Re: struct face question

[Eli Zaretskii <eliz@gnu.org>]

> From: Po Lu <luangruo@yahoo.com>
> Cc: emacs-devel@gnu.org
> Date: Fri, 16 Sep 2022 15:31:47 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> leading to face_for_char aborting from face->fontset being -1 later on.
> >
> > Please show a full backtrace from the crash, and preferably also a
> > reproducer.  What character are we trying to display in that case?
> 
> In that specific case, a newline character.  But the problem can also be
> easily reproduced with the following code:
> 
>   (insert (propertize "foo" 'face '(:height 0.1)))
> 
> as long as no core font of that height is installed.

The assertion that triggers is too early: we don't use the fontset
information before this part:

  fontset = FONTSET_FROM_ID (face->fontset);
  eassert (!BASE_FONTSET_P (fontset));

So does the problem go away if you move the assertion before the first
of these two lines?