contrib/python-hook-examples.py

transaction: always remove empty journal on abort

When transactions without entries were aborted, the journal (of size 0) was not
unlinked, which prevents subsequent operations until hg recover is run on the
repository.

We also make sure the journal is unlinked when committing, even if the provided
hook doesn't do so.

'''
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].parents()[0].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)))