Jujutsu: a new, Git-compatible version control system

Yes, there are various tools to move changes between commits and chop them up, including `jj move`, `jj amend`/`jj unamend`, and `jj split`, and they're quite easy and simple to use. For example, you can `jj move --from xyz --to abc README.md` to only move the changes in the file README from change xyz, to abc. `amend` and `unamend` are basically specializations of `move`, for the current working-copy-commit and the parent change. I use these probably dozens or hundreds of times a day, actually. They also can all be invoked in --interactive mode so you get a terminal TUI to select individual hunks or lines out of files, for a more granular experience. (And that TUI comes built-in; you don't need to install third party tools for it to work out of the box.)

The idea isn't really that the index is useless; quite the contrary. I chop commits up with far more power than I did before. Rather, it's just that you can represent these multiple concepts with a single design primitive. So, the index and the stash and those 'wip' commits we all put onto a quick temporary branch -- they're all the same thing now. They use the same vocabulary, the same verbs and nouns in the user interface, et cetera.

If you live in Emacs/Magit though, I suspect prying yourself away from it will be hard, even despite that. :)

Disclosure: I am a contributor to Jujutsu (not Google or otherwise work affiliated.)