From 18bf718f607ad0f11a5e4c5e48916d73c50a16a0 Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Sun, 28 Feb 2021 20:00:27 +0100
Subject: [PATCH] Support wxLANGUAGE_DEFAULT in wxLocale even when it is
 unknown

Don't give an error if we can't recognize the current system language,
as we may still be able to use it even in this case.

Closes #19082.
---
 src/common/intl.cpp | 59 ++++++++++++++++++++++++---------------------
 1 file changed, 32 insertions(+), 27 deletions(-)

diff --git a/src/common/intl.cpp b/src/common/intl.cpp
index 88ee2e0bfe..cb76d6fedf 100644
--- a/src/common/intl.cpp
+++ b/src/common/intl.cpp
@@ -427,43 +427,44 @@ static const char *wxSetlocaleTryUTF8(int c, const wxString& lc)
 }
 #endif // __UNIX__
 
-bool wxLocale::Init(int language, int flags)
+bool wxLocale::Init(int lang, int flags)
 {
 #if WXWIN_COMPATIBILITY_2_8
     wxASSERT_MSG( !(flags & wxLOCALE_CONV_ENCODING),
                   wxS("wxLOCALE_CONV_ENCODING is no longer supported, add charset to your catalogs") );
 #endif
 
-    int lang = language;
-    if (lang == wxLANGUAGE_DEFAULT)
-    {
-        // auto detect the language
-        lang = GetSystemLanguage();
-    }
-
-    // We failed to detect system language, so we will use English:
-    if (lang == wxLANGUAGE_UNKNOWN)
-    {
-        return false;
-    }
+    wxString name, shortName;
 
     const wxLanguageInfo *info = GetLanguageInfo(lang);
 
     // Unknown language:
     if (info == NULL)
     {
-        wxLogError(wxS("Unknown language %i."), lang);
-        return false;
+        // This could have happened because some concrete language has been
+        // requested and we just don't know anything about it. In this case, we
+        // have no choice but to simply give up.
+        if ( lang != wxLANGUAGE_DEFAULT )
+        {
+            wxLogError(wxS("Unknown language %i."), lang);
+            return false;
+        }
+
+        // However in case we didn't recognize the default system language, we
+        // can still try to use it, even though we don't know anything about it
+        // because setlocale() still might.
+    }
+    else
+    {
+        name = info->Description;
+        shortName = info->CanonicalName;
     }
 
-    const wxString& name = info->Description;
-    DoInit(name, info->CanonicalName, lang);
+    DoInit(name, shortName, lang);
 
     // Set the locale:
 #if defined(__UNIX__)
-    const wxString& shortName = info->CanonicalName;
-
-    const char *retloc = wxSetlocaleTryUTF8(LC_ALL, locale);
+    const char *retloc = wxSetlocaleTryUTF8(LC_ALL, shortName);
 
     const wxString langOnly = ExtractLang(shortName);
     if ( !retloc )
@@ -510,11 +511,18 @@ bool wxLocale::Init(int language, int flags)
 #endif // __AIX__
 
 #elif defined(__WIN32__)
-    const char *retloc = "C";
-    if ( info->WinLang == 0 )
+    const char *retloc;
+    if ( !info )
+    {
+        // We're using the system language, but we don't know what it is, so
+        // just use setlocale() to deal with it.
+        retloc = wxSetlocale(LC_ALL, "");
+    }
+    else if ( info->WinLang == 0 )
     {
         wxLogWarning(wxS("Locale '%s' not supported by OS."), name);
-        // retloc already set to "C"
+
+        retloc = "C";
     }
     else // language supported by Windows
     {
@@ -560,14 +568,11 @@ bool wxLocale::Init(int language, int flags)
 #endif
 
 #ifndef WX_NO_LOCALE_SUPPORT
-    // NB: don't use 'lang' here, 'language'
     return DoCommonPostInit
            (
                 retloc != NULL,
                 name,
-                language == wxLANGUAGE_DEFAULT
-                    ? wxString()
-                    : info->CanonicalName,
+                shortName,
                 flags & wxLOCALE_LOAD_DEFAULT
            );
 #endif // !WX_NO_LOCALE_SUPPORT