jj: Git/Monorepo Compatible Version Control

Recently a few newer projects have come to my attention surrounding version control tools. I have been a little bit curious and somewhat skeptical about trying them out.

Just to get potential bias out of the way - I do work at Google (currently as Hardware Operations - with a sprinkle of software development / software engineering), so if that sways my opinions down below, I would rather say it here before going further.

Sapling

Sapling is version control that is “git compatible” coming from Meta (Facebook) open source. I have to imagine I might be more compelled to look into this project if I worked at Meta and had to work with their monorepo instead of Google’s.

Jujutsu (jj)

Jujutsu is a side project that comes from Googler Martin von Zweigbergk and I have heard of mostly from other Googlers, not as much from the open source community.

The main appeal seems to be some nice quality-of-life features that it layers on top of existing version control systems (like git and Mercurial/Piper and for the monorepo at Google).

The Experiment

Naturally I wanted to give it a try to see how it stacks up to git. Admittedly I am not much of a git power user, but I am familiar and comfortable with basic operations on my repos like branching, merging and of course committing code. I mostly use git from the CLI as well.

I want to see if Jujutsu has anything to offer for a basic/intermediate git user such as myself (I occasionally push code to the monorepo at work as well).

I will be trying it out and report back my thoughts and findings - either amending this post or in a new one.

Until next time!

Update 06-16-26 (a few weeks later)

jj is good and I think improves on many things from git. In particular, I think the configuration/CLI ergonomics work better than git for me personally. Having subcommands like jj fix and jj config edit --user are really good and it just makes sense in my mind. Having a configurable default command makes sense.

The thing that I struggle with is the concept of revset and the mini language used to represent them revest docs.

I know the basics, however I am still having to resort to the docs to find out how to do things that I know how to do in Git. There is a helpful command table to help with that as well.

Happy hacking!