[gegl] gegl_node_add_child: g_return_if_fail() if the child already has a parent

[Michael Natterer <mitch src gnome org>]

commit 1aec759c9622cf4292cf47bca1d162b0c48277e7
Author: Michael Natterer <mitch gimp org>
Date:   Fri Sep 23 21:48:11 2011 +0200

    gegl_node_add_child: g_return_if_fail() if the child already has a parent

 gegl/graph/gegl-node.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/gegl/graph/gegl-node.c b/gegl/graph/gegl-node.c
index b4bc98e..01bc2b2 100644
--- a/gegl/graph/gegl-node.c
+++ b/gegl/graph/gegl-node.c
@@ -2058,6 +2058,7 @@ gegl_node_add_child (GeglNode *self,
 {
   g_return_val_if_fail (GEGL_IS_NODE (self), NULL);
   g_return_val_if_fail (GEGL_IS_NODE (child), NULL);
+  g_return_val_if_fail (child->priv->parent == NULL, NULL);
 
   self->priv->children = g_slist_prepend (self->priv->children,
                                           g_object_ref (child));