bug#72570: 31.0.50; Regression in date-to-time

[Eli Zaretskii <eliz@gnu.org>]

> From: Ulrich Mueller <ulm@gentoo.org>
> Cc: Paul Eggert <eggert@cs.ucla.edu>,  72570@debbugs.gnu.org
> Date: Mon, 12 Aug 2024 14:51:02 +0200
> 
> > But that is not necessarily incorrect, because several time-conversion
> > functions, including those involved in this issue, don't document
> > their assumptions about time-zone when it is omitted.  This includes
> > parse-time-string and iso8601-parse.  Since these functions don't
> > document this aspect, and the code involved in the above snippet is
> > quite convoluted, it is hard for me to decide which part of what
> > function needs to be fixed.
> 
> Well, parse-time-string doesn't make any assumptions about the timezone.
> It will return a list with nil in its TZ element, if it cannot extract
> any timezone info from the string.
> 
> Same for iso8601-parse, the returned TZ is nil if it is not present in
> the argument string.

Yes, but what does nil as timezone mean, when you later interpret the
time values?  Is it UTC or is it local time?