Mercurial > hg-stable
view tests/hghave.py @ 26457:7e81305092a0
demandimport: replace more references to _demandmod instances
_demandmod instances may be referenced by multiple importing modules.
Before this patch, the _demandmod instance only maintained a reference
to its first consumer when using the "from X import Y" syntax. This is
because we only created a single _demandmod instance (attached to the
parent X module). If multiple modules A and B performed
"from X import Y", we'd produce a single _demandmod instance
"demandmod" with the following references:
X.Y = <demandmod>
A.Y = <demandmod>
B.Y = <demandmod>
The locals from the first consumer (A) would be stored in <demandmod1>.
When <demandmod1> was loaded, we'd look at the locals for the first
consumer and replace the symbol, if necessary. This resulted in state:
X.Y = <module>
A.Y = <module>
B.Y = <demandmod>
B's reference to Y wasn't updated and was still using the proxy object
because we just didn't record that B had a reference to <demandmod> that
needed updating!
With this patch, we add support for tracking which modules in addition
to the initial importer have a reference to the _demandmod instance and
we replace those references at module load time.
In the case of posix.py, this fixes an issue where the "encoding" module
was being proxied, resulting in hundreds of thousands of
__getattribute__ lookups on the _demandmod instance during dirstate
operations on mozilla-central, speeding up execution by many
milliseconds. There are likely several other operation that benefit from
this change as well.
The new mechanism isn't perfect: references in locals (not globals) may
likely linger. So, if there is an import inside a function and a symbol
from that module is used in a hot loop, we could have unwanted overhead
from proxying through _demandmod. Non-global imports are discouraged
anyway. So hopefully this isn't a big deal in practice. We could
potentially deploy a code checker that bans use of attribute lookups of
function-level-imported modules inside loops.
This deficiency in theory could be avoided by storing the set of globals
and locals dicts to update in the _demandmod instance. However, I tried
this and it didn't work. One reason is that some globals are _demandmod
instances. We could work around this, but it's a bit more work. There
also might be other module import foo at play. The solution as
implemented is better than what we had and IMO is good enough for the
time being.
It's worth noting that this sub-optimal behavior was made worse by the
introduction of absolute_import and its recommended "from . import X"
syntax for importing modules from the "mercurial" package. If we ever
wrote performance tests, measuring the amount of module imports and
__getattribute__ proxy calls through _demandmod instances would be
something I'd have it check.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 04 Oct 2015 11:17:43 -0700 |
parents | ca9bb66c80e9 |
children | 0f76c64f5cc3 |
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import errno import os import re import socket import stat import subprocess import sys import tempfile tempprefix = 'hg-hghave-' checks = { "true": (lambda: True, "yak shaving"), "false": (lambda: False, "nail clipper"), } def check(name, desc): def decorator(func): checks[name] = (func, desc) return func return decorator def checkfeatures(features): result = { 'error': [], 'missing': [], 'skipped': [], } for feature in features: negate = feature.startswith('no-') if negate: feature = feature[3:] if feature not in checks: result['missing'].append(feature) continue check, desc = checks[feature] try: available = check() except Exception: result['error'].append('hghave check failed: %s' % feature) continue if not negate and not available: result['skipped'].append('missing feature: %s' % desc) elif negate and available: result['skipped'].append('system supports %s' % desc) return result def require(features): """Require that features are available, exiting if not.""" result = checkfeatures(features) for missing in result['missing']: sys.stderr.write('skipped: unknown feature: %s\n' % missing) for msg in result['skipped']: sys.stderr.write('skipped: %s\n' % msg) for msg in result['error']: sys.stderr.write('%s\n' % msg) if result['missing']: sys.exit(2) if result['skipped'] or result['error']: sys.exit(1) def matchoutput(cmd, regexp, ignorestatus=False): """Return True if cmd executes successfully and its output is matched by the supplied regular expression. """ r = re.compile(regexp) try: p = subprocess.Popen( cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT) except OSError as e: if e.errno != errno.ENOENT: raise ret = -1 ret = p.wait() s = p.stdout.read() return (ignorestatus or not ret) and r.search(s) @check("baz", "GNU Arch baz client") def has_baz(): return matchoutput('baz --version 2>&1', r'baz Bazaar version') @check("bzr", "Canonical's Bazaar client") def has_bzr(): try: import bzrlib return bzrlib.