Ensuring identical tarballs from releases

Hi all,

I am studying using the ‘releases’ feature of github to distribute the zip/tar files generated, but I need to be sure that these files are always going to match a precomputed hash. In other words, that these files are generated only once and not on demand, which could lead to changes due to git/zip/tar patches (see this SO question).

Now, the URL of release-related tarballs suggest that these are indeed generated only once, when the release is created. On the other hand, tarballs for arbitrary commits (the ones you get from the ‘clone or download’ button) are likely to be generated on demand.

I’ve checked the Releases docs without seeing references to this. Anyone knows for sure, or has any further info? Thanks!

If you need the downloads for a release to be guaranteed unchanging, your best bet is to upload a binary or set of binaries attached to the release. As for arbitrary commits, we can’t guarantee that the tarballs associated with them will be generated once and never change.

I hope that helps!

Thanks for confirming the bit about regular commits. We already had discarded the idea of relying on those.

I understand from your reply that release zips are also at risk of being regenerated at some point?

I didn’t mention in my original post (sorry) but I’m interested in this feature for source distribution only. Uploading binaries, according to the link you posted, seems intended for pre-built binaries, and uploading a zip of sources would be kind of a duplication (although these would certainly be immutable).

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What it sounds like you’re asking for is a 100% guarantee that the release tarballs will not change. That’s something that we aren’t going to guarantee. So if you need to be absolutely certain that a release artifact won’t change, uploading a release artifact is the way to go, whether it’s a duplication in the common case or not.

I hope that helps!


Understood. It was not so much asking for a guarantee as knowing how the process is implemented. Thanks!