[PATCH] Fix unreproducible “guix pack -f docker” (hard link)

[zimoun]

Hi Ludo,

On Sat, 06 Feb 2021 at 22:46, Ludovic Courtès <ludo@gnu.org> wrote:

> Having looked at the tar manual (info "(tar) hard links"), it seems
> clear that this is the default behavior and that we have to pass
> ‘--hard-dereference’ to avoid it.

Attached a patch that fixes the issue, I guess.  Well, I am not sure to
understand all correctly, yet. :-)

Now the 2 images have the same checksum on my 2 machines.

WDYT?


Cheers,
simon

>From 70e113ecccc831d2a111f7c8598157d41fe0de86 Mon Sep 17 00:00:00 2001
From: zimoun <zimon.toutoune@gmail.com>
Date: Mon, 8 Feb 2021 19:37:25 +0100
Subject: [PATCH] guix: docker: Fix undeterministic hard link.

* guix/docker.scm (%tar-determinism-options): Add '--hard-dereference'.
---
 guix/docker.scm | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/guix/docker.scm b/guix/docker.scm
index 97ac6d982b..39e85b7fc2 100644
--- a/guix/docker.scm
+++ b/guix/docker.scm
@@ -2,6 +2,7 @@
 ;;; Copyright © 2017 Ricardo Wurmus <rekado@elephly.net>
 ;;; Copyright © 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2018 Chris Marusich <cmmarusich@gmail.com>
+;;; Copyright © 2021 Simon Tournier <zimon.toutoune@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -112,7 +113,7 @@ Return a version of TAG that follows these rules."
 
 (define %tar-determinism-options
   ;; GNU tar options to produce archives deterministically.
-  '("--sort=name" "--mtime=@1"
+  '("--sort=name" "--mtime=@1" "--hard-dereference"
     "--owner=root:0" "--group=root:0"))
 
 (define directive-file

base-commit: 4cd8bab7d4b345c5538b8d039d84a957df7a235f
-- 
2.29.2