[Buildroot] git tarball hashes [was: Report of Buildroot developer meeting FOSDEM 2019]

[Yann E. MORIN <yann.morin.1998@free.fr>]

Arnout, All,

On 2019-02-08 10:16 +0100, Arnout Vandecappelle spake thusly:
> On 08/02/2019 08:54, Thomas Petazzoni wrote:
> > On Thu, 7 Feb 2019 23:55:24 +0100
> > Arnout Vandecappelle <arnout@mind.be> wrote:
> > 
> >> On 07/02/2019 23:51, Arnout Vandecappelle wrote:
> >>> making sure the git backend
> >>> produces reproducible tarballs by using the pax archive format (Yann started
> >>> working on an implementation for that)  
> >>
> >> ?I realized while writing this: how does this approach fix the instability of
> >> gzip? Or do we assume that that was a one-off?
> > 
> > Which gzip issue are you talking about ? I think we never had a
> > *version* issue with gzip, only with installations where gzip is a
> > symlink to pigz.
> 
>  Ah yes indeed, and someone (Yann?) observed that the output generated by gzip
> has been stable since the dawn of the universe.

Yeah, I tried versions back to 1.2.4, released in 1993, and the output
is strictly identical. To be sure, I just re-did the test right now, and
yeah, it works:

    $ /bin/gzip --version |head -1
    gzip 1.6
    $ /bin/gzip -n -c -9 - <gzip-1.2.4.tar |sha1sum
    889f641f3dd4333065ae94281b1420b965a7f32a  -

    $ ./gzip-1.2.4/gzip --version 2>&1 |head -1
    gzip 1.2.4 (18 Aug 93)
    $ ./gzip-1.2.4/gzip -n -c -9 - <gzip-1.2.4.tar |sha1sum
    889f641f3dd4333065ae94281b1420b965a7f32a  -

So, Woo! for reproducibility! :-)

Regards,
Yann E. MORIN.

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