Le mercredi, 23 octobre 2019, 15.49:11 h CET Theodore Y. Ts'o a écrit : > On Wed, Oct 23, 2019 at 11:18:24AM +1000, Russell Stuart wrote: > > On Tue, 2019-10-22 at 16:52 -0700, Russ Allbery wrote: > > > That seems excessively pessimistic. What about Git makes you think > > > it's impossible to create a reproducible source package? > > > > Has it been done? Given this point has been raised several times > > before if it hasn't been done by now I think it's reasonable to assume > > it's difficult, and thinking that it's so is not excessively > > pessimistic. > > Generating a reproducible source package given a particuar git commit > is trivial. All you have to do is use "git archive". For example: When talking about upstream projects, sure. But generating Debian source packages (.dsc and friends) from a `debian/master` (+ `pristine-tar`) reproducibly is not really, right? As far as I understand, `gbp buildpackage -S` is the closest we have, but so far, I fail to get it to give me the bit-by-bit identical unsigned .dsc that I'd like to get. What am I missing? (A little digresssion…) Where I'm coming from is that we were discussing the tag2upload problem at miniDebConf Vaumarcus. The heart of the problem is that FTP-Master are (currently) not going to accept .dscs built reproducibly by a (even trusted) service. tag2upload is built on the idea that a signed git tag is the only needed thing (`git tag -s`) to trigger an upload, and that is not going to fly currently. The solution that seemed obvious during the discussion  is to instead rely on a local tool to produce a git tag with significantly more metadata (such as .dsc signature, _source.changes signature); and reconstruct the a signed set of .dsc and _source.changes automatically (as last pipeline step in Gitlab CI), which are then acceptable by the archive. In other words, its "tag2upload", but with a reproducible way to: - build a source package on developer machine; - sign it locally; - create and push a special git tag Then, in a different environment (such as a GitLab CI pipeline step), given a special git tag and a repository; - build the exact unsigned same source package - unpack the special git tag; - apply the signatures to get the exact same signed source packages; - dput to the archive. The hard part is not the packing and unpacking of the special tag; that's mostly just strings massaging. But building the exact same source package in different environments is harder than I expected. Some caveats: - Q: if you built and signed the source package locally, why not uploading? A: Because you might want to only upload _after_ automated tests, and in an unsupervised manner. - Q: If one can fit pgp signatures in a git tag; why not inlining the complete .dsc and _source.changes? A: Indeed. You still need the debian.tar though. - Q: What about Dgit: in the .dsc, or buildinfo files? A: Currently optional; could just be left out for a prototype. Of course, all of this can only work if we can have, or make the ".git to .dsc" conversion reproducible; hence my query. All-in-all; would this be a welcome mechanism? OdyX  It probably was already considered.
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