Subject: Re: [bug#36738] [PATCH] guix deploy: Support '--no-grafts' and '--system'

From: [email-masked] (Jakob L. Kreuze)
Date: Tue, 23 Jul 2019 15:33:20 -0400

Hi Chris,

Christopher Lemmer Webber <[email-masked]> writes:

> Maybe a good idea... let me think. Is there any case where we start
> taking actions *before* we might probe a machine that we can think of?
>
> How would we also probe it? Is there a chance of our probing behaving
> incorrectly? That would also be bad, if so.

None that come to mind right now, and if there are any, I don't think
they would be affected by the probing -- aside from doing work that
would get thrown out when the script errors out.

As for the safety of probing, none of the tests I intend on implementing
are effectful. It would be equivalents for 'check-mapped-devices',
'check-file-system-availability', and 'check-initrd-modules', all of
which do little beyond looking at the devices available on the system,
and now a check that would read '%current-system'.

> Another route is to have the user specify what architecture they think
> the machine has, and instead the probing is a "safety check"?

That'd work too, but I feel it's better to avoid putting an unnecessary
burden on the user.

Regards,
Jakob