bisect: avoid copying ancestor list for non-merge commits
During a bisection, hg needs to compute a list of all ancestors for every
candidate commit. This is accomplished via a bottom-up traversal of the set of
candidates, during which each revision's ancestor list is populated using the
ancestor list of its parent(s). Previously, this involved copying the entire
list, which could be very long in if the bisection range was large.
To help improve this, we can observe that each candidate commit is visited
exactly once, at which point its ancestor list is copied into its children's
lists and then dropped. In the case of non-merge commits, a commit's ancestor
list consists exactly of its parent's list plus itself. This means that we can
trivially reuse the parent's existing list for one of its non-merge children,
which avoids copying entirely if that commit is the parent's only child. This
makes bisections over linear ranges of commits much faster.
During some informal testing in the large publicly-available `mozilla-central`
repository, this noticeably sped up bisections over large ranges of history:
Setup:
$ cd mozilla-central
$ hg bisect --reset
$ hg bisect --good 0
$ hg log -r tip -T '{rev}\n'
628417
Test:
$ time hg bisect --bad tip --noupdate
Before:
real 3m35.927s
user 3m35.553s
sys 0m0.319s
After:
real 1m41.142s
user 1m40.810s
sys 0m0.285s
# 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 mercurial.i18n import _
from mercurial import (
cmdutil,
commands,
registrar,
)
cmdtable = {}
command = registrar.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 = b'ships-with-hg-core'
@command(
b'glog',
[
(
b'f',
b'follow',
None,
_(
b'follow changeset history, or file history across copies and renames'
),
),
(
b'',
b'follow-first',
None,
_(b'only follow the first parent of merge changesets (DEPRECATED)'),
),
(
b'd',
b'date',
b'',
_(b'show revisions matching date spec'),
_(b'DATE'),
),
(b'C', b'copies', None, _(b'show copied files')),
(
b'k',
b'keyword',
[],
_(b'do case-insensitive search for a given text'),
_(b'TEXT'),
),
(
b'r',
b'rev',
[],
_(b'show the specified revision or revset'),
_(b'REV'),
),
(
b'',
b'removed',
None,
_(b'include revisions where files were removed'),
),
(b'm', b'only-merges', None, _(b'show only merges (DEPRECATED)')),
(b'u', b'user', [], _(b'revisions committed by user'), _(b'USER')),
(
b'',
b'only-branch',
[],
_(
b'show only changesets within the given named branch (DEPRECATED)'
),
_(b'BRANCH'),
),
(
b'b',
b'branch',
[],
_(b'show changesets within the given named branch'),
_(b'BRANCH'),
),
(
b'P',
b'prune',
[],
_(b'do not display revision or any of its ancestors'),
_(b'REV'),
),
]
+ cmdutil.logopts
+ cmdutil.walkopts,
_(b'[OPTION]... [FILE]'),
helpcategory=command.CATEGORY_CHANGE_NAVIGATION,
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)