bug#37637: 27.0.50; Segmentation fault when setting font face for new frames

[Andreas Hilboll]

> Thanks, please see if the patch below gives good results.
>
> diff --git a/src/font.c b/src/font.c
> index 935dd64..044c437 100644
> --- a/src/font.c
> +++ b/src/font.c
> @@ -3314,6 +3314,9 @@ 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));

Great, this seems to fix it.  Works without problems now (after opening 
~10 new frames without any crash I stopped ...).

Thanks for the quick help!