bug#51321: 29.0.50; date in modelines

[Filipp Gunbin]

On 01/11/2021 21:17 +0000, Alan Third wrote:

> On Mon, Nov 01, 2021 at 04:34:58PM +0200, Eli Zaretskii wrote:
>> > From: Filipp Gunbin <fgunbin@fastmail.fm>
>> > Cc: alan@idiocy.org,  larsi@gnus.org,  nisoni@algon.dk,  stefan@marxist.se,
>> >   51321@debbugs.gnu.org,  mardani29@yahoo.es
>> > Date: Mon, 01 Nov 2021 17:21:36 +0300
>> >
>> > >> So maybe we should check that the locale is valid before setting it...
>> > >
>> > > "Valid" in what sense?  Is that locale not installed on your system,
>> > > or are you saying that it cannot exist?
>> >
>> > I think in the sense of 'locale -a | grep ru' in this case:
>> >
>> > ru_RU.ISO8859-5
>> > ru_RU.CP866
>> > ru_RU.CP1251
>> > ru_RU.UTF-8
>> > ru_RU.KOI8-R
>> > ru_RU
>> >
>> > Maybe it could exist, but it doesn't on macOS.
>> >
>> > > (And why does the warning come from Bash when it was Emacs who sets
>> > > the locale?)
>> >
>> > Forgot to tell - this output shows up when running shell command from
>> > emacs (M-! or similar).
>>
>> Hmm... actually, why do we call setenv instead of calling setlocale
>> directly?  Doesn't macOS support setlocale?  AFAIU, calling setlocale
>> would then only affect Emacs itself, not its sub-processes.
>
> The point of this is to affect Emacs's sub-processes.
>
> I know almost nothing about the locale, but from reading the man pages
> I can't understand why we need to set LC_ALL when we're already
> setting LANG. Isn't LANG the fallback if LC_ALL isn't set?
>
> Anyway, I think we can use setlocale to test if the locale string is
> valid, but I don't know if there are any other problems with that.
> Would we want to reset it after testing?
>
> I suppose it might also be preferable to not even try doing this if
> Emacs was run from a terminal since the original problem really only
> manifests when Emacs is run from the GUI.
>
> Fillip, can you please try this:
>
[..]

I see Daniel is saying that perhaps his patch should be reverted, so
please let me know if you still want me to test this.