Subject: Re: bug#79437: 30.2; world-clock silently and incorrectly parses invalid time zone

From: Paul Eggert <[email-masked]>
Date: Sat, 13 Sep 2025 21:55:07 -0700

On 2025-09-13 16:56, Jorge P. de Morais Neto wrote:

> Anyway, I see many possible solutions and workarounds:
> 
> 1. `world-clock' could check the timezone name is valid, and warn in
>     case it is not.
> 2. custom.el could validate `zoneinfo-style-world-list' when it is set.
> 3. The docstring of `zoneinfo-style-world-list' and `world-clock' could
>     warn the user about the problem.
> 
> I believe 3 should be implemented in any case.  Ideally it would be
> combined with 1, 2, or preferably both.

That all sounds reasonable, if someone else wants to implement and/or 
document it.