window/wayland: Always update monitor for non-user ops

meta_window_wayland_update_main_monitor() would skip the monitor update
if the difference in scale between the old and the new monitor would
cause another monitor change.

While this is suitable when the monitor change results from a user
interactively moving the surface between monitors of different scales,
this can leave dangling pointers to freed monitors when this is
triggered by a change of monitor configuration.

Make sure we update the monitor unconditionally if not from a user
operation.

Closes: https://gitlab.gnome.org/GNOME/mutter/issues/189
(cherry picked from commit a3da4b8d5bd217c0262fd9361036877d155a300f)

Bug-GNOME: https://gitlab.gnome.org/GNOME/mutter/issues/189
Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1784398
Applied-Upstream: 3.28.4, commit:https://gitlab.gnome.org/GNOME/mutter/commit/d74a04606

Gbp-Pq: Name window-wayland-Always-update-monitor-for-non-user-ops.patch

diff --git a/src/wayland/meta-window-wayland.c b/src/wayland/meta-window-wayland.c
index 705bc498105582000b09883cb078068e17c5bed6..8bafb252f4f435724aba162c2be40e8e4f16b6c6 100644 (file)
--- a/src/wayland/meta-window-wayland.c
+++ b/src/wayland/meta-window-wayland.c
@@ -413,6 +413,12 @@ meta_window_wayland_update_main_monitor (MetaWindow *window,
       return;
     }
 
+  if (!user_op)
+    {
+      window->monitor = to;
+      return;
+    }
+
   from_scale = meta_logical_monitor_get_scale (from);
   to_scale = meta_logical_monitor_get_scale (to);