Re: The `channels' field of `operating-system' record

[Ludovic Courtès]

Hi,

Tomas Volf <~@wolfsden.cz> skribis:

> On 2024-04-10 17:17:27 +0200, Ludovic Courtès wrote:

[...]

>> Yes, why is that?  At first sight, that’s because ‘extra-special-file’
>> does things at activation time; there’s no check happening at
>> configuration time.
>>
>> It was really meant for /bin/sh, /usr/bin/env, and similar.  The reason
>> its effect is silently dismissed in this case is, I think, because its
>> activation runs before the /etc activation.  So it’s really bad luck.
>>
>> I’m not sure what to do here, apart from maybe recommending against
>> broad use of this service.
>
> I will re-phrase the above into a documentation patch.

Great.

>> That would be: (guix-configuration … (channels (load "channels.scm"))).
>
> That does not seems to work, I am getting this error:
>
>     /tmp $ guix system build os.scm
>     ;;; compiling /tmp/channels.scm
>     ;;; /tmp/channels.scm:1:7: warning: possibly unbound variable `channel'

[...]

> But after some experimentation (and looking into pull.scm), it seems what I 
> need
> is this:
>
>     (use-modules (guix ui))
>     (use-modules (guix channels))
>
> and
>
>     (channels (load* "channels.scm"
>                      (make-user-module '((guix channels)))))

Or simpler: use (guix channels) in your OS config so you can use
(load "channels.scm").

(‘load’ evaluates code in the current module.)

> Maybe it would be best to extract (load-channels) from pull.scm into
> guix/channels.scm, exporting it?  (Since for example the above is missing 
> error
> checking code from (load-channels)).

Yes, good idea, we can do that.

Thanks for your feedback!

Ludo’.