[gegl] buffer: in gegl_buffer_copy(), explicitly damage COW-ed rect

[Ell <ell src gnome org>]

commit f9df6a848aadeee31097047605b510c9bad3d5ee
Author: Ell <ell_se yahoo com>
Date:   Wed Nov 28 09:03:25 2018 -0500

    buffer: in gegl_buffer_copy(), explicitly damage COW-ed rect
    
    ... in preparation for removing the implicit tile voiding during
    gegl_tile_handler_cache_insert() in the next commit.

 gegl/buffer/gegl-buffer-access.c | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/gegl/buffer/gegl-buffer-access.c b/gegl/buffer/gegl-buffer-access.c
index 8814c81d5..8a8b7865e 100644
--- a/gegl/buffer/gegl-buffer-access.c
+++ b/gegl/buffer/gegl-buffer-access.c
@@ -2503,6 +2503,14 @@ gegl_buffer_copy (GeglBuffer          *src,
               }
 
             g_rec_mutex_unlock (&src->tile_storage->mutex);
+
+            gegl_tile_handler_damage_rect (
+              GEGL_TILE_HANDLER (dst->tile_storage),
+              GEGL_RECTANGLE (cow_rect.x + dst->shift_x,
+                              cow_rect.y + dst->shift_y,
+                              cow_rect.width,
+                              cow_rect.height));
+
             g_rec_mutex_unlock (&dst->tile_storage->mutex);
           }