jj-pre-push

A very limited integration between jj and pre-commit allowing you to run your pre-push hooks in a colocated jj/git repository.

I don't expect this to last forever, it's just a stopgap until some jj-native mechanism arrives that can take over.

Prior art:

• https://www.aazuspan.dev/blog/automating-pre-push-checks-with-jujutsu/
• Various comments on https://github.com/jj-vcs/jj/issues/405

Usage

Use jj-pre-push push (or an alias - personally I use jj push) as a replacement for jj git push. It takes all the same arguments, and does the following:

1. Determines which bookmarks the corresponding jj git push will update on the remote, and how they would change.

2. For each of these bookmarks in turn:

   • Checks out the bookmark to the working copy (or uses the existing working commit if it is empty and based on the bookmark).
   • Runs the pre-push hooks defined in your .pre-commit-config.yaml on the same set of files pre-commit would when pushing the same change. (For existing branches that's the files touched in the range old...new; for new branches it's the files touched in all ancestors of new that aren't present on the remote.)
   • Reports any failures; and if any files were modified reports the change ID(s) in which these modifications can be found.

   Note: If your current working commit is empty and is a direct child of the bookmark being checked, jj-pre-push will run the checks directly in that working commit instead of creating a new one. Any modifications made by the hooks will be preserved in your working commit, ready to be diffed or squashed.

3. If all hooks succeeded on all branches, executes jj git push with the arguments provided; otherwise nothing is pushed.

4. Returns the working copy to its original change.

If there is no .pre-commit-config.yaml in your workspace root, jj-pre-push push immediately delegates to jj git push.

By default jj-pre-push produces no console output of its own unless hooks fail. If you'd like to see more details about what's happening, you can use jj-pre-push --log-level=INFO push.

Installation

If you have uv installed and you're planning to use an alias anyway, you can avoid explicitly installing at all with uvx, e.g. with this jj configuration for jj push:

[aliases]
push = ["util", "exec", "--", "uvx", "jj-pre-push", "push"]

Otherwise, install the PyPI package jj-pre-push in whichever way you prefer; e.g. uv tool install jj-pre-push or pip install jj-pre-push, and use jj-pre-push push as described earlier.

Usage with jjui

If you're a jjui fan (I think maybe you should be!), here's an example jjui/config.toml snippet showing how you can define custom actions to invoke jj-pre-push: one to perform the default jj push, and one to push the bookmarks attached to the change you have currently selected in the UI. I've also added some examples of key sequence bindings to perform these actions.

[[actions]]
name = "jj-push"
lua = '''
  jj_async("push")
  revisions.refresh()
'''

[[actions]]
name = "jj-push-selected"
lua = '''
  jj_async("push", "-r", context.commit_id())
  revisions.refresh()
'''

[[bindings]]
action = "jj-push"
seq = ["x", "p"]
scope = "revisions"
desc = "jj push"

[[bindings]]
action = "jj-push-selected"
seq = ["x", "P"]
scope = "revisions"
desc = "jj push selected bookmark(s)"

Note that these depend upon the jj push alias defined in the previous section.

Usage with other checkers/hook managers

jj-pre-push has rudimentary support for checkers other than pre-commit - to use a different checker, specify its name on the command line with jj-pre-push --checker CHECKER ... or set the environment variable JJ_PRE_PUSH_CHECKER. Supported checkers:

• pre-commit
• prek, or any other checker with a pre-commit-compatible CLI
• hk