Crash in bidi.c in Haiku port

Crash in bidi.c in Haiku port

[Po Lu]

Recently I experienced this abort twice in my Haiku port when
redisplaying a compilation buffer.

The abort happens at line 3363 of bidi.c, in this snippet of
bidi_find_other_level_edge:

      /* If we are at end of level, its edges must be cached.  */
      if (end_flag)
	emacs_abort ();

I can't seem to reproduce it reliably at all, and I haven't managed to
reproduce it in upstream Emacs, but if someone knows what might be wrong
here it would be appreciated.

Unfortunately, I haven't been able to save a core dump, as GDB
generate-core-file doesn't work on Haiku.

If you need any more information to debug this, let me know.  TIA.

Re: Crash in bidi.c in Haiku port

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Date: Wed, 22 Sep 2021 11:24:54 +0800
> 
> Recently I experienced this abort twice in my Haiku port when
> redisplaying a compilation buffer.
> 
> The abort happens at line 3363 of bidi.c, in this snippet of
> bidi_find_other_level_edge:
> 
>       /* If we are at end of level, its edges must be cached.  */
>       if (end_flag)
> 	emacs_abort ();

Very hard to say without more details.  Like whether this was the
first character of a buffer/string for which the function
bidi_move_to_visually_next was called, what kind of object (buffer,
string, composition, something else) we were iterating, what is the
contents of the bidi_cache, etc.

A reproducer is best, of course.