Detect a closed branch in Mercurial

Question

I'm trying to write a post-commit hook in my Puppet repository that works like this git-based setup. I have some of the basics ready, such as detecting when a new branch is created and changing to the proper directory to do a clone (or pull if it exists) with the right branch name, but I want to add a bit that cleans up when a branch is closed. Thus, I'm trying to find out how to detect via a changeset that a branch is closed, other than relying on the commit message. Maybe I'm missing it, but I don't see anything obvious that says "this commit was to close this branch" - I could perhaps try to detect an empty changeset, but that seems like it might have false positives.

Answer 1

Here's an example of a hook which detects a closed branch:

from mercurial import context, ui
def run(ui, repo, node, **kwargs):
    ctx = repo[node]
    for rev in xrange(ctx.rev(), len(repo)):
        ctx = context.changectx(repo, rev)
        parent1 = ctx.parents()[0]
        if parent1 != None and parent1.extra().get('close'):
            ui.warn("Commit to closed branch!\n")
            return True
    return False

The hook can run in pretxnchangegroup mode (checked when changesets added from external repo) with the following hgrc

[hooks]
pretxnchangegroup.closed_branch = python:/path/to/closed_branch.py:run