mercurial/debugcommands.py

debugcommands: introduce standalone module for debug commands

commands.py is our largest .py file by nearly 2x. Debug commands live
in a world of their own. So let's extract them to their own module.

We start with "debugancestor."

We currently reuse the commands table with commands.py and have a hack
in dispatch.py for loading debugcommands.py. In the future, we could
potentially use a separate commands table and avoid the import of
debugcommands.py.

# debugcommands.py - command processing for debug* commands
#
# Copyright 2005-2016 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import os

from .i18n import _
from . import (
    cmdutil,
    commands,
    error,
    revlog,
    scmutil,
)

# We reuse the command table from commands because it is easier than
# teaching dispatch about multiple tables.
command = cmdutil.command(commands.table)

@command('debugancestor', [], _('[INDEX] REV1 REV2'), optionalrepo=True)
def debugancestor(ui, repo, *args):
    """find the ancestor revision of two revisions in a given index"""
    if len(args) == 3:
        index, rev1, rev2 = args
        r = revlog.revlog(scmutil.opener(os.getcwd(), audit=False), index)
        lookup = r.lookup
    elif len(args) == 2:
        if not repo:
            raise error.Abort(_('there is no Mercurial repository here '
                                '(.hg not found)'))
        rev1, rev2 = args
        r = repo.changelog
        lookup = repo.lookup
    else:
        raise error.Abort(_('either two or three arguments required'))
    a = r.ancestor(lookup(rev1), lookup(rev2))
    ui.write('%d:%s\n' % (r.rev(a), hex(a)))