bug#43893: [PATCH] maint: update-guix-package: Ensure sources are clean.

[Ludovic Courtès]

Hi,

Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:

> By using a fresh copy of the last commit, we ensure the computed hash is
> stable in the face of local edits.  This change also computes the hash
> externally from the store, which allows to verify that the hashes are valid
> using, e.g.:
>
>  #FIXME: This doesn't work (recursion?)
> ./pre-inst-env guix build guix --with-git-url=guix=file://$PWD

Works for me, please open a separate bug report.  :-)

> * build-aux/update-guix-package.scm (git-add-worktree): New procedure.
> (main): Use it to checkout a clean copy of the used commit, and compute the
> hash from it.  Print a user warning after completion.

I’m not quite enthusiastic about the tool creating a worktree behind my
back.

> -         ;; Re-add SOURCE to the store, but this time under the real name 
> used
> -         ;; in the 'origin'.  This allows us to build the package without
> -         ;; having to make a real checkout; thus, it also works when working
> -         ;; on a private branch.

So this preserves this possibility, right?

> +            (format #t "Updated Guix to commit ~s.  You must ensure this
> +commit hash exists in the public repository, else 'guix pull' will break.
> +Beware of 'git rebase'~%" commit))))))

I think this is the most important bit.  :-)

I could also suggest running ‘guix build guix --check’.

Honestly, I would simply add this last message; better yet, we could use
Guile-Git to (1) check whether we’re on a dirty tree and stop right away
if we are, and (2) check whether the commit exists in the official Git
repo and error out if it doesn’t, unless
GUIX_ALLOW_ME_TO_USE_PRIVATE_COMMIT is set.

#2 could also be implemented by building the derivation of
(package-source guix) in ‘check’ mode (perhaps easier).

WDYT?

Thanks for looking into it, experience has shown that this really needs
to be addressed!

Ludo’.