tests/pullext.py

documentation: add some internals documentation about bid merge

This is an important algorithm that was only documented on the wiki so far.

Some update to the algorithm (and associated doc) is to expected in the future
since the bid merge algorithm is bug-ridden when it comes to file deletion comes
to play.

Differential Revision: https://phab.mercurial-scm.org/D8711

# pullext.py - Simple extension to test pulling
#
# Copyright 2018 Gregory Szorc <[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

from mercurial.i18n import _
from mercurial import (
    commands,
    error,
    extensions,
    localrepo,
)
from mercurial.interfaces import repository


def clonecommand(orig, ui, repo, *args, **kwargs):
    if kwargs.get('include') or kwargs.get('exclude'):
        kwargs['narrow'] = True

    if kwargs.get('depth'):
        try:
            kwargs['depth'] = int(kwargs['depth'])
        except ValueError:
            raise error.Abort(_('--depth must be an integer'))

    return orig(ui, repo, *args, **kwargs)


def featuresetup(ui, features):
    features.add(repository.NARROW_REQUIREMENT)


def extsetup(ui):
    entry = extensions.wrapcommand(commands.table, b'clone', clonecommand)

    hasinclude = any(x[1] == b'include' for x in entry[1])
    hasdepth = any(x[1] == b'depth' for x in entry[1])

    if not hasinclude:
        entry[1].append(
            (b'', b'include', [], _(b'pattern of file/directory to clone'))
        )
        entry[1].append(
            (b'', b'exclude', [], _(b'pattern of file/directory to not clone'))
        )

    if not hasdepth:
        entry[1].append(
            (b'', b'depth', b'', _(b'ancestry depth of changesets to fetch'))
        )

    localrepo.featuresetupfuncs.add(featuresetup)