procutil: always waiting on child processes to prevent zombies with 'hg serve'
When runbgcommand is invoked by an extension with ensurestart=False, we never
called waitpid - which is fine in most cases, except if that's happening on a
command server (e.g. chg), in which case the child defunct process will just
sit there for as long as the server is running.
The actual semantics of SIGCHLD signal handling is a lot more complex than
it seems, and the POSIX standard *seems* to read that it's ignored by default
and everything would just work without the waitpid if we're not listening for
it, but the truth is that it's only ignored if we *explicitly* set it to
SIG_IGN. We further cannot set it to SIG_IGN or to a catch-all handler across
all of 'hg serve', because Python's suprocess.Popen relies on that signal,
and a few specific parts of hg also set custom handlers, so instead we wait
for specific PIDs in dedicated threads.
I did a poor-man's benchmark of the thread creation and it seems to take
about 1ms, which is way better than the 20+ms from ensurestart=True.
Differential Revision: https://phab.mercurial-scm.org/D8497
# 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,
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)