Re: emacs-27 41232e6: Avoid crashes due to bidi cache being reset during redisplay

[Pip Cet]

On Sun, May 31, 2020 at 3:46 PM Eli Zaretskii <eliz@gnu.org> wrote:
> > From: Pip Cet <pipcet@gmail.com>
> > Date: Sun, 31 May 2020 15:36:22 +0000

> > Sorry, should have been more explicit: if we run out of memory,
> > memory_full will signal an error, after freeing some "spare" memory.
> > The error handler will call echo_display_area_1. If the bidi iterator
> > is in use, the cache size is much larger than the spare memory we
> > freed, so the allocation will also fail, and I'm not sure we ever
> > recover from that.
> Yes, our code is full of such places.  It would be good to improve the
> recovery in these cases.

I've played around a little, and when resize-mini-windows is nil, it's
quite easy to get into a loop where the OOM message isn't displayed.
Without the patch, recovery sometimes works. Maybe it's just time to
update SPARE_SIZE to reflect the amount of memory the bidi iterator
currently needs.