contrib/python-hook-examples.py

mergestate: add a constructor that sets up a clean merge state

Eventually, we'll move the read call out of the constructor. This will:
- avoid unnecessary reads when we're going to nuke the merge state anyway
- avoid raising an exception if there's an unsupported merge record

'clean' seems like a good name for it because I wanted to avoid anything with
the word 'new' in it, and 'reset' is more an action performed on a merge state
than a way to get a new merge state.

Thanks to Martin von Zweigbergk for feedback about naming this.

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