[glib] gobject: Handle ref_count==0 in notify_by_pspec

[Colin Walters <walters src gnome org>]

commit 4b334ef8f1393c997a2d83de4ffe0976dff238c3
Author: Nick Schermer <nick xfce org>
Date:   Wed Aug 7 21:01:00 2013 +0200

    gobject: Handle ref_count==0 in notify_by_pspec
    
    Just like g_object_notify, check for a zero ref_count in
    g_object_notify_by_pspec and leave if it is 0.
    
    This allows using functions in ->finalize() that possibly also
    notify a property change on the object.  Previously,
    this resulted in an error from g_object_ref.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=705570

 gobject/gobject.c          |    3 +++
 gobject/tests/properties.c |    7 +++++++
 2 files changed, 10 insertions(+), 0 deletions(-)
---
diff --git a/gobject/gobject.c b/gobject/gobject.c
index d843d57..96a9d4f 100644
--- a/gobject/gobject.c
+++ b/gobject/gobject.c
@@ -1238,6 +1238,9 @@ g_object_notify_by_pspec (GObject    *object,
   g_return_if_fail (G_IS_OBJECT (object));
   g_return_if_fail (G_IS_PARAM_SPEC (pspec));
 
+  if (g_atomic_int_get (&object->ref_count) == 0)
+    return;
+
   g_object_ref (object);
   g_object_notify_by_spec_internal (object, pspec);
   g_object_unref (object);
diff --git a/gobject/tests/properties.c b/gobject/tests/properties.c
index 27c2a22..7140f90 100644
--- a/gobject/tests/properties.c
+++ b/gobject/tests/properties.c
@@ -67,6 +67,13 @@ test_object_finalize (GObject *gobject)
 {
   g_free (((TestObject *) gobject)->baz);
 
+  /* When the ref_count of an object is zero it is still
+   * possible to notify the property, but it should do
+   * nothing and silenty quit (bug #705570)
+   */
+  g_object_notify (gobject, "foo");
+  g_object_notify_by_pspec (gobject, properties[PROP_BAR]);
+
   G_OBJECT_CLASS (test_object_parent_class)->finalize (gobject);
 }