__doc__ is not None except ImportError: return False @check("bzr114", "Canonical's Bazaar client >= 1.14") def has_bzr114(): try: import bzrlib return (bzrlib.__doc__ is not None and bzrlib.version_info[:2] >= (1, 14)) except ImportError: return False @check("cvs", "cvs client/server") def has_cvs(): re = r'Concurrent Versions System.*?server' return matchoutput('cvs --version 2>&1', re) and not has_msys() @check("cvs112", "cvs client/server >= 1.12") def has_cvs112(): re = r'Concurrent Versions System \(CVS\) 1.12.*?server' return matchoutput('cvs --version 2>&1', re) and not has_msys() @check("darcs", "darcs client") def has_darcs(): return matchoutput('darcs --version', r'2\.[2-9]', True) @check("mtn", "monotone client (>= 1.0)") def has_mtn(): return matchoutput('mtn --version', r'monotone', True) and not matchoutput( 'mtn --version', r'monotone 0\.', True) @check("eol-in-paths", "end-of-lines in paths") def has_eol_in_paths(): try: fd, path = tempfile.mkstemp(dir='.', prefix=tempprefix, suffix='\n\r') os.close(fd) os.remove(path) return True except (IOError, OSError): return False @check("execbit", "executable bit") def has_executablebit(): try: EXECFLAGS = stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH fh, fn = tempfile.mkstemp(dir='.', prefix=tempprefix) try: os.close(fh) m = os.stat(fn).st_mode & 0o777 new_file_has_exec = m & EXECFLAGS os.chmod(fn, m ^ EXECFLAGS) exec_flags_cannot_flip = ((os.stat(fn).st_mode & 0o777) == m) finally: os.unlink(fn) except (IOError, OSError): # we don't care, the user probably won't be able to commit anyway return False return not (new_file_has_exec or exec_flags_cannot_flip) @check("icasefs", "case insensitive file system") def has_icasefs(): # Stolen from mercurial.util fd, path = tempfile.mkstemp(dir='.', prefix=tempprefix) os.close(fd) try: s1 = os.stat(path) d, b = os.path.split(path) p2 = os.path.join(d, b.upper()) if path == p2: p2 = os.path.join(d, b.lower()) try: s2 = os.stat(p2) return s2 == s1 except OSError: return False finally: os.remove(path) @check("fifo", "named pipes") def has_fifo(): if getattr(os, "mkfifo", None) is None: return False name = tempfile.mktemp(dir='.', prefix=tempprefix) try: os.mkfifo(name) os.unlink(name) return True except OSError: return False @check("killdaemons", 'killdaemons.py support') def has_killdaemons(): return True @check("cacheable", "cacheable filesystem") def has_cacheable_fs(): from mercurial import util fd, path = tempfile.mkstemp(dir='.', prefix=tempprefix) os.close(fd) try: return util.cachestat(path).cacheable() finally: os.remove(path) @check("lsprof", "python lsprof module") def has_lsprof(): try: import _lsprof _lsprof.Profiler # silence unused import warning return True except ImportError: return False @check("gettext", "GNU Gettext (msgfmt)") def has_gettext(): return matchoutput('msgfmt --version', 'GNU gettext-tools') @check("git", "git command line client") def has_git(): return matchoutput('git --version 2>&1', r'^git version') @check("docutils", "Docutils text processing library") def has_docutils(): try: from docutils.core import publish_cmdline publish_cmdline # silence unused import return True except ImportError: return False def getsvnversion(): m = matchoutput('svn --version --quiet 2>&1', r'^(\d+)\.(\d+)') if not m: return (0, 0) return (int(m.group(1)), int(m.group(2))) @check("svn15", "subversion client and admin tools >= 1.5") def has_svn15(): return getsvnversion() >= (1, 5) @check("svn13", "subversion client and admin tools >= 1.3") def has_svn13(): return getsvnversion() >= (1, 3) @check("svn", "subversion client and admin tools") def has_svn(): return matchoutput('svn --version 2>&1', r'^svn, version') and \ matchoutput('svnadmin --version 2>&1', r'^svnadmin, version') @check("svn-bindings", "subversion python bindings") def has_svn_bindings(): try: import svn.core version = svn.core.SVN_VER_MAJOR, svn.core.SVN_VER_MINOR if version < (1, 4): return False return True except ImportError: return False @check("p4", "Perforce server and client") def has_p4(): return (matchoutput('p4 -V', r'Rev\. P4/') and matchoutput('p4d -V', r'Rev\. P4D/')) @check("symlink", "symbolic links") def has_symlink(): if getattr(os, "symlink", None) is None: return False name = tempfile.mktemp(dir='.', prefix=tempprefix) try: os.symlink(".", name) os.unlink(name) return True except (OSError, AttributeError): return False @check("hardlink", "hardlinks") def