From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ricardo Wurmus <rekado@elephly.net>
Subject: Re: [PATCH] Help Ruby packages be reproducible
Date: Wed, 30 Dec 2015 09:26:20 +0100
Message-ID: <877fjwbavn.fsf@elephly.net>
References: <56821E47.9010400@uq.edu.au> <87io3h4ta3.fsf@elephly.net>
	<56832AA3.8030109@uq.edu.au> <56832BA6.6030806@uq.edu.au>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Return-path: <guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org>
Received: from eggs.gnu.org ([2001:4830:134:3::10]:33785)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <rekado@elephly.net>) id 1aEC5Z-0000kK-TO
	for guix-devel@gnu.org; Wed, 30 Dec 2015 03:26:34 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <rekado@elephly.net>) id 1aEC5W-0000zu-MX
	for guix-devel@gnu.org; Wed, 30 Dec 2015 03:26:33 -0500
Received: from sender163-mail.zoho.com ([74.201.84.163]:25868)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <rekado@elephly.net>) id 1aEC5W-0000zI-El
	for guix-devel@gnu.org; Wed, 30 Dec 2015 03:26:30 -0500
In-reply-to: <56832BA6.6030806@uq.edu.au>
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: Ben Woodcroft <b.woodcroft@uq.edu.au>
Cc: "guix-devel@gnu.org" <guix-devel@gnu.org>


Ben Woodcroft <b.woodcroft@uq.edu.au> writes:

> From 3d23171d88b9f38c90efa469f6519b52b15a1d01 Mon Sep 17 00:00:00 2001
> From: Ben Woodcroft <donttrustben@gmail.com>
> Date: Wed, 30 Dec 2015 10:27:33 +1000
> Subject: [PATCH] build: ruby: Remove cached gem after install.

> The .gem file stored in GEM_HOME after install is both redundant and an
> archive that stores timestamped files which makes builds non-deterministic. So
> delete it after 'gem install'.

Good idea!  I don’t know if the existence of the cached gem is checked
for by any Ruby tools (bundler or the like).  Is there some
documentation about this cache?

> -    (zero? (apply system* "gem" "install" (first-matching-file "\\.gem$")
> -                  "--local" "--ignore-dependencies"
> -                  ;; Executables should go into /bin, not /lib/ruby/gems.
> -                  "--bindir" (string-append out "/bin")
> -                  gem-flags))))
> +    (apply system* "gem" "install" gem-name
> +           "--local" "--ignore-dependencies"
> +           ;; Executables should go into /bin, not /lib/ruby/gems.
> +           "--bindir" (string-append out "/bin")
> +           gem-flags)
> +    ;; Remove the cached gem file as this is unnecessary and contains
> +    ;; timestamped files rendering builds not reproducible.
> +    (delete-file (string-append gem-home "/cache/" gem-name))
> +    #t))

I’d prefer to keep ‘(zero? ...)’ and only delete the file when the
‘system*’ call above succeeded.  It would be nice if we could propagate
any bad return value from ‘system*’ to the end of the procedure.

Maybe something like this:

  (and (zero? (apply system* ...))
       (begin (delete-file ...) #t))

It’s a bit clunky but the return value would still be #f if ‘system*’
fails.  What do you think?

~~ Ricardo