[gtk/gtk-3-24] x11: Be a lot more careful about setting ParentRelative

[Benjamin Otte <otte src gnome org>]

commit 6a47e9a8b901b05b7a3ffb6e3929e339bbe7abc0
Author: Benjamin Otte <otte redhat com>
Date:   Thu Dec 13 05:22:18 2018 +0100

    x11: Be a lot more careful about setting ParentRelative
    
    We don't want to set ParentRelative when:
    
    - the parent window is NULL
      In that case we are unsure about the depth, so better err on the side
      of caution and avoid a BadMatch by accepting ugly output.
    - the cairo pattern is in an error status
      This should never happen - unless you start up in OOM - but better
      be safe than sorry.
    
    Might help with the spurious crashes in #1280.

 gdk/x11/gdkwindow-x11.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/gdk/x11/gdkwindow-x11.c b/gdk/x11/gdkwindow-x11.c
index f1f2081b6b..97ada6d739 100644
--- a/gdk/x11/gdkwindow-x11.c
+++ b/gdk/x11/gdkwindow-x11.c
@@ -3005,7 +3005,8 @@ G_GNUC_END_IGNORE_DEPRECATIONS
       /* X throws BadMatch if the parent has a different depth when
        * using ParentRelative */
       parent = gdk_window_get_parent (window);
-      if (parent == NULL || window->depth == parent->depth)
+      if (parent != NULL && window->depth == parent->depth &&
+          cairo_pattern_status (pattern) == CAIRO_STATUS_SUCCESS)
         {
           XSetWindowBackgroundPixmap (GDK_WINDOW_XDISPLAY (window),
                                       GDK_WINDOW_XID (window), ParentRelative);