bug#67250: builtin:git-download capability detection not working for the bordeaux build farm

[Simon Tournier]

Hi,

On Wed, 22 Nov 2023 at 11:19, Ludovic Courtès <ludo@gnu.org> wrote:

> As in:
>
>   (open-connection
>     #:assume-available-builtin-builders '("download"))

Instead, why not check in ’git-fetch’?  Currently, the test is done
against the local daemon, right?

--8<---------------cut here---------------start------------->8---
(define* (git-fetch ref hash-algo hash
                    #:optional name
                    #:key (system (%current-system))
                    guile git)
  "Return a fixed-output derivation that fetches REF, a <git-reference>
object.  The output is expected to have recursive hash HASH of type
HASH-ALGO (a symbol).  Use NAME as the file name, or a generic name if #f."
  (mlet %store-monad ((builtins (built-in-builders*)))
    (if (member "git-download" builtins)
        (git-fetch/built-in ref hash-algo hash name
                            #:system system)
        (git-fetch/in-band ref hash-algo hash name
                           #:system system
                           #:guile guile
                           #:git git))))
--8<---------------cut here---------------end--------------->8---

For example, why not a test as:

    (if (and SOMETHING
             (member "git-download" builtins))

And this SOMETHING could be a global variable, as
%assume-builtin-builder, set to true by default and turn to false with
an environment variable, as GUIX_ASSUME_BUILTIN.


Cheers,
simon