Ticket #15963: 15963.3.diff

wp-includes/post.php

@@ -3442 +3442 @@
         $uri = $page->post_name;
 
         foreach ( $page->ancestors as $parent ) {
-                $uri = get_post( $parent )->post_name . "/" . $uri;
+                if ( $parent = get_post( $parent ) )
+                        $uri = $parent->post_name . '/' . $uri;
         }
 
         return $uri;