contrib/python-hook-examples.py

rust-dirstatemap: cache non normal and other parent set

Performance of `hg update` was significantly worse since the introduction of
the Rust `dirstatemap`. This regression was noticed by Valentin Gatien-Baron
when working on a large repository, as it goes unnoticed for smaller
repositories like Mercurial itself.

This fix introduces the same getter/setter mechanism at `hg-core` level as
for `set/get_dirs`.

While this technique is, as previously discussed, quite suboptimal, it fixes an
important enough problem. Refactoring `hg-core` to use the typestate
pattern could be a good approach to improving code quality in a future patch.

Differential Revision: https://phab.mercurial-scm.org/D8048

'''
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)))