contrib/python-hook-examples.py

treediscovery: always return all remote heads

Old discovery only returned incoming heads, not all of them (for
changegroupsubset). New discovery must always return all of the remote heads
(for getbundle). I failed to properly adjust treediscovery in cb98fed52495
when introducing setdiscovery.

The actual observable problem was 'remote: unsynced changes' when trying
to push a cset on one named branch to a server with a new cset on another
named branch. This scenario is now tested in test-treediscovery.t.

'''
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)))