view hgext/automv.py @ 37295:45b39c69fae0

wireproto: separate commands tables for version 1 and 2 commands

We can't easily reuse existing command handlers for version 2
commands because the response types will be different. e.g. many
commands return nodes encoded as hex. Our new wire protocol is
binary safe, so we'll wish to encode nodes as binary.

We /could/ teach each command handler to look at the protocol
handler and change behavior based on the version in use. However,
this would make logic a bit unwieldy over time and would make
it harder to design a unified protocol handler interface. I think
it's better to create a clean break between version 1 and version 2
of commands on the server.

What I imagine happening is we will have separate @wireprotocommand
functions for each protocol generation. Those functions will parse the
request, dispatch to a common function to process it, then generate
the response in its own, transport-specific manner.

This commit establishes a separate table for tracking version 1
commands from version 2 commands. The HTTP server pieces have been
updated to use this new table.

Most commands are marked as both version 1 and version 2, so there is
little practical impact to this change.

A side-effect of this change is we now rely on transport registration
in wireprototypes.TRANSPORTS and certain properties of the protocol
interface. So a test had to be updated to conform.

Differential Revision: https://phab.mercurial-scm.org/D2982

# automv.py
#
# Copyright 2013-2016 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""check for unrecorded moves at commit time (EXPERIMENTAL)

This extension checks at commit/amend time if any of the committed files
comes from an unrecorded mv.

The threshold at which a file is considered a move can be set with the
``automv.similarity`` config option. This option takes a percentage between 0
(disabled) and 100 (files must be identical), the default is 95.

"""

# Using 95 as a default similarity is based on an analysis of the mercurial
# repositories of the cpython, mozilla-central & mercurial repositories, as
# well as 2 very large facebook repositories. At 95 50% of all potential
# missed moves would be caught, as well as correspond with 87% of all
# explicitly marked moves.  Together, 80% of moved files are 95% similar or
# more.
#
# See http://markmail.org/thread/5pxnljesvufvom57 for context.

from __future__ import absolute_import

from mercurial.i18n import _
from mercurial import (
    commands,
    copies,
    error,
    extensions,
    pycompat,
    registrar,
    scmutil,
    similar
)

configtable = {}
configitem = registrar.configitem(configtable)

configitem('automv', 'similarity',
    default=95,
)

def extsetup(ui):
    entry = extensions.wrapcommand(
        commands.table, 'commit', mvcheck)
    entry[1].append(
        ('', 'no-automv', None,
         _('disable automatic file move detection')))

def mvcheck(orig, ui, repo, *pats, **opts):
    """Hook to check for moves at commit time"""
    opts = pycompat.byteskwargs(opts)
    renames = None
    disabled = opts.pop('no_automv', False)
    if not disabled:
        threshold = ui.configint('automv', 'similarity')
        if not 0 <= threshold <= 100:
            raise error.Abort(_('automv.similarity must be between 0 and 100'))
        if threshold > 0:
            match = scmutil.match(repo[None], pats, opts)
            added, removed = _interestingfiles(repo, match)
            renames = _findrenames(repo, match, added, removed,
                                   threshold / 100.0)

    with repo.wlock():
        if renames is not None:
            scmutil._markchanges(repo, (), (), renames)
        return orig(ui, repo, *pats, **pycompat.strkwargs(opts))

def _interestingfiles(repo, matcher):
    """Find what files were added or removed in this commit.

    Returns a tuple of two lists: (added, removed). Only files not *already*
    marked as moved are included in the added list.

    """
    stat = repo.status(match=matcher)
    added = stat[1]
    removed = stat[2]

    copy = copies._forwardcopies(repo['.'], repo[None], matcher)
    # remove the copy files for which we already have copy info
    added = [f for f in added if f not in copy]

    return added, removed

def _findrenames(repo, matcher, added, removed, similarity):
    """Find what files in added are really moved files.

    Any file named in removed that is at least similarity% similar to a file
    in added is seen as a rename.

    """
    renames = {}
    if similarity > 0:
        for src, dst, score in similar.findrenames(
                repo, added, removed, similarity):
            if repo.ui.verbose:
                repo.ui.status(
                    _('detected move of %s as %s (%d%% similar)\n') % (
                        matcher.rel(src), matcher.rel(dst), score * 100))
            renames[dst] = src
    if renames:
        repo.ui.status(_('detected move of %d files\n') % len(renames))
    return renames