Subject: bug#43843: git-annex is not Reproducible

From: zimoun <[email-masked]>
Date: Mon, 12 Oct 2020 11:31:33 +0200

On Sat, 10 Oct 2020 at 11:34, Ricardo Wurmus <[email-masked]> wrote:

> > --8<---------------cut here---------------start------------->8---
> > 67cb9fa2357026ee42ec5bb0923ec4dc4a43abe2 is the first bad commit
> > commit 67cb9fa2357026ee42ec5bb0923ec4dc4a43abe2
> > Author: Ricardo Wurmus <[email-masked]>
> > Date:   Tue Jun 16 22:25:48 2020 +0200
> >
> >     build-system/haskell: Support parallel builds.
> >
> >     * guix/build-system/haskell.scm (haskell-build): Add keyword
> >       PARALLEL-BUILD?
> >     and pass it on to the builder.
> >     * guix/build/haskell-build-system.scm (build): Accept keyword
> >       PARALLEL-BUILD?
> >     and pass the number of parallel jobs to GHC.
> >
> >  guix/build-system/haskell.scm       | 2 ++
> >  guix/build/haskell-build-system.scm | 7 +++++--
> >  2 files changed, 7 insertions(+), 2 deletions(-)
> > bisect run success
> > --8<---------------cut here---------------end--------------->8---
>
> Shall we revert it?  Previously the build system also supported parallel
> builds, but didn’t seem to pass the right arguments to actually make it
> happen.

What do the Haskellers think about that?
Does the parallel build save a lot of time and CPU?  If yes, maybe we
could to provide a transformation for the expert, something like
"haskell-build-system-with-parellel-build" which tweaks
"PARALLEL-BUILD?", similarly to the recent "no tests".  WDYT?

All the best,
simon