bug#9495: 24.0.50; Segfault in try_cursor_movement

[Eli Zaretskii]

> From: Leo <sdl.web@gmail.com>
> Cc: Eli Zaretskii <eliz@gnu.org>,  9495@debbugs.gnu.org
> Date: Thu, 15 Sep 2011 11:12:32 +0800
> 
> On 2011-09-15 03:50 +0800, Johan Bockgård wrote:
> > emacs -Q -eval '(setq line-move-visual nil truncate-lines t track-eol t)'
> >
> > C-u 100 x RET
> > y <up>
> >
> > At this point, in try_cursor_movement, point is in the "x" line, the
> > window has not yet hscrolled, and the value of hpos is just after the
> > last valid element in glyphs[TEXT_AREA].
> >
> > (It only actually crashes some of the time, of course.)
> 
> Does this happen with emacs-23? FWIW, I cannot get emacs-23 to crash.

It cannot possibly happen with Emacs 23, because this code is part of
the changes introduced in Emacs 24 for supporting display of
bidirectional text.

IOW, it's my fault ;-)