[mutter/wip/carlosg/shutdown-warning] compositor: Detach window and actor both ways on actor dispose

[Carlos Garnacho <carlosg src gnome org>]

commit ebc70272fce24ea7e31620b38ab5b06d142dc311
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Apr 30 14:59:43 2022 +0200

    compositor: Detach window and actor both ways on actor dispose
    
    This is currently deferred to the window being unmanaged, however
    the dependency of events is too indirect to consider these things
    always happen one after the other.
    
    Fixes possible warnings like:
    
    (mutter:872101): GLib-GObject-WARNING **: 15:29:27.943: invalid unclassed pointer in cast to 
'MetaWindowActor'
    
    Seen on shutdown, a reliable reproducer is gnome-settings-daemon
    test suite.

 src/compositor/meta-window-actor.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/src/compositor/meta-window-actor.c b/src/compositor/meta-window-actor.c
index 9cee56a371..59ae4163c6 100644
--- a/src/compositor/meta-window-actor.c
+++ b/src/compositor/meta-window-actor.c
@@ -447,7 +447,11 @@ meta_window_actor_dispose (GObject *object)
 
   meta_compositor_remove_window_actor (compositor, self);
 
-  g_clear_object (&priv->window);
+  if (priv->window)
+    {
+      meta_window_set_compositor_private (priv->window, NULL);
+      g_clear_object (&priv->window);
+    }
 
   if (priv->surface)
     {