bug#48711: Crashes in lisp_string_width

[Eli Zaretskii]

> Date: Fri, 28 May 2021 10:11:35 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 48711@debbugs.gnu.org
> 
> Thanks, but I need a recipe to reproduce this, and/or at least some
> idea about which variables cause the problem.

But before you embark on providing that info, please try the latest
master branch, where I installed a stab-in-the-dark change which
hopefully could take care of whatever happened in your case.