hgext/commitextras.py

dirstateguard: use mktemp-like functionality to generate the backup filenames

Previously these were generated with names like:
`dirstate.backup.commit.<memory address of dirstateguard>`

This could cause problems if two hg commands ran at the same time that used the
same memory address, (which is apparently not uncommon if chg is involved), as
memory addresses are not unique across processes.

This issue was reported in the post-review comments on
http://phab.mercurial-scm.org/D9952.

Differential Revision: https://phab.mercurial-scm.org/D10504

# commitextras.py
#
# Copyright 2013 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.

'''adds a new flag extras to commit (ADVANCED)'''

from __future__ import absolute_import

import re

from mercurial.i18n import _
from mercurial import (
    commands,
    error,
    extensions,
    registrar,
    util,
)

cmdtable = {}
command = registrar.command(cmdtable)
testedwith = b'ships-with-hg-core'

usedinternally = {
    b'amend_source',
    b'branch',
    b'close',
    b'histedit_source',
    b'topic',
    b'rebase_source',
    b'intermediate-source',
    b'__touch-noise__',
    b'source',
    b'transplant_source',
}


def extsetup(ui):
    entry = extensions.wrapcommand(commands.table, b'commit', _commit)
    options = entry[1]
    options.append(
        (
            b'',
            b'extra',
            [],
            _(b'set a changeset\'s extra values'),
            _(b"KEY=VALUE"),
        )
    )


def _commit(orig, ui, repo, *pats, **opts):
    if util.safehasattr(repo, 'unfiltered'):
        repo = repo.unfiltered()

    class repoextra(repo.__class__):
        def commit(self, *innerpats, **inneropts):
            extras = opts.get('extra')
            for raw in extras:
                if b'=' not in raw:
                    msg = _(
                        b"unable to parse '%s', should follow "
                        b"KEY=VALUE format"
                    )
                    raise error.Abort(msg % raw)
                k, v = raw.split(b'=', 1)
                if not k:
                    msg = _(b"unable to parse '%s', keys can't be empty")
                    raise error.Abort(msg % raw)
                if re.search(br'[^\w-]', k):
                    msg = _(
                        b"keys can only contain ascii letters, digits,"
                        b" '_' and '-'"
                    )
                    raise error.Abort(msg)
                if k in usedinternally:
                    msg = _(
                        b"key '%s' is used internally, can't be set "
                        b"manually"
                    )
                    raise error.Abort(msg % k)
                inneropts['extra'][k] = v
            return super(repoextra, self).commit(*innerpats, **inneropts)

    repo.__class__ = repoextra
    return orig(ui, repo, *pats, **opts)