bug#42410: Copying nars between stores fails for packages with multiple outputs

[Ludovic Courtès]

Hi,

Leo Famulari <leo@famulari.name> skribis:

> Exporting a nar and importing it on another machine only works when the
> package being built has a single output.

Note that “guix archive --export foo” only exports foo:out.  If you want
to export other outputs, you have to explicitly list them.

> I set up a signing-key on the sending machine, authorized it on the
> receiving machine, and successfully transferred some nars of
> single-output packages. I say they succeeded because `guix build
> --no-grafts foo` did not need to build foo after having imported the nar
> archive built on the other machine.

‘guix build’ starts building unless all the outputs of the package are
already in the store.

> However, it fails for packages with multiple outputs such as Syncthing
> and libsmf.

Could it be that you copied only one output of the package, and thus
‘guix build’ considered it had to build it because the other outputs
were missing?

Thanks,
Ludo’.