contrib/python-hook-examples.py

hghave: document format for version feature checks as <name><vers>, no dots

I had a bit of a difficult time when attempting to fix a use of `py-38` when
trying to figure out what the correct way of specifying the feature was. By
having the strings 'py-3*' and 'py3.8' in the hghave.checkvers docstring, I
would have had a much easier time of it instead of having to trace exactly what
was happening here.

Differential Revision: https://phab.mercurial-scm.org/D7023

'''
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)))