[npikall]

I’m a big fan of @caarlos0’s tools; he usually has already built whatever I’m looking for. I use jj-vcs as my primary VCS, and svu currently only supports git repos. Since jj is git-compatible, supporting it seemed like a natural fit.

Disclosure: most of this code was AI-generated. I’ve reviewed and tested it as described below, but I’m happy to rework anything. If you’d rather review it in smaller pieces, I can split the PR.

Every commit in this PR builds and passes the test suite on its own (go build && go test ./... && golangci-lint run), so it can be reviewed and bisected commit by commit.

What it does

• Detects the nearest .git /.jj marker.
• Colocated repos keep using the existing git code path, so nothing changes for them.
• Non-colocated jj repos read tags and history through the jj CLI.
• Git logic moves behind a backend interface in internal/vcs, and tag/log parsing is shared between backends.

Testing

• Unit Tests added
• Manually tested on a colocated repo and a non-colocated repo

Happy to hear whether this is something you’d want in svu at all, even before a detailed review.