view contrib/python-hook-examples.py @ 50244:07d030b38097 stable

rust-dirstate-v2: don't write dirstate if data file has changed

This fixes the following race:
    - process A reads the dirstate
    - process B reads and writes the dirstate
    - process A writes the dirstate

This either resulted in losing what process B had just written or a crash
because the `uuid` had changed and we were trying to write to a file that
doesn't exist. More explanations inside.

This doesn't fix the issue for dirstate-v1, a later patch addresses it.

'''
Examples of useful python hooks for Mercurial.
'''
from mercurial import (
    patch,
    util,
)


def diffstat(ui, repo, **kwargs):
    """Example usage:

    [hooks]
    commit.diffstat = python:/path/to/this/file.py:diffstat
    changegroup.diffstat = python:/path/to/this/file.py:diffstat
    """
    if kwargs.get('parent2'):
        return
    node = kwargs['node']
    first = repo[node].p1().node()
    if 'url' in kwargs:
        last = repo.changelog.tip()
    else:
        last = node
    diff = patch.diff(repo, first, last)
    ui.write(patch.diffstat(util.iterlines(diff)))