[mutter] workspace: Downgrade assert to warning when adding window

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

commit b55b26661f748791fd7207bf5c43b332e8da094c
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu Jan 28 18:59:22 2021 +0100

    workspace: Downgrade assert to warning when adding window
    
    An extension can by accident cause us to end up in a state where we try
    to add the same window to a workspace twice. When this happens we
    shouldn't crash, but instead complain loudly.
    
    Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/992
    Related: https://gitlab.gnome.org/GNOME/gnome-shell-extensions/-/merge_requests/157
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1692>

 src/core/workspace.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/src/core/workspace.c b/src/core/workspace.c
index 62328ad31a..002ee8e566 100644
--- a/src/core/workspace.c
+++ b/src/core/workspace.c
@@ -369,10 +369,11 @@ void
 meta_workspace_add_window (MetaWorkspace *workspace,
                            MetaWindow    *window)
 {
+  g_return_if_fail (g_list_find (workspace->mru_list, window) == NULL);
+
   COGL_TRACE_BEGIN_SCOPED (MetaWorkspaceAddWindow,
                            "Workspace (add window)");
 
-  g_assert (g_list_find (workspace->mru_list, window) == NULL);
   workspace->mru_list = g_list_prepend (workspace->mru_list, window);
 
   workspace->windows = g_list_prepend (workspace->windows, window);