1 files changed, 4 insertions, 0 deletions

diff --git a/src/font.c b/src/font.c
index 935dd64e648..6bc977fd68e 100644
--- a/src/font.c
+++ b/src/font.c
@@ -3314,6 +3314,10 @@ font_open_for_lface (struct frame *f, Lisp_Object entity, Lisp_Object *attrs, Li
             pt = XFIXNUM (attrs[LFACE_HEIGHT_INDEX]);
           else
             {
+              /* We need the default face to be valid below.  */
+              if (FRAME_FACE_CACHE (f)->used == 0)
+                recompute_basic_faces (f);
+
               struct face *def = FACE_FROM_ID (f, DEFAULT_FACE_ID);
               Lisp_Object height = def->lface[LFACE_HEIGHT_INDEX];
               eassert (FIXNUMP (height));