bug#63869: [shepherd] `guix system reconfigure` forgets `herd disable mysrv`

[Maxim Cournoyer]

Hi Ludovic,

Ludovic Courtès <ludo@gnu.org> writes:

> Attila Lendvai <attila@lendvai.name> skribis:
>
>> i turn off some services using `herd disable`. then i do a `guix
>> system reconfigure`, and these services get enabled and started.
>>
>> i would expect the enabled/disabled state to be preserved across 
>> reconfigures.
>
> When a service is stopped at the time of reconfigure, it is immediately
> replaced and then started.
>
> Replacing works by unregistering the old instance from the registry and
> registering a new one.  As a side effect, you end up with an instance
> that’s enabled (see ‘service-registry’ in (shepherd services)).
>
> I never thought it could be a problem.  WDYT?

I think it probably goes against users' expectation (i.e., systemd) that
a disabled service stays disabled unless manually re-enabled (I think
that's the way it is for systemd, even when the system is upgraded?).

If we want Guix/Shepherd to differ from this common expectation (on the
ground that declarative should prevail over state, maybe?), it'd be good
to have at least this documented/explained somewhere.

What do you think?

-- 
Thanks,
Maxim