jj-gpc

✨ 100% local LLM-based bookmark (Git branch) name creation for Jujutsu VCS

Jujutsu is a modern, Git-compatible VCS. It supports (and I primarily use) anonymous branches for development. Since Git, and thus all Git-based “forges” (GitHub, GitLab, Bitbucket, etc.) require branch names, though, you need to give a branch name when you push your changes for others to work with.

Jujutsu has native support making this easy. If you run jj git push --change <change ID>,it creates a Jujutsu bookmark (which it maps to Git branches) and then pushes that newly created bookmark. The bookmark names it creates are of the form push-<change id>, though. Those are not especially attractive to most collaborators!

This tiny tool is one “solution”: it generates a bookmark name based on the messages associated with the changes you tell it to use—by default, trunk()..@, or “everything between my current working copy and whatever the ‘trunk’ is for this project (usually main or master”).

gpc is short for git push change.

Installation

Prerequisites: a relatively recent version of Rust. (I built it with Rust 1.82, but it probably works with versions quite a bit earlier than that!)

• Clone the repo.

  With Jujutsu:

  jj git clone https://github.com/chriskrycho/jj-gpc

  With Git:

  git clone https://github.com/chriskrycho/jj-gpc.git

• Install it with Cargo:

  cargo install --path . --locked

• Install and run ollama.

• Fetch the phi3 model:

  ollama pull phi3

That’s it; now you can run jj-gpc to do this.

Usage

jj-gpc [change] [flags]

change is the revset to use to generate the bookmark name. If not passed, it will use @.

A few of the most useful flags:

• -f/--from: the initial revision to use in the revset for generating the name. Note that the revset is of the form <from>..<change>, so the <from> message will not be included, because the default is trunk(), and the point is to generate a description of what is different from the trunk.
• -p/--prefix: apply a prefix before the generated bookmark name. For example, jj-gpc -p chriskrycho would produce a name like chriskrycho/did-some-stuff, instead of just did-some-stuff.
• --log-format: pass one-line (the default) to pass just summary messages, or full to pass the whole commit message, to the LLM for branch name description.
• --dry-run: generate a branch name but neither create the bookmark nor push it.

For the full set of flags and more details, run jj-gpc --help!

Example output

A handful of branch names I have actually seen generated by this:

• update-infra-issues
• update-mdbook-dependencies
• software-updates-implemented
• cleaning-and-fixes
• small-bug-fixes
• small-code-updates
• add-some-examples
• small-digital-notebook
• fix-library-errors
• bump-typescript-version
• support-ts-versions