Git Notes: Git's coolest, most unloved­ feature (2022)

Git notes are only cool if you frequently add text to a commit after the commit has happened and visible to others.

The Acked-By and mailing list discussion link examples don't seem to be good examples. Both of these are likely already known when the commit is made. And git commit message basically can have an unlimited length, so you could very well copy all the discussions about the commit that happened on a forge into the commit message itself.

One use case I think might be a better example is to add a git note to a commit that has later been reverted.

> The Acked-By and mailing list discussion link examples don't seem to be good examples. Both of these are likely already known when the commit is made.

Discussion regarding a commit (is: review) and acknowledgment of a commit cannot happen before the commit has been made.

> One use case I think might be a better example is to add a git note to a commit that has later been reverted.

Commit messages are better for this use case. When you got blame a file, it shows the latest changes for that file. If a commit reverts changes from another commit, the newer commit that reverts the older commit will show up in the blame.

> Discussion regarding a commit (is: review) and acknowledgment of a commit cannot happen before the commit has been made.

It can't happen before the commit on a feature branch, but it can happen before merging the commit back to the main development branch. Given that a rebase or merge commit is already frequently necessary to integrate changes from a feature branch after review is finished, I don't see why this type of info couldn't be added (or even required to exist) before merging.

The history-destroying problems of rebasing are a rant on their own.

Can you say more? I use rebase to avoid history destruction/obscuration. Do you mean squash? If so then I agree.

Basically, the fact that any kind of tweaking to the history in terms of comments or grouping together related commits into a single commit changes the hashes. This means that git's normally useful ability to check "hey is commit X in the history of both branches A and B" is broken.

That's a huge usability problem with git. Even as simple as a "rebase on merge" or "squash on merge" automation makes it impractical to push your topic-branch and keep working locally on that same branch while your topic-branch is being reviewed and tested, because git doesn't retain any concept of the fact that "this block of commits has been transformed into that block of commits and so you can consider them one-and-the-same".

I'm the git sme at my office and I deeply resent the amount of time I have to spent training juniors and students around git's jagged edges.

Ideally git should have a proper in-repo objects that reify a relationship between rebased/squashed/amended/etc commits and their predecessors and exposes that when you ask things like "hey is commit X in ref Y?" it could say "no, but there is a modified version of that commit".