bug#42688: Running a script with `guix repl` doesn't "see" additional channels using (%package-module-path)

[Leo Prikler <leo.prikler@student.tugraz.at>]

Hi Ludo,
Am Donnerstag, den 17.09.2020, 17:31 +0200 schrieb Ludovic Courtès:
> Hi Leo,
> 
> [...]
> 
> ‘scm_program_arguments_fluid’ is marked as SCM_INTERNAL, so it’s
> really
> inaccessible.
Thought so.

> However, perhaps we could save the initial value of (program-
> arguments)
> in (guix ui) and use that in (guix describe)?
I'd personally put it in (guix describe) and use the same autoload
trick, that you've now used for %package-module-path (or a dedicated
save-...-excursion).  (guix ui) has a heavy closure for (guix describe)
to pull.

> > On the other hand, we could patch `guix repl` to initialize
> > %package-
> > module-path earlier (still leaving `guix describe` broken) or
> > somehow
> > try to work around that issue in `guix describe`.
> 
> Initializing (%package-module-path) earlier sounds like a good idea
> too,
> maybe like this:
> 
> [...] 
> 
I haven't tested that yet (pre-inst-env makes it so Guix doesn't have
any channels anyway), but yeah, something like that would have been my
idea.

Regards,
Leo