Avoid segfaults in lookup_image when faces were freed

* src/image.c (lookup_image): Make sure the frame's face cache
exists and has at least the basic faces.  If FACE_ID is not a
basic face, and is no longer cached, fall back on the 'default'
face.  (Bug#43700)

diff --git a/src/image.c b/src/image.c
index 6ecf6a70fe262eaaee88e8c6ef97fb2fc0a5f67c..25d5af8a8d55f3a8dcdd73549daf1ad1e96ced20 100644 (file)
--- a/src/image.c
+++ b/src/image.c
@@ -2329,8 +2329,14 @@ lookup_image (struct frame *f, Lisp_Object spec, int face_id)
   struct image *img;
   EMACS_UINT hash;
 
-  struct face *face = (face_id >= 0) ? FACE_FROM_ID (f, face_id)
-    : FACE_FROM_ID (f, DEFAULT_FACE_ID);
+  if (FRAME_FACE_CACHE (f) == NULL)
+    init_frame_faces (f);
+  if (FRAME_FACE_CACHE (f)->used == 0)
+    recompute_basic_faces (f);
+  if (face_id < 0 || face_id >= FRAME_FACE_CACHE (f)->used)
+    face_id = DEFAULT_FACE_ID;
+
+  struct face *face = FACE_FROM_ID (f, face_id);
   unsigned long foreground = FACE_COLOR_TO_PIXEL (face->foreground, f);
   unsigned long background = FACE_COLOR_TO_PIXEL (face->background, f);