Re: Unreproducible “guix pack -f docker” because config.scm-builder

[Ludovic Courtès]

Hi,

zimoun <zimon.toutoune@gmail.com> skribis:

> First on Debian and second on Ubuntu
>
> $ stat 
> /gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/libexec/getconf/POSIX_V6_LP64_OFF64
>   File: 
> /gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/libexec/getconf/POSIX_V6_LP64_OFF64
>   Size: 29960           Blocks: 64         IO Block: 4096   regular file
> Device: 801h/2049d      Inode: 8129616     Links: 5
> Access: (0555/-r-xr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
> Access: 2021-02-05 17:37:15.728728952 +0100
> Modify: 1970-01-01 01:00:01.000000000 +0100
> Change: 2020-06-17 12:40:06.389935679 +0200
> Birth: -
>
> $ stat 
> /gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/libexec/getconf/POSIX_V6_LP64_OFF64
> Fichier : 
> /gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/libexec/getconf/POSIX_V6_LP64_OFF64
> Taille : 29960       Blocs : 64         Blocs d'E/S : 4096   fichier
> Périphérique : 814h/2068d       Inœud : 148900093   Liens : 1
> Accès : (0555/-r-xr-xr-x)  UID : (    0/    root)   GID : (    0/ root)
> Accès : 2021-02-05 17:46:05.537903382 +0100
> Modif. : 1970-01-01 01:00:01.000000000 +0100
> Changt : 2020-12-04 23:16:33.155711694 +0100
> Créé : -

See?  One has just 1 link (did you disable deduplication on that one?),
there other has 5 links.

>> I wonder if it could be that tar nowadays decides to preserve hard links
>> by default and one of your machine had this file hard-linked while the
>> other one didn’t.
>
> Wow, I thought that the same tar was used the one provided by Guix and
> not by the host.  For sure the default tar are not the same on both
> machine (v1.30 for Debian and v1.29 for Ubuntu).
>
> What is the md5sum checksum of ’guix pack -f docker hello’ on Guix
> System for commit b9a54aa?

--8<---------------cut here---------------start------------->8---
$ md5sum $(guix time-machine --commit=b9a54aa -- pack -f docker hello)
b5fe393d7966cbc3cd0be6e51d3aedc3  
/gnu/store/nkvlqwzvxdlhzlc7vhfcngxc19x2ay2f-docker-pack.tar.gz
$ sha1sum $(guix time-machine --commit=b9a54aa -- pack -f docker hello)
a4dff93de6c0bc65eb325ebfeea398ebea944a85  
/gnu/store/nkvlqwzvxdlhzlc7vhfcngxc19x2ay2f-docker-pack.tar.gz
$ guix time-machine --commit=b9a54aa -- pack -f docker hello -d
/gnu/store/323k33sfx869d0nkh69ary8sj6xiy4s4-docker-pack.tar.gz.drv
$ (mkdir /tmp/docker; tar xf $(guix time-machine --commit=b9a54aa -- pack -f 
docker hello ); tar tvf */layer.tar | grep ^h | head)
hr-xr-xr-x root/root         0 1970-01-01 01:00 
gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/libexec/getconf/POSIX_V6_LP64_OFF64
 kunligo al gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/bin/getconf
hr-xr-xr-x root/root         0 1970-01-01 01:00 
gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/libexec/getconf/POSIX_V7_LP64_OFF64
 kunligo al gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/bin/getconf
hr-xr-xr-x root/root         0 1970-01-01 01:00 
gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/libexec/getconf/XBS5_LP64_OFF64
 kunligo al gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/bin/getconf
hr--r--r-- root/root         0 1970-01-01 01:00 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/crtendS.o
 kunligo al 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/crtend.o
hr--r--r-- root/root         0 1970-01-01 01:00 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/install-tools/gsyslimits.h
 kunligo al 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/include-fixed/syslimits.h
hr--r--r-- root/root         0 1970-01-01 01:00 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/install-tools/include/README
 kunligo al 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/include-fixed/README
hr--r--r-- root/root         0 1970-01-01 01:00 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/install-tools/include/limits.h
 kunligo al 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/include-fixed/limits.h
hr--r--r-- root/root         0 1970-01-01 01:00 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/plugin/include/gsyslimits.h
 kunligo al 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/include-fixed/syslimits.h
hrwxrwxrwx root/root         0 1970-01-01 01:00 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/plugin/libcc1plugin.so.0
 kunligo al 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/plugin/libcc1plugin.so
hrwxrwxrwx root/root         0 1970-01-01 01:00 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/plugin/libcp1plugin.so.0
 kunligo al 
gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/plugin/libcp1plugin.so
--8<---------------cut here---------------end--------------->8---

Most of these ‘h’ lines for hard links; ‘libcc1plugin.so’ seems to be an
exception (it’s a symlink).

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.

Thanks,
Ludo’.