contrib/python-hook-examples.py

revset: don't cache abstractsmartset min/max invocations infinitely

There was a "leak", apparently introduced in ab66c1dee405. When running:

    hg = hglib.open('repo')
    while True:
        hg.log("max(branch('default'))")

all filteredset instances from branch() would be cached indefinitely by the
@util.cachefunc annotation on the max() implementation.

util.cachefunc seems dangerous as method decorator and is barely used elsewhere
in the code base. Instead, just open code caching by having the min/max
methods replace themselves with a plain lambda returning the result.

'''
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['tip'].node()
    else:
        last = node
    diff = patch.diff(repo, first, last)
    ui.write(patch.diffstat(util.iterlines(diff)))