Re: Unreproducible «When Docker images become fixed-point»?

[zimoun]

Hi,

On Mon, 04 Jul 2022 at 15:37, Ludovic Courtès <ludovic.courtes@inria.fr> wrote:

> Do you still have the original tarball mentioned in the post?

Sadly no.


> A possible reason why we’re building a different derivation than back
> then is provenance info: as explained under ‘--save-provenance’ in the
> manual, provenance info is not “canonical” and we could end up including
> different provenance info.  I don’t have any clear scenario in mind but
> that sounds plausible.

I do not understand why provenance is not deterministic.  I mean I
understand that two provenances can build the same pack, but I miss why

        guix time-machine -C channels.scm \
             -- pack -f docker --save-provenance -m manifest.scm

is not building the same pack for the exact same channels.scm and
manifest.scm files.  Why the resulting provenance info should be
different?

Maybe I overlook a point.  From my understanding, in this case of “guix
machine -C channels.scm”, the provenance is only determined by the file
channels.scm and the provenance thus is unique.

Maybe there is bug in how the provenance is managed; but I do not think
it comes from this part.  Instead, I vaguely think the bug is from
elsewhere – dependent on filesystem or unsorted list or other creative
ideas. :-)

Sadly, we are lacking information for more investigations.  For
instance, it would have been useful to have the checksum of the pack and
so compare.  Or be able to compare the derivations.

Well, let save some data, replay this scenario 6 months later and
investigate. :-)  Keep you in touch.


Cheers,
simon