[gtk/gtk-3-24: 1/10] Quartz: Don't crash trying to release a NULL CGContext.

[Matthias Clasen <matthiasc src gnome org>]

commit acc1eb917ba800e0067fc1a20f841273769261f6
Author: John Ralls <jralls ceridwen us>
Date:   Sun Jan 30 13:17:43 2022 -0800

    Quartz: Don't crash trying to release a NULL CGContext.

 gdk/quartz/gdkwindow-quartz.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/gdk/quartz/gdkwindow-quartz.c b/gdk/quartz/gdkwindow-quartz.c
index aa85318e0b..5f5f67eb9c 100644
--- a/gdk/quartz/gdkwindow-quartz.c
+++ b/gdk/quartz/gdkwindow-quartz.c
@@ -301,8 +301,9 @@ gdk_quartz_cairo_surface_destroy (void *data)
 
   surface_data->window_impl->cairo_surface = NULL;
 
-  gdk_quartz_window_release_context (surface_data->window_impl,
-                                     surface_data->cg_context);
+  if (surface_data->cg_context)
+       gdk_quartz_window_release_context (surface_data->window_impl,
+                                          surface_data->cg_context);
 
   g_free (surface_data);
 }
@@ -3211,6 +3212,7 @@ gdk_quartz_window_release_context (GdkWindowImplQuartz  *window,
       return;
     }
 
+  g_return_if_fail (cg_context);
   GDK_WINDOW_IMPL_QUARTZ_GET_CLASS (window)->release_context (window, cg_context);
 }