bug#41182: Profile hooks ignore system and target

[Ludovic Courtès]

Hello!

As janneke found (and maybe Mathieu also), the profile hooks called by
‘profile-derivation’ for some reason end up using a different system and
target, as can be seen in this example:

--8<---------------cut here---------------start------------->8---
$ guix describe
Generacio 141   May 10 2020 11:41:44    (nuna)
  guix 279569c
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: 279569ca8251b9ae3f96e4486e4614e340d0fe4f
$ guix pack --target=arm-linux-gnueabihf --no-grafts idutils -d
/gnu/store/rjbs4a5l1vi3winbf71xz3d0hhmdwnjj-tarball-pack.tar.gz.drv
$ guix gc -R 
/gnu/store/rjbs4a5l1vi3winbf71xz3d0hhmdwnjj-tarball-pack.tar.gz.drv | grep 
idutils-4.6.drv
/gnu/store/kfv7bwzapb3lfirdpyjh5zcrrpld90ni-idutils-4.6.drv
/gnu/store/1y5rjcvs6giag414wg4ngz7cp4mxy76v-idutils-4.6.drv
$ guix build idutils --no-grafts -d
/gnu/store/kfv7bwzapb3lfirdpyjh5zcrrpld90ni-idutils-4.6.drv
$ guix build idutils --no-grafts -d --target=arm-linux-gnueabihf
/gnu/store/1y5rjcvs6giag414wg4ngz7cp4mxy76v-idutils-4.6.drv
--8<---------------cut here---------------end--------------->8---

We should be seeing only the cross-compile derivation.  Where does the
native derivation come from?

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix graph --path -t derivation 
/gnu/store/rjbs4a5l1vi3winbf71xz3d0hhmdwnjj-tarball-pack.tar.gz.drv 
/gnu/store/kfv7bwzapb3lfirdpyjh5zcrrpld90ni-idutils-4.6.drv
/gnu/store/rjbs4a5l1vi3winbf71xz3d0hhmdwnjj-tarball-pack.tar.gz.drv
/gnu/store/hxp1gqbmmq4hjwnb8m1amp15k0ax455m-profile.drv
/gnu/store/3180cdca49sl6xhn9prx9xcwv20jlpdl-fonts-dir.drv
/gnu/store/kfv7bwzapb3lfirdpyjh5zcrrpld90ni-idutils-4.6.drv
--8<---------------cut here---------------end--------------->8---

Actually all the profile hooks refer to the native derivation.

To be continued…

Ludo’.