Maybe I’m weird that way. I’ve had too many coworkers who don’t really even look at annotations to remind themselves why this code was written in the first place. They will just yolo and hope nobody ties the problems back to them. But once you’ve dealt with an irate customer who waited impatiently for a bug to be fixed, and only to have the bug be reintroduced a short time later, you may become more circumspect about bug fixes.
There’s often a refactor needed to fix multiple bugs at once. There’s often refactor can open up new feature opportunities, or performance improvements.
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.
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.
Yes, you're supposed to avoid moving later commits across a rebase... but the reason you're supposed to avoid that is because git is so bad at it.
Where I agree with your take partially is that the UX for all of this in git is not great, and that ends up meaning that most people don't actually use git in this way. If the process of manually structuring the commits to clean up history on a feature branch were more intuitive, then I'd predict the issues of history-destroying rebases to essentially be moot; everyone would just present the commits for review exactly as we'd want them before review, and then we'd fast-forward merge into the main development branch without any issue. The problem is that doing this sort of restructuring after the fact isn't actually easy to learn how to do because of the poor ergonomics of the git CLI, so it's both tedious and error-prone for almost everyone. My perspective is that most of the concern around messing with history in git comes from being burnt by changes that were not intended by the one making them, and that workflows that avoid it (like merge commits) are essentially a compromise to avoid that risk by accepting a certain amount of cruft in the history of the main development branch. I don't blame anyone for using them, since the problems that make the rebase workflow harder are very real, but I don't think that the fact that rebase changes history is the real issue as much as it provides a mechanism for the actual underlying issues to manifest.
Git is a decentralized version control system. It is effectively a blockchain like Bitcoin but without the consensus mechanism, and just like transactions are final on the Bitcoin network, pushed commits are final in git. You can agree to use one branch over another, but if you are using git as designed (i.e. as a decentralized system), it can be confusing. Merge commits are how you can resolve that confusion.
Like if I have branch X and branch Y, and X is 1 commit ahead of Y, but I alter the comment of a commit in Y, now X is one or more commits behind Y and will not recognize identical code-changes as identical.
It gets worse if you squash a commit, where you start getting conflicts during merges and rebases even though the code-changes are the same.
I understand why these problems happen, and the ways to prevent it (don't rebase anything pushed), but it still underscores the fact that git doesn't properly accommodate its own love of rewriting history.
If git had a proper synced graph of history-rewriting actions (commit A was rewritten into commit B) then it would be able to provide better responses when doing a merge or reflist across rewritten branches.
Commits are actually snapshots of the entire repository, not just diffs, so even if the diff is the same, if the base is different, it is not the same commit. And when you rebase, all the old commits will stay there until you run the garbage collector, and only if they don't have a head.
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".
There’s also a fun loophole where you can edit other people’s commits when doing a merge and attribute bugs to someone else. I caught someone doing this once (they were terrible at git) on account of I was the one who reviewed the code that got changed, and I specifically looked for that class of bug before approving it. Git blame and the commit history no longer agreed and I was able to show what happened.
Most of the rest of us do not work this way, but they still do. The rest of us also only have to deal with three way merges most of the time, instead of octopus merges. Though I jokingly call, “fixing an incorrect three way merge” a “five way merge” because you end up doing a star shaped pattern of diffs to re-resolve the code to retain the intents of all three versions. A to merge, B to merge, merge to HEAD~, A to HEAD~ and B to HEAD~
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.