From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: [PATCH 07/17] gnu: linux-libre: Use make-linux-libre.
Date: Sun, 11 Sep 2016 23:07:50 +0200
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References: <20160909013641.GA9202@jasmine>
	<20160909123426.18499-1-david@craven.ch>
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In-Reply-To: <20160909123426.18499-7-david@craven.ch> (David Craven's message
	of "Fri, 9 Sep 2016 14:34:16 +0200")
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To: David Craven <david@craven.ch>
Cc: guix-devel@gnu.org

David Craven <david@craven.ch> skribis:

> * gnu/packages/linux.scm (linux-libre, linux-libre-4.4,
>   linux-libre-4.1): Use make-linux-libre.
>   (make-linux-libre): New variable.

[...]

> +(define-public linux-libre
> +  (let* ((version "4.7.2")
> +         (conf (kernel-config
> +                (or (%current-target-system)
> +                    (%current-system))
> +                #:variant (version-major+minor version))))

I just realized that this won=E2=80=99t do what we want.

The expression (or (%current-target-system) (%current-system)) is
evaluated at the top-level=E2=80=94i.e., when (gnu packages linux) is loade=
d.
At that time, (%current-system) holds its default value and
(%current-target-system) is #f.  IOW, even if you do:

  guix build -s foo linux-libre

or:

  guix build --target=3Dbar linux-libre

you always end up with the x86_64-linux kernel config (if you=E2=80=99re on
x86_64-linux).

Conversely, when we write:

  (package
    ;; =E2=80=A6
    (inputs `(("conf" ,(kernel-config
                         (or (%current-target-system) =E2=80=A6))))))

things work as expected because the =E2=80=98inputs=E2=80=99 field is =E2=
=80=9Cthunked=E2=80=9D
(lazy-evaluated) specifically for this purpose.

A solution would be to pass a procedure instead of a config:

  (define* (make-linux-libre version hash
                             #:key
                             (configuration-file #f)
                             (defconfig "defconfig"))
    (package
      (name "linux-libre")
      (version version)
      (source (origin
                (method url-fetch)
                (uri (linux-libre-urls version))
                (sha256 (base32 hash))
                (patches (origin-patches %boot-logo-patch))))
      (build-system gnu-build-system)
      (supported-systems '("x86_64-linux" "i686-linux"))
      (inputs
       `(("bc" ,bc)
         ;; =E2=80=A6
         ;; Call =E2=80=98configuration-file=E2=80=99 and pass it the right=
 system type.
         ,@(if configuration-file
               `(("kconfig" ,(configuration-file
                              (or (%current-target-system) =E2=80=A6))))
               '())))

   (define variant1
      (make-linux-libre v h
                        #:configuration-file (lambda (system)
                                               =E2=80=A6)))

Makes sense?

HTH!

Ludo=E2=80=99.