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
# win32text.py - LF <-> CRLF/CR translation utilities for Windows/Mac users
#
# Copyright 2005, 2007-2009 Olivia Mackall <olivia@selenic.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''perform automatic newline conversion (DEPRECATED)
Deprecation: The win32text extension requires each user to configure
the extension again and again for each clone since the configuration
is not copied when cloning.
We have therefore made the ``eol`` as an alternative. The ``eol``
uses a version controlled file for its configuration and each clone
will therefore use the right settings from the start.
To perform automatic newline conversion, use::
[extensions]
win32text =
[encode]
** = cleverencode:
# or ** = macencode:
[decode]
** = cleverdecode:
# or ** = macdecode:
If not doing conversion, to make sure you do not commit CRLF/CR by accident::
[hooks]
pretxncommit.crlf = python:hgext.win32text.forbidcrlf
# or pretxncommit.cr = python:hgext.win32text.forbidcr
To do the same check on a server to prevent CRLF/CR from being
pushed or pulled::
[hooks]
pretxnchangegroup.crlf = python:hgext.win32text.forbidcrlf
# or pretxnchangegroup.cr = python:hgext.win32text.forbidcr
'''
import re
from mercurial.i18n import _
from mercurial.node import short
from mercurial import (
cmdutil,
extensions,
registrar,
)
from mercurial.utils import stringutil
# 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'
configtable = {}
configitem = registrar.configitem(configtable)
configitem(
b'win32text',
b'warn',
default=True,
)
# regexp for single LF without CR preceding.
re_single_lf = re.compile(b'(^|[^\r])\n', re.MULTILINE)
newlinestr = {b'\r\n': b'CRLF', b'\r': b'CR'}
filterstr = {b'\r\n': b'clever', b'\r': b'mac'}
def checknewline(s, newline, ui=None, repo=None, filename=None):
# warn if already has 'newline' in repository.
# it might cause unexpected eol conversion.
# see issue 302:
# https://bz.mercurial-scm.org/302
if newline in s and ui and filename and repo:
ui.warn(
_(
b'WARNING: %s already has %s line endings\n'
b'and does not need EOL conversion by the win32text plugin.\n'
b'Before your next commit, please reconsider your '
b'encode/decode settings in \nMercurial.ini or %s.\n'
)
% (filename, newlinestr[newline], repo.vfs.join(b'hgrc'))
)
def dumbdecode(s, cmd, **kwargs):
checknewline(s, b'\r\n', **kwargs)
# replace single LF to CRLF
return re_single_lf.sub(b'\\1\r\n', s)
def dumbencode(s, cmd):
return s.replace(b'\r\n', b'\n')
def macdumbdecode(s, cmd, **kwargs):
checknewline(s, b'\r', **kwargs)
return s.replace(b'\n', b'\r')
def macdumbencode(s, cmd):
return s.replace(b'\r', b'\n')
def cleverdecode(s, cmd, **kwargs):
if not stringutil.binary(s):
return dumbdecode(s, cmd, **kwargs)
return s
def cleverencode(s, cmd):
if not stringutil.binary(s):
return dumbencode(s, cmd)
return s
def macdecode(s, cmd, **kwargs):
if not stringutil.binary(s):
return macdumbdecode(s, cmd, **kwargs)
return s
def macencode(s, cmd):
if not stringutil.binary(s):
return macdumbencode(s, cmd)
return s
_filters = {
b'dumbdecode:': dumbdecode,
b'dumbencode:': dumbencode,
b'cleverdecode:': cleverdecode,
b'cleverencode:': cleverencode,
b'macdumbdecode:': macdumbdecode,
b'macdumbencode:': macdumbencode,
b'macdecode:': macdecode,
b'macencode:': macencode,
}
def forbidnewline(ui, repo, hooktype, node, newline, **kwargs):
halt = False
seen = set()
# we try to walk changesets in reverse order from newest to
# oldest, so that if we see a file multiple times, we take the
# newest version as canonical. this prevents us from blocking a
# changegroup that contains an unacceptable commit followed later
# by a commit that fixes the problem.
tip = repo[b'tip']
for rev in range(repo.changelog.tiprev(), repo[node].rev() - 1, -1):
c = repo[rev]
for f in c.files():
if f in seen or f not in tip or f not in c:
continue
seen.add(f)
data = c[f].data()
if not stringutil.binary(data) and newline in data:
if not halt:
ui.warn(
_(
b'attempt to commit or push text file(s) '
b'using %s line endings\n'
)
% newlinestr[newline]
)
ui.warn(_(b'in %s: %s\n') % (short(c.node()), f))
halt = True
if halt and hooktype == b'pretxnchangegroup':
crlf = newlinestr[newline].lower()
filter = filterstr[newline]
ui.warn(
_(
b'\nTo prevent this mistake in your local repository,\n'
b'add to Mercurial.ini or .hg/hgrc:\n'
b'\n'
b'[hooks]\n'
b'pretxncommit.%s = python:hgext.win32text.forbid%s\n'
b'\n'
b'and also consider adding:\n'
b'\n'
b'[extensions]\n'
b'win32text =\n'
b'[encode]\n'
b'** = %sencode:\n'
b'[decode]\n'
b'** = %sdecode:\n'
)
% (crlf, crlf, filter, filter)
)
return halt
def forbidcrlf(ui, repo, hooktype, node, **kwargs):
return forbidnewline(ui, repo, hooktype, node, b'\r\n', **kwargs)
def forbidcr(ui, repo, hooktype, node, **kwargs):
return forbidnewline(ui, repo, hooktype, node, b'\r', **kwargs)
def reposetup(ui, repo):
if not repo.local():
return
for name, fn in _filters.items():
repo.adddatafilter(name, fn)
def wrap_revert(orig, repo, ctx, names, uipathfn, actions, *args, **kwargs):
# reset dirstate cache for file we touch
ds = repo.dirstate
with ds.parentchange():
for filename in actions[b'revert'][0]:
entry = ds.get_entry(filename)
if entry is not None:
if entry.p1_tracked:
ds.update_file(
filename,
entry.tracked,
p1_tracked=True,
p2_info=entry.p2_info,
)
return orig(repo, ctx, names, uipathfn, actions, *args, **kwargs)
def extsetup(ui):
# deprecated config: win32text.warn
if ui.configbool(b'win32text', b'warn'):
ui.warn(
_(
b"win32text is deprecated: "
b"https://mercurial-scm.org/wiki/Win32TextExtension\n"
)
)
extensions.wrapfunction(cmdutil, '_performrevert', wrap_revert)