has_hardlink(): from mercurial import util fh, fn = tempfile.mkstemp(dir='.', prefix=tempprefix) os.close(fh) name = tempfile.mktemp(dir='.', prefix=tempprefix) try: util.oslink(fn, name) os.unlink(name) return True except OSError: return False finally: os.unlink(fn) @check("tla", "GNU Arch tla client") def has_tla(): return matchoutput('tla --version 2>&1', r'The GNU Arch Revision') @check("gpg", "gpg client") def has_gpg(): return matchoutput('gpg --version 2>&1', r'GnuPG') @check("unix-permissions", "unix-style permissions") def has_unix_permissions(): d = tempfile.mkdtemp(dir='.', prefix=tempprefix) try: fname = os.path.join(d, 'foo') for umask in (0o77, 0o07, 0o22): os.umask(umask) f = open(fname, 'w') f.close() mode = os.stat(fname).st_mode os.unlink(fname) if mode & 0o777 != ~umask & 0o666: return False return True finally: os.rmdir(d) @check("unix-socket", "AF_UNIX socket family") def has_unix_socket(): return getattr(socket, 'AF_UNIX', None) is not None @check("root", "root permissions") def has_root(): return getattr(os, 'geteuid', None) and os.geteuid() == 0 @check("pyflakes", "Pyflakes python linter") def has_pyflakes(): return matchoutput("sh -c \"echo 'import re' 2>&1 | pyflakes\"", r"<stdin>:1: 're' imported but unused", True) @check("pygments", "Pygments source highlighting library") def has_pygments(): try: import pygments pygments.highlight # silence unused import warning return True except ImportError: return False @check("json", "some json module available") def has_json(): try: import json json.dumps return True except ImportError: try: import simplejson as json json.dumps return True except ImportError: pass return False @check("outer-repo", "outer repo") def has_outer_repo(): # failing for other reasons than 'no repo' imply that there is a repo return not matchoutput('hg root 2>&1', r'abort: no repository found', True) @check("ssl", ("(python >= 2.6 ssl module and python OpenSSL) " "OR python >= 2.7.9 ssl")) def has_ssl(): try: import ssl if getattr(ssl, 'create_default_context', False): return True import OpenSSL OpenSSL.SSL.Context return True except ImportError: return False @check("sslcontext", "python >= 2.7.9 ssl") def has_sslcontext(): try: import ssl ssl.SSLContext return True except (ImportError, AttributeError): return False @check("defaultcacerts", "can verify SSL certs by system's CA certs store") def has_defaultcacerts(): from mercurial import sslutil return sslutil._defaultcacerts() != '!' @check("windows", "Windows") def has_windows(): return os.name == 'nt' @check("system-sh", "system() uses sh") def has_system_sh(): return os.name != 'nt' @check("serve", "platform and python can manage 'hg serve -d'") def has_serve(): return os.name != 'nt' # gross approximation @check("test-repo", "running tests from repository") def has_test_repo(): t = os.environ["TESTDIR"] return os.path.isdir(os.path.join(t, "..", ".hg")) @check("tic", "terminfo compiler and curses module") def has_tic(): try: import curses curses.COLOR_BLUE return matchoutput('test -x "`which tic`"', '') except ImportError: return False @check("msys", "Windows with MSYS") def has_msys(): return os.getenv('MSYSTEM') @check("aix", "AIX") def has_aix(): return sys.platform.startswith("aix") @check("osx", "OS X") def has_osx(): return sys.platform == 'darwin' @check("docker", "docker support") def has_docker(): pat = r'A self-sufficient runtime for linux containers\.' if matchoutput('docker --help', pat): if 'linux' not in sys.platform: # TODO: in theory we should be able to test docker-based # package creation on non-linux using boot2docker, but in # practice that requires extra coordination to make sure # $TESTTEMP is going to be visible at the same path to the # boot2docker VM. If we figure out how to verify that, we # can use the following instead of just saying False: # return 'DOCKER_HOST' in os.environ return False return True return False @check("debhelper", "debian packaging tools") def has_debhelper(): dpkg = matchoutput('dpkg --version', "Debian `dpkg' package management program") dh = matchoutput('dh --help', 'dh is a part of debhelper.', ignorestatus=True) dh_py2 = matchoutput('dh_python2 --help', 'other supported Python versions') return dpkg and dh and dh_py2 @check("absimport", "absolute_import in __future__") def has_absimport(): import __future__ from mercurial import util return util.safehasattr(__future__, "absolute_import") @check("py3k", "running with Python 3.x") def has_py3k(): return 3 == sys.version_info[0] @check("pure", "running with pure Python code") def has_pure(): return os.environ.get("HGTEST_RUN_TESTS_PURE") == "--pure" @check("slow", "allow slow tests") def has_slow(): return os.environ.get('HGTEST_SLOW') == 'slow'