bug#12426: 24.2.50; Emacs is closed unexpectedly after query-replace

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 14 Sep 2012 16:35:08 +0400
> From: Dmitry Antipov <dmantipov@yandex.ru>
> CC: Richard Stallman <rms@gnu.org>, dmoncayo@gmail.com, 
>  12426@debbugs.gnu.org
> 
> On 09/13/2012 08:47 PM, Eli Zaretskii wrote:
> 
> > But marker_position and marker_byte_position are simple getters of
> > these two attributes of a marker.  If these attributes can be out of
> > range for some window of time, then the getters shouldn't enforce this
> > limitation.  Otherwise, they are getters that cannot be used in some
> > situations, which is IMO bad SE.  At the very least that should be
> > documented.
> 
> IIUC no, since this window of time is very short and it's entirely
> within adjust_markers_for_* functions.

The length of the window has no importance whatsoever.  It just takes
a couple of machine instructions to trigger the assertion violation.

This isn't a stock exchange or a poker game, where we could build on
chances.  This is software that is supposed to be stable, and you are
talking about its most inner and intimate internals.

If you can figure out how to avoid the crash, please do.  Otherwise,
please remove the eassert calls, because they make Emacs completely
unusable.