It's unfortunate that change IDs aren't considered. There was a discussion [1]
in 2025, and it has resurfaced a couple of times since.
Basically, the idea is to attribute a new kind of ID to an initial 'change'. During review, or whenever a commit is rebased, the change ID is kept, whereas the commit of course changes. This allows tooling to identify all previous versions of a change, and is what enables "per-commit" code review à la Gerrit [2] (which IMO is a much better experience than the branch-review-squash model that GitHub normalized). It's also used in jj, although I'm not familiar with that.
As of today, any tool that wants a change ID needs to somehow encode it in commit message bodies. The proposed discussion was about making a change ID a standard header field that git would natively keep across rebases.
They aren't really. It's basically like getting an auto generated ref/branch name for each new commit, with convenience rewriting every ref when you rebase.
It's a bit more convenient if you prefer referring to a non-leaf commit directly rather than relative to the leaf branch a la master~2
jodersky · · focus · HN ↗
Basically, the idea is to attribute a new kind of ID to an initial 'change'. During review, or whenever a commit is rebased, the change ID is kept, whereas the commit of course changes. This allows tooling to identify all previous versions of a change, and is what enables "per-commit" code review à la Gerrit [2] (which IMO is a much better experience than the branch-review-squash model that GitHub normalized). It's also used in jj, although I'm not familiar with that.
As of today, any tool that wants a change ID needs to somehow encode it in commit message bodies. The proposed discussion was about making a change ID a standard header field that git would natively keep across rebases.
[1] <a href="https://lore.kernel.org/git/Z_OGMb-1oV0Ex05e@pks.im/T/#mf941e62af35984f95db8582dbffd7f4d865daf07" rel="nofollow">https://lore.kernel.org/git/Z_OGMb-1oV0Ex05e@pks.im/T/#mf941...
[2] <a href="https://gerrit-review.googlesource.com/Documentation/user-changeid.html" rel="nofollow">https://gerrit-review.googlesource.com/Documentation/user-ch...
lostmsu · · focus · HN ↗
Ferret7446 · · focus · HN ↗
It's a bit more convenient if you prefer referring to a non-leaf commit directly rather than relative to the leaf branch a la master~2