bug#36431: Crash in marker.c:337

[Eli Zaretskii]

> Date: Wed, 03 Jul 2019 08:20:23 +0200 (CEST)
> Cc: eliz@gnu.org, 36431@debbugs.gnu.org
> From: Werner LEMBERG <wl@gnu.org>
> 
> > Here's an alternative patch which doesn't suffer from this problem
> > but also eliminates the transiently-inconsistent multibyte buffer
> > situation.
> 
> Thanks for the patch.  It partially works: One crash is avoided that I
> get without it, but another crash appears every time I want to send an
> e-mail with `mew'; see the attached backtrace.

Werner,

PLEASE try to prepare a reproduction recipe as I suggested earlier.
Without that, debugging this problem is going to be very inefficient,
and we will not be able to tell for sure we fixed it even if you
report that your particular use case no longer triggers assertions.

TIA

P.S. I also think your sources are out of sync with the current
master, which is another factor that makes debugging harder and more
error-prone.  Can you update from master, please?