window-props: don't set override-redirect window as parentgnome-3-36

Before commit c656c658940d override-redirect windows was not
registered with meta_display_register_x_window. This means
that Metacity was treating WM_TRANSIENT_FOR hint as invalid
if it was pointing to override-redirect window.

EWMH specification [1] says that WM_TRANSIENT_FOR property is
defined for managed windows and extends its usage for
override-redirect windows. Client should set WM_TRANSIENT_FOR
on override-redirect window if it is child/popup for another
window.

As specification does not say anyting about using
override-redirect windows as parent for managed windows and
because it causes crashes in Metacity ignore WM_TRANSIENT_FOR
if it is pointing to override-redirect window.

[1] https://specifications.freedesktop.org/wm-spec/wm-spec-latest.html#idm46291029654544

https://gitlab.gnome.org/GNOME/metacity/-/issues/18

1 files changed, 10 insertions, 0 deletions

diff --git a/src/core/window-props.c b/src/core/window-props.c
index 64d500bd..2858c291 100644
--- a/src/core/window-props.c
+++ b/src/core/window-props.c
@@ -1623,6 +1623,16 @@ reload_transient_for (MetaWindow    *window,
                      transient_for, window->desc);
           transient_for = None;
         }
+      else if (parent->override_redirect)
+        {
+          g_warning ("Ignoring WM_TRANSIENT_FOR for %s because it is pointing "
+                     "to override-redirect window %s.",
+                     window->desc,
+                     parent->desc);
+
+          transient_for = None;
+          parent = NULL;
+        }
 
       /* Make sure there is not a loop */
       while (parent)