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
# hook.py - hook support for mercurial
#
# Copyright 2007 Olivia Mackall <olivia@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
import contextlib
import errno
import os
import sys
from .i18n import _
from .pycompat import getattr
from . import (
demandimport,
encoding,
error,
extensions,
pycompat,
util,
)
from .utils import (
procutil,
resourceutil,
stringutil,
)
def pythonhook(ui, repo, htype, hname, funcname, args, throw):
"""call python hook. hook is callable object, looked up as
name in python module. if callable returns "true", hook
fails, else passes. if hook raises exception, treated as
hook failure. exception propagates if throw is "true".
reason for "true" meaning "hook failed" is so that
unmodified commands (e.g. mercurial.commands.update) can
be run as hooks without wrappers to convert return values."""
if callable(funcname):
obj = funcname
funcname = pycompat.sysbytes(obj.__module__ + "." + obj.__name__)
else:
d = funcname.rfind(b'.')
if d == -1:
raise error.HookLoadError(
_(b'%s hook is invalid: "%s" not in a module')
% (hname, funcname)
)
modname = funcname[:d]
oldpaths = sys.path
if resourceutil.mainfrozen():
# binary installs require sys.path manipulation
modpath, modfile = os.path.split(modname)
if modpath and modfile:
sys.path = sys.path[:] + [modpath]
modname = modfile
with demandimport.deactivated():
try:
obj = __import__(pycompat.sysstr(modname))
except (ImportError, SyntaxError):
e1 = sys.exc_info()
try:
# extensions are loaded with hgext_ prefix
obj = __import__("hgext_%s" % pycompat.sysstr(modname))
except (ImportError, SyntaxError):
e2 = sys.exc_info()
if ui.tracebackflag:
ui.warn(
_(
b'exception from first failed import '
b'attempt:\n'
)
)
ui.traceback(e1)
if ui.tracebackflag:
ui.warn(
_(
b'exception from second failed import '
b'attempt:\n'
)
)
ui.traceback(e2)
if not ui.tracebackflag:
tracebackhint = _(
b'run with --traceback for stack trace'
)
else:
tracebackhint = None
raise error.HookLoadError(
_(b'%s hook is invalid: import of "%s" failed')
% (hname, modname),
hint=tracebackhint,
)
sys.path = oldpaths
try:
for p in funcname.split(b'.')[1:]:
obj = getattr(obj, p)
except AttributeError:
raise error.HookLoadError(
_(b'%s hook is invalid: "%s" is not defined')
% (hname, funcname)
)
if not callable(obj):
raise error.HookLoadError(
_(b'%s hook is invalid: "%s" is not callable')
% (hname, funcname)
)
ui.note(_(b"calling hook %s: %s\n") % (hname, funcname))
starttime = util.timer()
try:
r = obj(ui=ui, repo=repo, hooktype=htype, **pycompat.strkwargs(args))
except Exception as exc:
if isinstance(exc, error.Abort):
ui.warn(_(b'error: %s hook failed: %s\n') % (hname, exc.args[0]))
else:
ui.warn(
_(b'error: %s hook raised an exception: %s\n')
% (hname, stringutil.forcebytestr(exc))
)
if throw:
raise
if not ui.tracebackflag:
ui.warn(_(b'(run with --traceback for stack trace)\n'))
ui.traceback()
return True, True
finally:
duration = util.timer() - starttime
ui.log(
b'pythonhook',
b'pythonhook-%s: %s finished in %0.2f seconds\n',
htype,
funcname,
duration,
)
if r:
if throw:
raise error.HookAbort(_(b'%s hook failed') % hname)
ui.warn(_(b'warning: %s hook failed\n') % hname)
return r, False
def _exthook(ui, repo, htype, name, cmd, args, throw):
starttime = util.timer()
env = {}
# make in-memory changes visible to external process
if repo is not None:
tr = repo.currenttransaction()
repo.dirstate.write(tr)
if tr and tr.writepending():
env[b'HG_PENDING'] = repo.root
env[b'HG_HOOKTYPE'] = htype
env[b'HG_HOOKNAME'] = name
if ui.config(b'hooks', b'%s:run-with-plain' % name) == b'auto':
plain = ui.plain()
else:
plain = ui.configbool(b'hooks', b'%s:run-with-plain' % name)
if plain:
env[b'HGPLAIN'] = b'1'
else:
env[b'HGPLAIN'] = b''
for k, v in args.items():
# transaction changes can accumulate MBs of data, so skip it
# for external hooks
if k == b'changes':
continue
if callable(v):
v = v()
if isinstance(v, (dict, list)):
v = stringutil.pprint(v)
env[b'HG_' + k.upper()] = v
if ui.configbool(b'hooks', b'tonative.%s' % name, False):
oldcmd = cmd
cmd = procutil.shelltonative(cmd, env)
if cmd != oldcmd:
ui.note(_(b'converting hook "%s" to native\n') % name)
ui.note(_(b"running hook %s: %s\n") % (name, cmd))
if repo:
cwd = repo.root
else:
cwd = encoding.getcwd()
r = ui.system(cmd, environ=env, cwd=cwd, blockedtag=b'exthook-%s' % (name,))
duration = util.timer() - starttime
ui.log(
b'exthook',
b'exthook-%s: %s finished in %0.2f seconds\n',
name,
cmd,
duration,
)
if r:
desc = procutil.explainexit(r)
if throw:
raise error.HookAbort(_(b'%s hook %s') % (name, desc))
ui.warn(_(b'warning: %s hook %s\n') % (name, desc))
return r
# represent an untrusted hook command
_fromuntrusted = object()
def _allhooks(ui):
"""return a list of (hook-id, cmd) pairs sorted by priority"""
hooks = _hookitems(ui)
