similar: compare between actual file contents for exact identity
Before this patch, similarity detection logic (for addremove and
automv) depends entirely on SHA-1 digesting. But this causes incorrect
rename detection, if:
- removing file A and adding file B occur at same committing, and
- SHA-1 hash values of file A and B are same
This may prevent security experts from managing sample files for
SHAttered issue in Mercurial repository, for example.
https://security.googleblog.com/2017/02/announcing-first-sha1-collision.html
https://shattered.it/
Hash collision itself isn't so serious for core repository
functionality of Mercurial, described by mpm as below, though.
https://www.mercurial-scm.org/wiki/mpm/SHA1
This patch compares between actual file contents after hash comparison
for exact identity.
Even after this patch, SHA-1 is still used, because it is reasonable
enough to quickly detect existence of "(almost) same" file.
- replacing SHA-1 causes decreasing performance, and
- replacement of it has ambiguity, yet
Getting content of removed file (= rfctx.data()) at each exact
comparison should be cheap enough, even though getting content of
added one costs much.
======= ============== =====================
file fctx data() reads from
======= ============== =====================
removed filectx in-memory revlog data
added workingfilectx storage
======= ============== =====================
# ASCII graph log extension for Mercurial
#
# Copyright 2007 Joel Rosdahl <joel@rosdahl.net>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''command to view revision graphs from a shell (DEPRECATED)
The functionality of this extension has been include in core Mercurial
since version 2.3. Please use :hg:`log -G ...` instead.
This extension adds a --graph option to the incoming, outgoing and log
commands. When this options is given, an ASCII representation of the
revision graph is also shown.
'''
from __future__ import absolute_import
from mercurial.i18n import _
from mercurial import (
cmdutil,
commands,
)
cmdtable = {}
command = cmdutil.command(cmdtable)
# 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 = 'ships-with-hg-core'
@command('glog',
[('f', 'follow', None,
_('follow changeset history, or file history across copies and renames')),
('', 'follow-first', None,
_('only follow the first parent of merge changesets (DEPRECATED)')),
('d', 'date', '', _('show revisions matching date spec'), _('DATE')),
('C', 'copies', None, _('show copied files')),
('k', 'keyword', [],
_('do case-insensitive search for a given text'), _('TEXT')),
('r', 'rev', [], _('show the specified revision or revset'), _('REV')),
('', 'removed', None, _('include revisions where files were removed')),
('m', 'only-merges', None, _('show only merges (DEPRECATED)')),
('u', 'user', [], _('revisions committed by user'), _('USER')),
('', 'only-branch', [],
_('show only changesets within the given named branch (DEPRECATED)'),
_('BRANCH')),
('b', 'branch', [],
_('show changesets within the given named branch'), _('BRANCH')),
('P', 'prune', [],
_('do not display revision or any of its ancestors'), _('REV')),
] + commands.logopts + commands.walkopts,
_('[OPTION]... [FILE]'),
inferrepo=True)
def glog(ui, repo, *pats, **opts):
"""show revision history alongside an ASCII revision graph
Print a revision history alongside a revision graph drawn with
ASCII characters.
Nodes printed as an @ character are parents of the working
directory.
This is an alias to :hg:`log -G`.
"""
opts['graph'] = True
return commands.log(ui, repo, *pats, **opts)