[glib] GApplication: Assert that dbus_unregister was called before destruction

[Debarshi Ray <debarshir src gnome org>]

commit c1ae1170fa47483b9bcb30de8cd346cbc4fe10e3
Author: Debarshi Ray <debarshir gnome org>
Date:   Mon Jun 19 16:16:08 2017 +0200

    GApplication: Assert that dbus_unregister was called before destruction
    
    Invoking the dbus_unregister virtual method during destruction is
    problematic. It would happen after a sub-class has dropped its
    references to its instance objects, and it is surprising to be asked to
    unexport exported D-Bus objects after that.
    
    This problem was masked as a side-effect of commit 21b1c390a3ce1f7e.
    Let's ensure that it doesn't regress by asserting that dbus_unregister
    has happened before destruction.
    
    Based on a patch by Giovanni Campagna.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=725950

 gio/gapplication.c |   17 ++++++++++++++---
 1 files changed, 14 insertions(+), 3 deletions(-)
---
diff --git a/gio/gapplication.c b/gio/gapplication.c
index c00973d..991e5d8 100644
--- a/gio/gapplication.c
+++ b/gio/gapplication.c
@@ -1243,10 +1243,23 @@ g_application_constructed (GObject *object)
 }
 
 static void
+g_application_dispose (GObject *object)
+{
+  GApplication *application = G_APPLICATION (object);
+
+  g_assert_null (application->priv->impl);
+
+  G_OBJECT_CLASS (g_application_parent_class)
+    ->dispose (object);
+}
+
+static void
 g_application_finalize (GObject *object)
 {
   GApplication *application = G_APPLICATION (object);
 
+  g_assert_null (application->priv->impl);
+
   g_slist_free_full (application->priv->option_groups, (GDestroyNotify) g_option_group_unref);
   if (application->priv->main_options)
     g_option_group_unref (application->priv->main_options);
@@ -1254,9 +1267,6 @@ g_application_finalize (GObject *object)
     g_hash_table_unref (application->priv->packed_options);
 
   g_slist_free_full (application->priv->option_strings, g_free);
-
-  if (application->priv->impl)
-    g_application_impl_destroy (application->priv->impl);
   g_free (application->priv->id);
 
   if (g_application_get_default () == application)
@@ -1314,6 +1324,7 @@ g_application_class_init (GApplicationClass *class)
   GObjectClass *object_class = G_OBJECT_CLASS (class);
 
   object_class->constructed = g_application_constructed;
+  object_class->dispose = g_application_dispose;
   object_class->finalize = g_application_finalize;
   object_class->get_property = g_application_get_property;
   object_class->set_property = g_application_set_property;