Fix rare crashes in redisplay due to problems with fontsets

* src/xdisp.c (get_next_display_element): If we have no usable
face to display a character/composition, treat that as glyphless.
(produce_glyphless_glyph): If neither it->face nor its ASCII face
are usable, fall back to the frame's default font.  (Bug#65198)
This commit is contained in:
Eli Zaretskii 2023-08-12 09:38:28 +03:00
parent b1ba06a1e4
commit 03e897c08f

View file

@ -8312,9 +8312,17 @@ get_next_display_element (struct it *it)
&& success_p
&& FRAME_WINDOW_P (it->f))
{
struct face *face = FACE_FROM_ID (it->f, it->face_id);
struct face *face = FACE_FROM_ID_OR_NULL (it->f, it->face_id);
if (it->what == IT_COMPOSITION && it->cmp_it.ch >= 0)
/* It shouldn't happen, ever, that FACE is NULL here, but
evidently some faulty fonts/fontsets can sometimes cause it.
In that case, we punt and consider the stuff undisplayable. */
if (!face)
{
it->what = IT_GLYPHLESS;
it->glyphless_method = GLYPHLESS_DISPLAY_EMPTY_BOX;
}
else if (it->what == IT_COMPOSITION && it->cmp_it.ch >= 0)
{
/* Automatic composition with glyph-string. */
Lisp_Object gstring = composition_gstring_from_id (it->cmp_it.id);
@ -31781,9 +31789,12 @@ produce_glyphless_glyph (struct it *it, bool for_no_font, Lisp_Object acronym)
int len;
/* Get the metrics of the base font. We always refer to the current
ASCII face. */
face = FACE_FROM_ID (it->f, it->face_id)->ascii_face;
font = face->font ? face->font : FRAME_FONT (it->f);
ASCII face, but if some faulty setup of fontsets causes that to
be NULL, we fall back to the frame's default font. */
face = FACE_FROM_ID_OR_NULL (it->f, it->face_id);
if (face)
face = face->ascii_face;
font = (face && face->font) ? face->font : FRAME_FONT (it->f);
normal_char_ascent_descent (font, -1, &it->ascent, &it->descent);
it->ascent += font->baseline_offset;
it->descent -= font->baseline_offset;