contrib/python-hook-examples.py

formating: upgrade to black 20.8b1

This required a couple of small tweaks to un-confuse black, but now it
works. Big formatting changes come from:

 * Dramatically improved collection-splitting logic upstream
 * Black having a strong (correct IMO) opinion that """ is better than '''

Differential Revision: https://phab.mercurial-scm.org/D9430

'''
Examples of useful python hooks for Mercurial.
'''
from __future__ import absolute_import
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)))