view hgext/narrow/__init__.py @ 49010:681b25ea579e

contrib: add a partial-merge tool for sorted lists (such as Python imports)

This is a pretty naive tool that uses a regular expression for
matching lines. It is based on a Google-internal tool that worked in a
similar way.

For now, the regular expression is hard-coded to attempt to match
single-line Python imports. The only commit I've found in the hg core
repo where the tool helped was commit 9cd6292abfdf. I think that's
because we often use multiple imports per import statement. I think
this tool is still a decent first step (especially once the regex is
made configurable in the next patch). The merging should ideally use a
proper Python parser and do the merge at the AST (or CST?) level, but
that's significantly harder, especially if you want to preserve
comments and whitespace. It's also less generic.

Differential Revision: https://phab.mercurial-scm.org/D12380

# __init__.py - narrowhg extension
#
# Copyright 2017 Google, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''create clones which fetch history data for subset of files (EXPERIMENTAL)'''


from mercurial import (
    localrepo,
    registrar,
    requirements,
)


from . import (
    narrowbundle2,
    narrowcommands,
    narrowrepo,
    narrowtemplates,
    narrowwirepeer,
)

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = b'ships-with-hg-core'

configtable = {}
configitem = registrar.configitem(configtable)
# Narrowhg *has* support for serving ellipsis nodes (which are used at
# least by Google's internal server), but that support is pretty
# fragile and has a lot of problems on real-world repositories that
# have complex graph topologies. This could probably be corrected, but
# absent someone needing the full support for ellipsis nodes in
# repositories with merges, it's unlikely this work will get done. As
# of this writining in late 2017, all repositories large enough for
# ellipsis nodes to be a hard requirement also enforce strictly linear
# history for other scaling reasons.
configitem(
    b'experimental',
    b'narrowservebrokenellipses',
    default=False,
    alias=[(b'narrow', b'serveellipses')],
)

# Export the commands table for Mercurial to see.
cmdtable = narrowcommands.table


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


def uisetup(ui):
    """Wraps user-facing mercurial commands with narrow-aware versions."""
    localrepo.featuresetupfuncs.add(featuresetup)
    narrowbundle2.setup()
    narrowcommands.setup()
    narrowwirepeer.uisetup()


def reposetup(ui, repo):
    """Wraps local repositories with narrow repo support."""
    if not repo.local():
        return

    repo.ui.setconfig(b'experimental', b'narrow', True, b'narrow-ext')
    if requirements.NARROW_REQUIREMENT in repo.requirements:
        narrowrepo.wraprepo(repo)
        narrowwirepeer.reposetup(repo)


templatekeyword = narrowtemplates.templatekeyword
revsetpredicate = narrowtemplates.revsetpredicate