fd377c8eae97323fbdadd77d3192f Mon Sep 17 00:00:00 2001
From: John Ralls <jralls@ceridwen.us>
Date: Sun, 28 Apr 2019 16:34:58 -0700
Subject: [PATCH] Bug 797134 - Decimal separator: Windows configured as dot,...

Gnucash shows comma.

This was introduced by 8f88b7f2b. It turns out that Windows
implementation of setlocale works only if the POSIX locale environment
variables (i.e. LC_FOO or LANG) are set, otherwise it returns NULL. We
were unknowingly relying on Guile to retrieve the Windows environment
for us and that would do the wrong thing if the user had set the locale
in the environment file, so 8f88b7f2b restored it... unfortunately to
the C locale.

This commit changes the set_win32_thread_locale function to work in
both directions, setting both locales from the environment variables
if any are set and calling setlocale with the result of
GetUserDefaultLocaleName if not.
---
 gnucash/gnucash-bin.c | 60 ++++++++++++++++++++++++++++---------------
 1 file changed, 39 insertions(+), 21 deletions(-)

diff --git a/gnucash/gnucash-bin.c b/gnucash/gnucash-bin.c
index 12866092f5..3278d3ae61 100644
--- a/gnucash/gnucash-bin.c
+++ b/gnucash/gnucash-bin.c
@@ -763,31 +763,49 @@ gnc_log_init()
 }
 
 #ifdef __MINGW32__
-/* Set the Win32 internal localization for the main thread if the
- * locale has been overridden in the environment. Note that this is
- * separate from what setlocale() does; that only affects POSIX
- * functions and does *not* set the Windows locale.
+/* If one of the Unix locale variables LC_ALL, LC_MESSAGES, or LANG is
+ * set in the environment check to see if it's a valid locale and if
+ * it is set both the Windows and POSIX locales to that. If not
+ * retrieve the Windows locale and set POSIX to match.
  */
 static void
 set_win32_thread_locale()
 {
-    gunichar2* wlocale = NULL;
+    WCHAR lpLocaleName[LOCALE_NAME_MAX_LENGTH];
     char *locale = NULL;
-    int len = 0;
-    if (((locale = getenv ("LC_ALL")) == NULL || locale[0] == '\0')
-      && ((locale = getenv ("LC_MESSAGES")) == NULL || locale[0] == '\0')
-      && ((locale = getenv ("LANG")) == NULL || locale[0] == '\0'))
-	return;
-    len = strchr(locale, '.') - locale;
-    locale[2] = '-';
-    wlocale = g_utf8_to_utf16 (locale, len, NULL, NULL, NULL);
-    if (IsValidLocaleName(wlocale))
+
+    if (((locale = getenv ("LC_ALL")) != NULL && locale[0] != '\0') ||
+      ((locale = getenv ("LC_MESSAGES")) != NULL && locale[0] != '\0') ||
+      ((locale = getenv ("LANG")) != NULL && locale[0] != '\0'))
     {
-	LCID lcid = LocaleNameToLCID(wlocale, LOCALE_ALLOW_NEUTRAL_NAMES);
-	SetThreadLocale(lcid);
+	gunichar2* wlocale = NULL;
+	int len = 0;
+	len = strchr(locale, '.') - locale;
+	locale[2] = '-';
+	wlocale = g_utf8_to_utf16 (locale, len, NULL, NULL, NULL);
+	if (IsValidLocaleName(wlocale))
+	{
+	    LCID lcid = LocaleNameToLCID(wlocale, LOCALE_ALLOW_NEUTRAL_NAMES);
+	    printf ("win32_thread_locale setting %s from unix environment.\n",
+		    locale);
+	    SetThreadLocale(lcid);
+	    setlocale (LC_ALL, locale);
+	    sys_locale = locale;
+	    g_free(locale);
+	    g_free(wlocale);
+	    return;
+	}
+	g_free(locale);
+	g_free(wlocale);
+    }
+    if (GetUserDefaultLocaleName(lpLocaleName, LOCALE_NAME_MAX_LENGTH))
+    {
+	sys_locale = g_utf16_to_utf8((gunichar2*)lpLocaleName,
+				     LOCALE_NAME_MAX_LENGTH,
+				     NULL, NULL, NULL);
+	setlocale (LC_ALL, sys_locale);
+	return;
     }
-    g_free(locale);
-    g_free(wlocale);
 }
 #endif
 
@@ -814,12 +832,12 @@ main(int argc, char ** argv)
      */
 #ifdef MAC_INTEGRATION
     set_mac_locale();
+#elif defined __MINGW32__
+    set_win32_thread_locale();
 #endif
     gnc_environment_setup();
-#ifndef MAC_INTEGRATION /* setlocale already done */
+#if ! defined MAC_INTEGRATION && ! defined __MINGW32__/* setlocale already done */
     sys_locale = g_strdup (setlocale (LC_ALL, ""));
-#ifdef __MINGW32__
-    set_win32_thread_locale();
 #endif
     if (!sys_locale)
       {