Unique user and group names validation (was: Re: Backward incompatible changes in mpd-service-type)

[Maxim Cournoyer]

+CC guix-devel, Jonathan

Hi Liliana,

Liliana Marie Prikler <liliana.prikler@gmail.com> writes:

> Am Montag, dem 06.03.2023 um 20:13 -0500 schrieb Maxim Cournoyer:
>> > Am Freitag, dem 17.02.2023 um 07:53 -0500 schrieb Maxim Cournoyer:
>> > > Else an error rather than a warning when multiple same-name users
>> > > are defined would be more appropriate, I think.
>> > Guess what, it used to be a formatted message (i.e. an actual
>> > error).  However, that broke some configs as reported in [1], so I
>> > demoted it to a warning.
>> 
>> Interesting.  I didn't know we were usefully (?) abusing duplicate
>> users and group.
> As far as I'm aware, we aren't.  Even if such uses exist, they raise
> said warning and probably cause more issues down the line, like with
> your bug report.
>
>> Perhaps we should try to isolate the most common offenders
>> (services?), fix them up, and then re-introduce the check, perhaps
>> gradually (e.g. "in 6 months time, duplicated users or groups will
>> become a configuration error").
> The only instance known to me (cups creating a duplicate lp group) was
> fixed back in 2021.

I'm starting a new discussion about it on guix-devel with the hope we
can better our understanding of which configurations would be broken if
8488f45b6e05d646224cc2b410497ddf9864c612 was re-instated, which seems
like a good idea to me?

-- 
Thanks,
Maxim