[gnome-initial-setup/mcatanzaro/uselocale-error-checking] Check for errors from newlocale()

[Michael Catanzaro <mcatanzaro src gnome org>]

commit a690f778d77746f8f7dab4d37c10d07d2849424a
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Tue Jun 4 16:12:29 2019 -0500

    Check for errors from newlocale()
    
    We accidentally deleted all locales from Fedora in yesterday's rawhide
    build. This revealed a bug in my uselocale changes to
    gnome-initial-setup: when a locale is missing from the system, g-i-s
    will crash rather than degrading gracefully. This is easy to fix, so
    let's do so.
    
    We also ignore errors from uselocale(), but this is probably OK because
    the only possible error is passing in an invalid locale object, which is
    no longer possible after this commit.
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1716691

 gnome-initial-setup/gis-driver.c                        | 9 ++++++++-
 gnome-initial-setup/pages/language/gis-welcome-widget.c | 7 +++++++
 2 files changed, 15 insertions(+), 1 deletion(-)
---
diff --git a/gnome-initial-setup/gis-driver.c b/gnome-initial-setup/gis-driver.c
index c1ccee2..a377f55 100644
--- a/gnome-initial-setup/gis-driver.c
+++ b/gnome-initial-setup/gis-driver.c
@@ -23,8 +23,9 @@
 
 #include "gnome-initial-setup.h"
 
-#include <stdlib.h>
+#include <errno.h>
 #include <locale.h>
+#include <stdlib.h>
 #include <gdm/gdm-client.h>
 
 #include "cc-common-language.h"
@@ -199,6 +200,12 @@ gis_driver_set_user_language (GisDriver *driver, const gchar *lang_id, gboolean
   if (update_locale)
     {
       locale_t locale = newlocale (LC_MESSAGES_MASK, lang_id, (locale_t) 0);
+      if (locale == (locale_t) 0)
+        {
+          g_warning ("Failed to create locale %s: %s", lang_id, g_strerror (errno));
+          return;
+        }
+
       uselocale (locale);
 
       if (priv->locale != (locale_t) 0 && priv->locale != LC_GLOBAL_LOCALE)
diff --git a/gnome-initial-setup/pages/language/gis-welcome-widget.c 
b/gnome-initial-setup/pages/language/gis-welcome-widget.c
index 37b000f..7777638 100644
--- a/gnome-initial-setup/pages/language/gis-welcome-widget.c
+++ b/gnome-initial-setup/pages/language/gis-welcome-widget.c
@@ -22,6 +22,7 @@
 #include "config.h"
 #include "gis-welcome-widget.h"
 
+#include <errno.h>
 #include <locale.h>
 #include <glib/gi18n.h>
 
@@ -116,6 +117,12 @@ welcome (const char *locale_id)
   char *welcome;
 
   locale = newlocale (LC_MESSAGES_MASK, locale_id, (locale_t) 0);
+  if (locale == (locale_t) 0)
+    {
+      g_warning ("Failed to create locale %s: %s", locale_id, g_strerror (errno));
+      return "Welcome!";
+    }
+
   old_locale = uselocale (locale);
 
   /* Translators: This is meant to be a warm, engaging welcome message,