Re: 02/09: guix: store: Make register-items transactional, register drv outputs

[Caleb Ristvedt <caleb.ristvedt@cune.org>]

> A problem is that we should not pull in these two modules here, because
> they are conceptually at a higher level (they have to do with talking to
> a separate daemon process.)
>
> So perhaps a first step would be to re-arrange things, probably along
> these lines:
>
>   • Move the .drv parsing code and the <derivation> record type from
>     (guix derivations) to, say, (guix store derivations).
>
>   • Re-export all these bindings from (guix derivations).
>
>   • Move ‘store-path?’, ‘derivation-path?’ & co. (everything below line
>     1745 in guix/store.scm) to, say, (guix store files).  Re-export
>     appropriately so the API remains unchanged.
>
> At this point, (guix store …) modules won’t have to use (guix store) and
> (guix derivations) at all.
>
> How does that sound?

As we found out on IRC yesterday, https://bugs.gnu.org/15602 is causing
this to fail. If I understand correctly, the workaround involves trying
to make sure that modules that use (guix memoization) are compiled
before (guix memoization) is (and it turns out that once that's solved
the same issue occurs with (guix config)). Considering that the
module-import-compiled builders just do a depth-first-search for scheme
source files ordered alphabetically, that's a bit tricky. I ended up
making a dummy module, (gnu build dummy), that does nothing but use
(guix config) and (guix memoization), and the tests now pass.

Does a better workaround exist? Could we pass an ordered list of files
to the builder somehow instead of just a directory? But then again,
changing every module-import-compiled would mean rebuilding the
world. Eh.

Thoughts?

Oh, also, should I just copy all the copyright lines from the old
modules to the new ones?

- reepca