hgext/automv.py

subrepo: fix a crash when archiving an svn or git subrepo

Only hgsubrepos have a repository attribute.  This is pretty hacky, but probably
the best we can do on stable.  Pushing the lfstatus check down into the wrapper
for hgsubrepo (and dropping the check for lfstatus at the top of
`hgsubrepoarchive()`) resulted in various test failures because:

  1) hgsubrepoarchive isn't returning the number of files archived at the
     bottom, resulting in an error about += NoneType
  2) These copypasta archive wrappers don't use progress bars
  3) Largefiles are *not* currently archived when using extdiff (68822b7cdd01),
     but pushing this context manager down into the subrepo resulted in it
     apparently doing so (as evidenced by progress bars being dropped)

The other uses of `lfstatus()` are not in the substate processing loop, so they
shouldn't be an issue.

I initially put testcases in this test for largefiles-{on,off}, and it flagged
a bunch of exit code differences for `cat` and `diff`, so I backed that off.

Differential Revision: https://phab.mercurial-scm.org/D7714

# 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(
    b'automv', b'similarity', default=95,
)


def extsetup(ui):
    entry = extensions.wrapcommand(commands.table, b'commit', mvcheck)
    entry[1].append(
        (b'', b'no-automv', None, _(b'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(b'no_automv', False)
    if not disabled:
        threshold = ui.configint(b'automv', b'similarity')
        if not 0 <= threshold <= 100:
            raise error.Abort(_(b'automv.similarity must be between 0 and 100'))
        if threshold > 0:
            match = scmutil.match(repo[None], pats, opts)
            added, removed = _interestingfiles(repo, match)
            uipathfn = scmutil.getuipathfn(repo, legacyrelativevalue=True)
            renames = _findrenames(
                repo, uipathfn, 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.added
    removed = stat.removed

    copy = copies.pathcopies(repo[b'.'], 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, uipathfn, 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(
                    _(b'detected move of %s as %s (%d%% similar)\n')
                    % (uipathfn(src), uipathfn(dst), score * 100)
                )
            renames[dst] = src
    if renames:
        repo.ui.status(_(b'detected move of %d files\n') % len(renames))
    return renames