[philh]

I'd be somewhat surprised if the bzr->git conversion did in fact mess those up. I was following ESR's blog when he was doing the conversion. He seemed to feel very strongly that the conversion should not mess things up like that. (His goal was that the history should look like it would have done, if people had always been using git.)

On the other hand, I'm less confident about the conversion to bzr. And anyway the relevant question is not "would it have broken?" but "did people have reason to expect it would break?"

And on the third hand, a commit id could be referenced by author and timestamp, which would be invariant under (competent) repo conversions.

[LukeShu]

The bzr->git conversion does look like it was always in git from a looking-at-the-repo viewpoint (sans commit messages mentioning RCS/CVS, et c.); but in-repo data wasn't changed much; when building from VCS, it sticks a VCS identifier in the version; prior to a certain commit the script for that tries to grab the commit ID from bzr instead of git. However, ESR's blog does suggest that commit hashes mentioned in the source were replaced; I'm not sure if that's true.

That said, referencing the commit by author and timestamp, instead of internal commit ID is the robust solution.