[mutter] plugins/default: Use local vars for refs

[Marge Bot <marge-bot src gnome org>]

commit 7bb0055acd436ede3ec701d477ef9494bdf267a3
Author: Erik Massop <emassop google com>
Date:   Sun Nov 28 00:14:28 2021 +0000

    plugins/default: Use local vars for refs
    
    Since the completion callback (on_switch_workspace_effect_complete) sets
    priv->tml_switch_workspace1 to NULL, the unref was trying to unref NULL,
    and the reffed ClutterTimeline was not getting unreffed.
    
    This could be triggered by rapidly switching workspaces, switching again
    before the animation of the initial switch was done.
    
    Found while working on #2038.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2120>

 src/compositor/plugins/default.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)
---
diff --git a/src/compositor/plugins/default.c b/src/compositor/plugins/default.c
index e3fbfb40cb..f762b3e6e2 100644
--- a/src/compositor/plugins/default.c
+++ b/src/compositor/plugins/default.c
@@ -897,17 +897,20 @@ finish_timeline (ClutterTimeline *timeline)
 }
 
 static void
-kill_switch_workspace (MetaPlugin     *plugin)
+kill_switch_workspace (MetaPlugin *plugin)
 {
   MetaDefaultPluginPrivate *priv = META_DEFAULT_PLUGIN (plugin)->priv;
 
   if (priv->tml_switch_workspace1)
     {
-      g_object_ref (priv->tml_switch_workspace1);
-      clutter_timeline_stop (priv->tml_switch_workspace1);
-      clutter_timeline_stop (priv->tml_switch_workspace2);
-      g_signal_emit_by_name (priv->tml_switch_workspace1, "completed", NULL);
-      g_object_unref (priv->tml_switch_workspace1);
+      g_autoptr (ClutterTimeline) timeline1 = NULL;
+      g_autoptr (ClutterTimeline) timeline2 = NULL;
+
+      timeline1 = g_object_ref (priv->tml_switch_workspace1);
+      timeline2 = g_object_ref (priv->tml_switch_workspace2);
+
+      finish_timeline (timeline1);
+      finish_timeline (timeline2);
     }
 }