From 51ad2a55a8aa1e6278e76f8636653b0d9db784b4 Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Sun, 14 May 2023 07:46:44 -0400
Subject: [PATCH] gdk: Add an assertion

We simply overwrite any previous region,
so assert that the field was NULL before.
---
 gdk/gdktexture.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gdk/gdktexture.c b/gdk/gdktexture.c
index b392b90222..8c8de2d42d 100644
--- a/gdk/gdktexture.c
+++ b/gdk/gdktexture.c
@@ -711,6 +711,8 @@ gdk_texture_set_diff (GdkTexture     *self,
                       GdkTexture     *previous,
                       cairo_region_t *diff)
 {
+  g_assert (self->diff_to_previous == NULL);
+
   self->previous_texture = previous;
   self->diff_to_previous = diff;
   g_atomic_pointer_set (&previous->next_texture, self);
-- 
2.30.2