Re: 01/03: guix: store: Add ensure-path.

[Mathieu Othacehe <othacehe@gnu.org>]

Hey,

> So perhaps we should adjust the docstring to reflect that?

Sure, done with: d9e57db72479812cfa30ed8e30a6351959f9a2b2.

> Yeah, ‘guix offload’ should not connect to the daemon.  It does so
> currently for one thing (registering GC roots IIRC), which should be
> done in Scheme instead.

Why shouldn't it connect to the daemon? In the current implementation of
the nix daemon, there's the following snippet:

--8<---------------cut here---------------start------------->8---
        if (!missing.empty()) {
            Activity act(*logger, lvlTalkative, actUnknown, fmt("copying outputs from '%s'", storeUri));
            for (auto & i : missing)
                store->locksHeld.insert(store->printStorePath(i)); /* FIXME: ugly */
            copyPaths(ref<Store>(sshStore), store, missing, NoRepair, NoCheckSigs, NoSubstitute);
        }
--8<---------------cut here---------------end--------------->8---

in build-remote.cc. So it looks like it connects to the store, add the
outputs to locks held and import them, which is the behaviour I'm
trying to replicate.

> Specifically it handles “nar bundles” (new name :-)).  But probably you
> can extract the relevant bits to import single nars, right?

Yup you're right, it should be possible, but I'd rater let the daemon do
it if possible.

Thanks,

Mathieu