[gtk+] Fix a segfault in gtk_statusbar_remove_all

[Matthias Clasen <matthiasc src gnome org>]

commit 30958ea8ad1a60449eb6ad47eb679a2de70d96ed
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Jan 31 11:32:19 2011 -0500

    Fix a segfault in gtk_statusbar_remove_all
    
    https://bugzilla.gnome.org/show_bug.cgi?id=640487

 gtk/gtkstatusbar.c  |    5 ++++-
 gtk/tests/testing.c |   21 +++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkstatusbar.c b/gtk/gtkstatusbar.c
index 6483f32..f3518c5 100644
--- a/gtk/gtkstatusbar.c
+++ b/gtk/gtkstatusbar.c
@@ -529,7 +529,10 @@ gtk_statusbar_remove_all (GtkStatusbar *statusbar,
           if (prev == NULL)
             prev = priv->messages;
 
-          list = prev->next;
+          if (prev)
+            list = prev->next;
+          else
+            list = NULL;
         }
       else
         {
diff --git a/gtk/tests/testing.c b/gtk/tests/testing.c
index bc002f6..07cd8d4 100644
--- a/gtk/tests/testing.c
+++ b/gtk/tests/testing.c
@@ -232,17 +232,38 @@ test_spin_button_arrows (void)
   g_assert (oldval == 0);
 }
 
+static void
+test_statusbar_remove_all (void)
+{
+  GtkWidget *statusbar;
+
+  g_test_bug ("640487");
+
+  statusbar = gtk_statusbar_new ();
+  g_object_ref_sink (statusbar);
+
+  gtk_statusbar_push (GTK_STATUSBAR (statusbar), 1, "bla");
+  gtk_statusbar_push (GTK_STATUSBAR (statusbar), 1, "bla");
+  gtk_statusbar_remove_all (GTK_STATUSBAR (statusbar), 1);
+
+  g_object_unref (statusbar);
+}
+
 int
 main (int   argc,
       char *argv[])
 {
   gtk_test_init (&argc, &argv);
+  g_test_bug_base ("http://bugzilla.gnome.org/";);
   gtk_test_register_all_types();
+
+  g_test_add_func ("/tests/statusbar-remove-all", test_statusbar_remove_all);
   g_test_add_func ("/ui-tests/text-access", test_text_access);
   g_test_add_func ("/ui-tests/button-clicks", test_button_clicks);
   g_test_add_func ("/ui-tests/keys-events", test_button_keys);
   g_test_add_func ("/ui-tests/slider-ranges", test_slider_ranges);
   g_test_add_func ("/ui-tests/xserver-sync", test_xserver_sync);
   g_test_add_func ("/ui-tests/spin-button-arrows", test_spin_button_arrows);
+
   return g_test_run();
 }