bug#67900: 30.0.50; Emacs Crahes When Executing Command `consult-buffer'

[Eli Zaretskii <eliz@gnu.org>]

> From: Chang Xiaoduan <drcxd@sina.com>
> Date: Tue, 19 Dec 2023 15:48:18 +0800
> 
> 
> Recently I frequently expericence Emacs crashes when executing the
> command `consult-buffer'. Though it is a command provided by a
> third-party package, I assume Emacs should report an lisp error rather
> than crashing? So I consider report this issue to GNU rather than author
> of some emacs-lisp package. As you can see I am using Emacs on Windows
> and I copmiled it from source using MinGW-w64. However, the same crash
> happens with a pre-built 29.1 Emacs downloaded from a mirror site.

The backtrace says that all-completions was called in a way that
either its first or its second argument are/include an invalid data,
whch doesn't produce a valid string.  How this could happen is
anybody's guess, because the backtrace you show is quite deep and
includes 3rd-party code.

We need a reproducible recipe, starting from "emacs -Q", to reproduce
the problem, so we could debug it here and find the reason(s).  Can
you please provide such a recipe?  It is okay to include in the recipe
commands that load add-on packages, as long as you clearly tell where
to get those packages and how to load them.

Thanks.