Subject: bug#30874: 27.0.50; Emacs crashes

From: Robert Pluim <[email-masked]>
Date: Mon, 26 Mar 2018 18:52:17 +0200

Eli Zaretskii <[email-masked]> writes:

>
> Thanks, this is what I suspected.
>
> But now that I actually see it, I don't think I understand the reason:
> the call to XftTextExtents8 asks the xft font back-end to produce the
> extents for an all-ASCII string, so the fact that it may not have
> glyphs for some exotic non-ASCII characters couldn't be the culprit.

OK. Is it possible that because we're in synchronous mode that the
signal has been received just at an inopportune moment? I'll rerun the
test and let it sit for a longer time to see if it changes anything.

> Also, if you replace #x274c in the original recipe with an ASCII
> codepoint, it doesn't crash, does it?  Yet I'd expect to see exactly
> the same call to XftTextExtents8 in xftfont_open in that case.

It doesn't crash if I do eg (insert-char ?a), nor (insert-char #x700).

> Can you figure out what's going on here, and why?

Looks like I'll have to go poking around in the guts of Xft. Pointers
appreciated.

Robert