Leo,

Leo Famulari wrote on 06/12/17 at 04:18:
> I think of "run-time references" as explicit store references
> (file-names) found in the build output by the post-build reference
> scanner and recorded in /var/guix/db. These references are what grafting
> rewrites.

All right, that was my idea too (though there might be some sloppiness
in my mental model yet).

> `guix gc --references` can be used to query the database for a given
> store item.
>
> `guix graph`, on the other hand, shows the graphs of package
> definitions. That is, the list of inputs, native-inputs,
> propagated-inputs, etc. Some of these inputs could be totally
> superfluous, and the build output would ideally not contain any
> explicit references to them at all.

Thanks for the clarification! I've never actually found a use for ‘guix
graph’ myself, but can't imagine a Guix talk without it. :-)

Unfortunately, I sent you after a red herring: ‘graph’ was a typo.
I did, in fact, mean ‘guix gc’:

  $ guix gc --references `guix build ghc` | grep perl
  /gnu/store/9g4fpfz86vjkx83v5696vm5dzg2sc9qj-perl-5.26.0
  $ grep -r /gnu/store/9g4fpfz86vjkx83v5696vm5dzg2sc9qj-perl-5.26.0 \
    `guix build ghc`
  .../ghc-split:#!/gnu/store/...-perl-5.26.0/bin/perl
  .../settings: ("perl command", "/gnu/store/...-perl-5.26.0/bin/perl"),

And:

  $ guix gc --references `guix build ghc-haddock-library` | grep hspec-d
  /gnu/store/xfh89fmdn2xvd4aw76164zqz0941xw01-hspec-discover-2.2.0
  $ grep -r xfh89fmdn2xvd4aw76164zqz0941xw01-hspec-discover-2.2.0 \
    `guix build ghc-haddock-library`
  [very long paths snipped with great prejudice]
  Binary file /gnu/store/.../package.cache matches
  Binary file /gnu/store/.../libHShaddock-library-1.2.1-...-ghc7.10.2.so
  matches

> The term "reference" has a few meanings in Guix, but I think that Mark
> is talking about explicit store paths.

I'm afraid we're on the same page then.

Kind regards,

T G-R