[bug#47754] [PATCH] gnu: transformations: fix with-latest option for git source package.

[Z572 via Guix-patches via <guix-patches@gnu.org>]

zimoun <zimon.toutoune@gmail.com> writes:

> Hi,
>
> On Wed, 3 Nov 2021 at 16:34, Z572 <873216071@qq.com> wrote:
>
>> $ file `guix build fbreader --with-latest=fbreader -S`
>> /gnu/store/rdqkmjpiig9gddzsxj4mdyw8lvn944xg-FBReader: HTML document,
>> UTF-8 Unicode text, with very long lines
>
>> If a package is a git source package, after use "with-latest"
>> option, it's url
>> will become to it's source. and build will fail.
>>
>> This patch just fix this.
>
> I see.  However, I am not convinced your example is correct, because
> for instance,
>
> $ file $(guix build r-soupx -S)
> /gnu/store/1z0j6i4a9xwwd8d3955m7vq3f1x4p3aq-r-soupx-0.3.1-1.a3354be-checkout:
> directory
>
> What you are seeing is: Git upstream source is modified by Guix (for
> instance, patches are applied or files are removed; in the field
> 'origin') and "guix build -S" returns what Guix actually builds, not
> what upstream provides.  Therefore, in this case, the modified source
> is returned as compressed archive.  However, when using the
> transformation 'with-latest', in this case, "guix build -S
> --with-latest" returns what upstream provides, thus a directory (or
> something else as a file).

I looked source again, just because of "upstream-source-compiler" don't support
git source package, all will become to use url-fetch.

See (guix upstream) module:

``` scheme
(define-gexp-compiler (upstream-source-compiler (source <upstream-source>)
                                                system target)
  "Download SOURCE from its first URL and lower it as a fixed-output
derivation that would fetch it."
  (mlet* %store-monad ((url -> (first (upstream-source-urls source)))
                       (signature
                        -> (and=> (upstream-source-signature-urls source)
                                  first))
                       (tarball ((store-lift download-tarball) url signature)))
    (unless tarball
      (raise (formatted-message (G_ "failed to fetch source from '~a'")
                                url)))

    ;; Instead of returning TARBALL, return a fixed-output derivation that
    ;; would be able to re-download it.  In practice, since TARBALL is already
    ;; in the store, no extra download will happen, but having the derivation
    ;; in store improves provenance tracking.
    (let ((hash (call-with-input-file tarball port-sha256)))
      (url-fetch url 'sha256 hash (store-path-package-name tarball)
                 #:system system))))

```

I'm have no idea how to change it, so i just check if package is
git-source, use "git-checkout" instead of "upstream-source".

>
> Maybe I miss something, but from me, the inconsistency comes from the
> behavior of "guix build -S", not about the behaviour of 'with-latest'
> transformation.  And I also miss why the build would fail.
>
>
> Cheers,
> simon


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