view mercurial/node.py @ 29352:37c7f9fb7040

localrepo: make restoring from backup at rollback avoid ambiguity of file stat

Rollback of previous transaction restores contents of files below by
renaming from 'undo.*' file. If renaming keeps ctime, mtime and size
of a file, restoring is overlooked, and old contents cached before
restoring isn't invalidated as expected.

  - .hg/bookmarks
  - .hg/phaseroots

To avoid ambiguity of file stat at restoring, this patch invokes
vfs.rename() with checkambig=True.

BTW, .hg/dirstate is also restored at rollback. But it is restored by
dirstate.restorebackup(), and previous patch already made it invoke
vfs.rename() with checkambig=True.

This patch is a part of "Exact Cache Validation Plan":

    https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan

# node.py - basic nodeid manipulation for mercurial
#
# Copyright 2005, 2006 Matt Mackall <[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

import binascii

# This ugly style has a noticeable effect in manifest parsing
hex = binascii.hexlify
bin = binascii.unhexlify

nullrev = -1
nullid = b"\0" * 20
nullhex = hex(nullid)

# pseudo identifiers for working directory
# (they are experimental, so don't add too many dependencies on them)
wdirrev = 0x7fffffff
wdirid = b"\xff" * 20

def short(node):
    return hex(node[:6])