bug#68940: 29.2; Random crashes in face for char / font

[Gerd Möllmann]

Robert Vojta <rvojta@me.com> writes:

> Sorry for the noise so far, this randomness drives me crazy, and the
> only thing exhibiting it is Emacs, rest is doing fine.

I feel with you :-). There have been, and still are, strange things
happening with GUI Emacs on macOS. Although, I think it has improved
a lot over the last year or two.

Whatever. Some other ideas:

- Maybe configuring with --enable-checking can find something? That
  enables a number of asserts in the code, among them things that ASAN
  can't find.

- If it's a font thing, Font Book could be used to validate the font in
  question. Select the font in Font Book and use File > Validate
  Selection.

- One of my pet peeves: nsterm.m contains calls to C function
  redisplay(), which is known to be problematic, although I didn't have
  seens downright crashes from this yet. The problem is that such
  redisplays can clear the face cache in settings where this isn't
  expected. Maybe it's worth commenting out the calls and see if that
  makes a difference, phenomenologically. That's only a shot in the
  dark, though, only based on the crashes being in some face-related
  stuff.