Avoid crashes in redisplay due to problematic font setups

* src/xdisp.c (handle_single_display_spec)
(produce_stretch_glyph): Avoid crashes if a face's font is NULL.
(Bug#75725)

(cherry picked from commit 77386412050fa348940bf83c5d736ff7b745d5d8)

diff --git a/src/xdisp.c b/src/xdisp.c
index 51b0ecf040515d0c81a6a71cdbddf9905e75c958..f030628124aeaf5a19abdf86dfdebce94498dc55 100644 (file)
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -6194,7 +6194,9 @@ handle_single_display_spec (struct it *it, Lisp_Object spec, Lisp_Object object,
            {
              struct face *face = FACE_FROM_ID (it->f, it->face_id);
              it->voffset = - (XFLOATINT (value)
-                              * (normal_char_height (face->font, -1)));
+                              * (face->font
+                                 ? normal_char_height (face->font, -1)
+                                 : FRAME_LINE_HEIGHT (it->f)));
            }
 #endif /* HAVE_WINDOW_SYSTEM */
        }
@@ -32147,7 +32149,8 @@ produce_stretch_glyph (struct it *it)
   /* Compute height.  */
   if (FRAME_WINDOW_P (it->f))
     {
-      int default_height = normal_char_height (font, ' ');
+      int default_height =
+       font ? normal_char_height (font, ' ') : FRAME_LINE_HEIGHT (it->f);
 
       if ((prop = plist_get (plist, QCheight), !NILP (prop))
          && calc_pixel_width_or_height (&tem, it, prop, font, false, NULL))