More on Differential Reproducible Builds: Devuan is 46% reproducible!

Building on my work to rebuild Trisquel GNU/Linux 11.0 aramo, it felt simple to generalize the tooling to any two apt-repository pairs and I’ve created debdistreproduce as a template-project for doing this through the infrastructure of GitLab CI/CD and meanwhile even set up my own gitlab-runner on spare hardware. I’ve brought over reproduce/trisquel to using debdistreproduce as well, and archived the old reproduce-trisquel project.

After fixing some quirks, building Devuan GNU+Linux 4.0 Chimaera was fairly quick since they do not modify that many packages, and I’m now able to reproduce 46% of the packages that Devuan Chimaera add/modify on amd64. I have more work in progress here (hint: reproduce/pureos), but PureOS is considerably larger than both Trisquel and Devuan together. I’m not sure how interested Devuan or PureOS are in reproducible builds though.

Reflecting on this work made me realize that while the natural thing to do here was to differentiate two different apt-based distributions, I have realized the same way I did for debdistdiff that it would also be interesting to compare, say, Debian bookworm from Debian unstable, especially now that they should be fairly close together. My tooling should support that too. However, to really provide any benefit from the more complete existing reproducible testing of Debian, some further benefit from doing that would be useful and I can’t articulate one right now.

One ultimate goal with my effort is to improve trust in apt-repositories, and combining transparency-style protection a’la apt-sigstore with third-party validated reproducible builds may indeed be one such use-case that would benefit the wider community of apt-repositories. Imagine having your system not install any package unless it can verify it against a third-party reproducible build organization that commits their results in a tamper-proof transparency ledger. But I’m now on repeat here, so will stop.