# Be careful in this section, propagating the real commands from untrusted
# sources would create a security vulnerability, make sure anything altered
# in that section uses "_fromuntrusted" as its command.
untrustedhooks = _hookitems(ui, _untrusted=True)
for name, value in untrustedhooks.items():
trustedvalue = hooks.get(name, ((), (), name, _fromuntrusted))
if value != trustedvalue:
(lp, lo, lk, lv) = trustedvalue
hooks[name] = (lp, lo, lk, _fromuntrusted)
# (end of the security sensitive section)
return [(k, v) for p, o, k, v in sorted(hooks.values())]
def _hookitems(ui, _untrusted=False):
"""return all hooks items ready to be sorted"""
hooks = {}
for name, cmd in ui.configitems(b'hooks', untrusted=_untrusted):
if (
name.startswith(b'priority.')
or name.startswith(b'tonative.')
or b':' in name
):
continue
priority = ui.configint(b'hooks', b'priority.%s' % name, 0)
hooks[name] = ((-priority,), (len(hooks),), name, cmd)
return hooks
_redirect = False
def redirect(state):
global _redirect
_redirect = state
def hashook(ui, htype):
"""return True if a hook is configured for 'htype'"""
if not ui.callhooks:
return False
for hname, cmd in _allhooks(ui):
if hname.split(b'.')[0] == htype and cmd:
return True
return False
def hook(ui, repo, htype, throw=False, **args):
if not ui.callhooks:
return False
hooks = []
for hname, cmd in _allhooks(ui):
if hname.split(b'.')[0] == htype and cmd:
hooks.append((hname, cmd))
res = runhooks(ui, repo, htype, hooks, throw=throw, **args)
r = False
for hname, cmd in hooks:
r = res[hname][0] or r
return r
@contextlib.contextmanager
def redirect_stdio():
"""Redirects stdout to stderr, if possible."""
oldstdout = -1
try:
if _redirect:
try:
stdoutno = procutil.stdout.fileno()
stderrno = procutil.stderr.fileno()
# temporarily redirect stdout to stderr, if possible
if stdoutno >= 0 and stderrno >= 0:
procutil.stdout.flush()
oldstdout = os.dup(stdoutno)
os.dup2(stderrno, stdoutno)
except (OSError, AttributeError):
# files seem to be bogus, give up on redirecting (WSGI, etc)
pass
yield
finally:
# The stderr is fully buffered on Windows when connected to a pipe.
# A forcible flush is required to make small stderr data in the
# remote side available to the client immediately.
try:
procutil.stderr.flush()
except IOError as err:
if err.errno not in (errno.EPIPE, errno.EIO, errno.EBADF):
raise error.StdioError(err)
if _redirect and oldstdout >= 0:
try:
procutil.stdout.flush() # write hook output to stderr fd
except IOError as err:
if err.errno not in (errno.EPIPE, errno.EIO, errno.EBADF):
raise error.StdioError(err)
os.dup2(oldstdout, stdoutno)
os.close(oldstdout)
def runhooks(ui, repo, htype, hooks, throw=False, **args):
args = pycompat.byteskwargs(args)
res = {}
with redirect_stdio():
for hname, cmd in hooks:
if cmd is _fromuntrusted:
if throw:
raise error.HookAbort(
_(b'untrusted hook %s not executed') % hname,
hint=_(b"see 'hg help config.trusted'"),
)
ui.warn(_(b'warning: untrusted hook %s not executed\n') % hname)
r = 1
raised = False
elif callable(cmd):
r, raised = pythonhook(ui, repo, htype, hname, cmd, args, throw)
elif cmd.startswith(b'python:'):
if cmd.count(b':') >= 2:
path, cmd = cmd[7:].rsplit(b':', 1)
path = util.expandpath(path)
if repo:
path = os.path.join(repo.root, path)
try:
mod = extensions.loadpath(path, b'hghook.%s' % hname)
except Exception:
ui.write(_(b"loading %s hook failed:\n") % hname)
raise
hookfn = getattr(mod, cmd)
else:
hookfn = cmd[7:].strip()
r, raised = pythonhook(
ui, repo, htype, hname, hookfn, args, throw
)
else:
r = _exthook(ui, repo, htype, hname, cmd, args, throw)
raised = False
res[hname] = r, raised
return res