If you're going to check it in, at least have a CI job which rebuilds it from scratch, then fails if there are any changes. I'm not persuaded of the value of h

If you're going to check it in, at least have a CI job which rebuilds it from scratch, then fails if there are any changes. I'm not persuaded of the value of having diffs in source control, but i haven't looked at concrete examples. This would be an interesting post for someone to write. For performance, i'd rather follow a distributed caching approach. Hash the true source, look for /some/nfs/mount/or/s3/path/${hash}.tar.gz, if it exists, unpack it into the generated source directory, if not, generate the source, tarball it, and upload that to the said path. Takes some care to hash the right things (needs to include the version and configuration of the generation tool, etc). Again, you could have a CI job checking that the caches are correct if you're worried.