[gnome-photos] pipeline: Silence a WARNING by working around a GEGL bug

[Debarshi Ray <debarshir src gnome org>]

commit ef8a6f2fe9a32382ee9c71e9182385cd7e34ed8e
Author: Debarshi Ray <debarshir gnome org>
Date:   Tue Dec 29 22:29:02 2015 +0100

    pipeline: Silence a WARNING by working around a GEGL bug

 src/photos-pipeline.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)
---
diff --git a/src/photos-pipeline.c b/src/photos-pipeline.c
index 6c04bf4..b1f9688 100644
--- a/src/photos-pipeline.c
+++ b/src/photos-pipeline.c
@@ -134,9 +134,17 @@ photos_pipeline_dispose (GObject *object)
 {
   PhotosPipeline *self = PHOTOS_PIPELINE (object);
 
+  /* We must drop all references to the child nodes before destroying
+   * the graph. The other option would be to ensure that the
+   * GeglProcessor is destroyed before its Pipeline, but since that is
+   * harder to enforce, let's do this instead.
+   *
+   * See: https://bugzilla.gnome.org/show_bug.cgi?id=759995
+   */
+  g_clear_pointer (&self->hash, (GDestroyNotify) g_hash_table_unref);
+
   g_clear_object (&self->graph);
   g_clear_object (&self->parent);
-  g_clear_pointer (&self->hash, (GDestroyNotify) g_hash_table_unref);
 
   G_OBJECT_CLASS (photos_pipeline_parent_class)->dispose (object);
 }