[gtk/matthiasc/for-master-2: 8/16] notebook: Don't trigger criticals in dispose

[Matthias Clasen <matthiasc src gnome org>]

commit b1d5de78e1f73f26f741d6c6043a644889c3008f
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Feb 4 22:42:44 2020 +0100

    notebook: Don't trigger criticals in dispose
    
    When we dismantle our children in dispose, we
    trigger a11y children-changed signals which end
    up calling back into the notebook. Handle this
    without critical warnings.

 gtk/gtknotebook.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/gtk/gtknotebook.c b/gtk/gtknotebook.c
index 73486d71fb..b3feea7fe3 100644
--- a/gtk/gtknotebook.c
+++ b/gtk/gtknotebook.c
@@ -6544,7 +6544,8 @@ gtk_notebook_get_tab_label (GtkNotebook *notebook,
   g_return_val_if_fail (GTK_IS_WIDGET (child), NULL);
 
   list = gtk_notebook_find_child (notebook, child);
-  g_return_val_if_fail (list != NULL, NULL);
+  if (list == NULL)
+    return NULL;
 
   if (GTK_NOTEBOOK_PAGE_FROM_LIST (list)->default_tab)
     return NULL;