I really think git made a mistake in conflating the immutable log of what was changed with the (ideally mutable) story of what got merged in. So you see people

I really think git made a mistake in conflating the immutable log of what was changed with the (ideally mutable) story of what got merged in. So you see people arguing over squashing commits vs rebasing vs merging. Squashing commits makes the history of commits a better story of features being added. Merging preserves the immutable log of the actual changes made to the code, and rebasing sort of does a bit of both. But, I don't see any reason we can't have our cake and eat it too. We're programming computers after all and we can make them do whatever we like. If I wrote my own git, I think I'd split commits into those two parts. I'd leave the history of changes immutable - probably with some sort of Merkle DAG like Git does. And then have a separate associated data store which stores the commit messages, in a nice sensible, editable log describing the work that actually happened. Let people arrange and rearrange the commit descriptors however they like. If you want, group commits around feature tags, fix typos and make any changes to the messages that you want. But, the whole while the underlying log of diffs ("what actually changed in the code") can remain (gloriously) unaffected.