Re: Recursively propagate build-system 'arguments' to dependency packages?

[Ricardo Wurmus]

Myles English <address@hidden> writes:

> Hello Fede, Eric,
>
> on [2017-02-07] at 15:15 Federico Beffa writes:
>
>> Eric Bavier <address@hidden> writes:
>>
>>> On Mon, 06 Feb 2017 21:09:33 +0000
>>> Myles English <address@hidden> wrote:
>>>
>>>> Trying to define a package to be compiled by ghc-8, and I think all of
>>>> its dependencies must also be compiled by ghc-8 rather than ghc (which
>>>> is version 7).  This is easy to do with one package, e.g..:
>>>>
>>>> (define-module (my-packages myhaskell)
>>>>  ...
>>>>   #:use-module ((gnu packages haskell) #:prefix haskellmain:))
>>>>
>>>> (define-public ghc-hunit8
>>>>   (package
>>>>     (inherit haskellmain:ghc-hunit)
>>>>     (arguments `(#:haskell ,ghc-8))))
>>>>
>>>> To do that recursively for all the dependencies seems Too Difficult so,
>>>> is there a way to do something like --with-input=ghc=ghc-8 but with the
>>>> build-system arguments?  Perhaps doing the work in between the Bag and
>>>> the Derivation?
>
> Thanks Eric for your suggestion. I made a start on this...
>
>>> You may take a look at the 'package-with-python2' procedure in
>>> guix/build-system/python.scm, which seems like it could be adapted to
>>> work with haskell/ghc packages.
>>
>> Hi Eric, Myles,
>>
>> it seems that the only Python specific part of
>> 'package-with-explicit-python' is the keyword '#:python'. What do you
>> think of generalizing it by making it a function keyword argument and
>> move the procedure to its own module (maybe (guix build-system
>> utils)?).
>
> ...I came the same conclusion as Fede: it could be generalised.  It is
> probably close to working for me (with respect to ghc) so I will keep
> going for now.  I am not competent enough to generalise it but if
> someone else does I can help test it.

I’m doing the same for some Perl packages.  I defined a procedure
“package-for-perl-5.14” which takes a package and rewrites it.

It looks like this:

--8<---------------cut here---------------start------------->8---
(define (package-for-perl-5.14 pkg)
  (let* ((rewriter (package-input-rewriting `((,perl . ,perl-5.14))
                                            perl-5.14-package-name))
         (new (rewriter pkg)))
    (package
     (inherit new)
     (arguments `(#:perl ,perl-5.14
                  ,@(package-arguments new))))))
--8<---------------cut here---------------end--------------->8---

The problem here is that it doesn’t rewrite the “#:perl” argument
recursively, so the dependencies of a Perl package will still refer to
the latest version of Perl as that’s what’s used in the build system.

We would need a solution that would take care of this problem for all
build systems.

--
Ricardo

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