reproducible builds and python

[Nick Coghlan]

On 08/12/2014 04:01 AM, bmorbach wrote:
> Hi everyone!
> 
> I've been doing some work towards reproducible builds in Fedora (mostly
> with various upstreams so far) and one of the elephants in the Room are
> obviously Pythons .pyc and .pyo files.
> 
> As those contain the mtime of the original .py file, they might be
> different for each rebuild of an srpm.
> For many rpms this isn't a problem, because the files are not modified
> and thus retain their timestamp from the archive. Quite a few rpms do
> modify to .py files though and because of that, every build has a
> different result.
> 
> I would like to propose to set the mtime of all .py files to a fixed
> (for this specific srpm) time. This could be done
> in /usr/lib/rpm/brp-python-bytecompile before doing the actual
> byte-compilation. This would result in the same .py{c,o} files being
> created for each rebuild.

This sounds like a reasonable approach to me, especially if the mtime
for the SRPM is derived from dist-git.

Regards,
Nick.

-- 
Nick Coghlan
Red Hat Hosted & Shared Services
Software Engineering & Development, Brisbane

HSS Provisioning Architect