From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: Proposal: prefetch tarballs in a batch
Date: Wed, 02 Apr 2014 14:57:09 +0200
Message-ID: <87ha6blwii.fsf@gnu.org>
References: <87ha6jkyv8.fsf@karetnikov.org> <877g7epico.fsf@gnu.org>
	<87wqf8prau.fsf@karetnikov.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Return-path: <guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org>
Received: from eggs.gnu.org ([2001:4830:134:3::10]:33997)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <ludo@gnu.org>) id 1WVKjH-0006Ar-V0
	for guix-devel@gnu.org; Wed, 02 Apr 2014 08:57:25 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <ludo@gnu.org>) id 1WVKjC-0007Lc-Np
	for guix-devel@gnu.org; Wed, 02 Apr 2014 08:57:19 -0400
Received: from hera.aquilenet.fr ([2a01:474::1]:56230)
	by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from <ludo@gnu.org>)
	id 1WVKjC-0007LD-Ht
	for guix-devel@gnu.org; Wed, 02 Apr 2014 08:57:14 -0400
In-Reply-To: <87wqf8prau.fsf@karetnikov.org> (Nikita Karetnikov's message of
	"Wed, 02 Apr 2014 03:23:53 +0400")
List-Id: "Development of GNU Guix and the GNU System distribution."
	<guix-devel.gnu.org>
List-Unsubscribe: <https://lists.gnu.org/mailman/options/guix-devel>,
	<mailto:guix-devel-request@gnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/archive/html/guix-devel>
List-Post: <mailto:guix-devel@gnu.org>
List-Help: <mailto:guix-devel-request@gnu.org?subject=help>
List-Subscribe: <https://lists.gnu.org/mailman/listinfo/guix-devel>,
	<mailto:guix-devel-request@gnu.org?subject=subscribe>
Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org
Sender: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org
To: Nikita Karetnikov <nikita@karetnikov.org>
Cc: guix-devel@gnu.org

Nikita Karetnikov <nikita@karetnikov.org> skribis:

>> The simplest way to do it would be by walking the package DAG: start
>> from =E2=80=98foo=E2=80=99, accumulate its =E2=80=98package-source=E2=80=
=99, then traverse its inputs,
>> etc.  Recursion would stop at the implicit inputs (GCC, glibc,
>> Coreutils, etc.), though.
>
>> If you=E2=80=99d like implicit inputs to be taken into account, then you=
=E2=80=99d have
>> to traverse derivations.  It=E2=80=99s less convenient because it=E2=80=
=99s lower-level.
>
> Is there a function that accepts a package name and returns a list of
> implicit inputs?

No, because by definition, those =E2=80=9Cimplicit inputs=E2=80=9D are not =
listed in the
package object.  Instead, they are added by the build system (see
build-system/gnu.scm.)

That=E2=80=99s why I suggested using derivations instead: take the output of
(package-derivation x y), and traverse it in search of fixed-output
derivations.

But again, that=E2=80=99s a bit of a sledgehammer, and somewhat inconvenien=
t to
do at the moment.

Ludo=E2=80=99.