[mutter] window: Emit an error and return when trying to activate an unmanaged

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit a6fc656e917fd48b8708b8d9f4bf9f8b15581313
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Fri May 3 13:10:47 2019 -0500

    window: Emit an error and return when trying to activate an unmanaged
    
    If something (i.e. gnome-shell or an extension) tries to activate an unmanaged
    window, we should warn about this and avoid to perform further actions as this
    could lead to a crash of mutter, since the window has not valid flags (like
    workspace) set anymore at this stage.
    
    Fixes https://gitlab.gnome.org/GNOME/mutter/issues/580
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/564

 src/core/window.c | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/src/core/window.c b/src/core/window.c
index caa1059e3..d8384c3a8 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -3679,6 +3679,13 @@ meta_window_activate_full (MetaWindow     *window,
 {
   MetaWorkspaceManager *workspace_manager = window->display->workspace_manager;
   gboolean allow_workspace_switch;
+
+  if (window->unmanaging)
+    {
+      g_warning ("Trying to activate unmanaged window '%s'", window->desc);
+      return;
+    }
+
   meta_topic (META_DEBUG_FOCUS,
               "_NET_ACTIVE_WINDOW message sent for %s at time %u "
               "by client type %u.\n",