[glib: 1/2] gapplication: Add postconditions on calls to GApplication.dbus_register

[Sebastian Dröge <sdroege src gnome org>]

commit 539621d2d3d058d20e11aedc09efc6bd0acdbe69
Author: Philip Withnall <withnall endlessm com>
Date:   Fri Nov 17 11:02:35 2017 +0000

    gapplication: Add postconditions on calls to GApplication.dbus_register
    
    Try and catch programmer errors in third-party implementations of
    `dbus_register()`.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>
    
    Fixes: #1188

 gio/gapplicationimpl-dbus.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)
---
diff --git a/gio/gapplicationimpl-dbus.c b/gio/gapplicationimpl-dbus.c
index 6f02788a2..263001b8e 100644
--- a/gio/gapplicationimpl-dbus.c
+++ b/gio/gapplicationimpl-dbus.c
@@ -371,6 +371,7 @@ g_application_impl_attempt_primary (GApplicationImpl  *impl,
   GApplicationFlags app_flags;
   GVariant *reply;
   guint32 rval;
+  GError *local_error = NULL;
 
   if (org_gtk_Application == NULL)
     {
@@ -430,8 +431,14 @@ g_application_impl_attempt_primary (GApplicationImpl  *impl,
   if (!app_class->dbus_register (impl->app,
                                  impl->session_bus,
                                  impl->object_path,
-                                 error))
-    return FALSE;
+                                 &local_error))
+    {
+      g_return_val_if_fail (local_error != NULL, FALSE);
+      g_propagate_error (error, g_steal_pointer (&local_error));
+      return FALSE;
+    }
+
+  g_return_val_if_fail (local_error == NULL, FALSE);
 
   if (impl->bus_name == NULL)
     {