Subject: Re: bug#64351: probabe bug associated with “completion-regexp-list”

From: Stefan Monnier <[email-masked]>
Date: Fri, 30 Jun 2023 15:02:07 -0400

>> Shynur> Evaluate this:
>> Shynur>     (setq completion-regexp-list '("^[^-]"))
>> Stefan> Bad idea.
>
> I have to say that it is not a bad idea to write this _meaningless_
> and _short_ expression.  I just want to find a short enough expression
> to show the issue.

FWIW, the main problem is setting this var while minibuffer.el functions
are called (so setting globally is definitely a problem).
This var is usually expected to be let-bound next to your own calls to
`try/all/test-completion`.

But as I say, this is actually not documented, it's just what I have
found to be general assumptions is various packages that implement
completion UIs (including the one I wrote :-)

> If I post a _long_ code snippet and say “Hey,
> there’s a bug”, nobody wants to see it. :-)

I know what you men.  I'd be interested to hear about your
use-case, tho.  Maybe I can provide a good alternative.

        Stefan