contrib/python-hook-examples.py

visibility: improve the message when accessing filtered obsolete rev

When trying to access filtered revision, it is likely because they have been
obsoleted by an obs-marker. The current message shows how to access the
revision anyway:

    abort: hidden revision '13bedc178fce'!

But in the case of an obsoleted revision, the user is likely to want to update
to or use the successor of the revision.

We update the message to display more information about the obsolescence fate
of the revision in the following cases:

    abort: hidden revision '13bedc178fce' is pruned!

    abort: hidden revision '13bedc178fce' has diverged!

    abort: hidden revision '13bedc178fce' was rewritten as X, Y and 2 more!

Differential Revision: https://phab.mercurial-scm.org/D1591

'''
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)))