bug#50026: Specify a pull-request in --with-branch package transformations

[Ludovic Courtès]

Hi!

Philippe SWARTVAGHER <philippe.swartvagher@inria.fr> skribis:

> guix build chameleon --with-branch=chameleon=merge-requests/262/head
>
> ```
>
> (with 262 being the pull-request I'm interested in) However, this fails:
>
> ```
>
> guix build: erreur : impossible de récupérer la branche «
> merge-requests/262/head » depuis
> https://gitlab.inria.fr/solverstack/chameleon : cannot locate
> remote-tracking branch 'origin/merge-requests/262/head'
> ```
>
> While commands stated in the documentation work well:
>
> ```bash
>
> git clone https://gitlab.inria.fr/solverstack/chameleon && cd chameleon
>
> git fetch origin merge-requests/262/head:mr-262
>
> git checkout mr-262

Any idea what makes this branches “special” from a Git viewpoint?

Guix uses libgit2 (via Guile-Git); perhaps there’s a feature here that
libgit2 doesn’t support, or perhaps there’s an additional step to make
to make those branches visible?

Thanks,
Ludo’.