procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
#!/usr/bin/env python3
# fsmonitor-run-tests.py - Run Mercurial tests with fsmonitor enabled
#
# Copyright 2017 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
#
# This is a wrapper around run-tests.py that spins up an isolated instance of
# Watchman and runs the Mercurial tests against it. This ensures that the global
# version of Watchman isn't affected by anything this test does.
import argparse
import contextlib
import json
import os
import shutil
import subprocess
import sys
import tempfile
import uuid
osenvironb = getattr(os, 'environb', os.environ)
if sys.version_info > (3, 5, 0):
PYTHON3 = True
def _sys2bytes(p):
return p.encode('utf-8')
elif sys.version_info >= (3, 0, 0):
print(
'%s is only supported on Python 3.5+ and 2.7, not %s'
% (sys.argv[0], '.'.join(str(v) for v in sys.version_info[:3]))
)
sys.exit(70) # EX_SOFTWARE from `man 3 sysexit`
else:
PYTHON3 = False
# In python 2.x, path operations are generally done using
# bytestrings by default, so we don't have to do any extra
# fiddling there. We define the wrapper functions anyway just to
# help keep code consistent between platforms.
def _sys2bytes(p):
return p
def getparser():
"""Obtain the argument parser used by the CLI."""
parser = argparse.ArgumentParser(
description='Run tests with fsmonitor enabled.',
epilog='Unrecognized options are passed to run-tests.py.',
)
# - keep these sorted
# - none of these options should conflict with any in run-tests.py
parser.add_argument(
'--keep-fsmonitor-tmpdir',
action='store_true',
help='keep temporary directory with fsmonitor state',
)
parser.add_argument(
'--watchman',
help='location of watchman binary (default: watchman in PATH)',
default='watchman',
)
return parser
@contextlib.contextmanager
def watchman(args):
basedir = tempfile.mkdtemp(prefix='hg-fsmonitor')
try:
# Much of this configuration is borrowed from Watchman's test harness.
cfgfile = os.path.join(basedir, 'config.json')
# TODO: allow setting a config
with open(cfgfile, 'w') as f:
f.write(json.dumps({}))
logfile = os.path.join(basedir, 'log')
clilogfile = os.path.join(basedir, 'cli-log')
if os.name == 'nt':
sockfile = '\\\\.\\pipe\\watchman-test-%s' % uuid.uuid4().hex
else:
sockfile = os.path.join(basedir, 'sock')
pidfile = os.path.join(basedir, 'pid')
statefile = os.path.join(basedir, 'state')
argv = [
args.watchman,
'--sockname',
sockfile,
'--logfile',
logfile,
'--pidfile',
pidfile,
'--statefile',
statefile,
'--foreground',
'--log-level=2', # debug logging for watchman
]
envb = osenvironb.copy()
envb[b'WATCHMAN_CONFIG_FILE'] = _sys2bytes(cfgfile)
with open(clilogfile, 'wb') as f:
proc = subprocess.Popen(
argv, env=envb, stdin=None, stdout=f, stderr=f
)
try:
yield sockfile
finally:
proc.terminate()
proc.kill()
finally:
if args.keep_fsmonitor_tmpdir:
print('fsmonitor dir available at %s' % basedir)
else:
shutil.rmtree(basedir, ignore_errors=True)
def run():
parser = getparser()
args, runtestsargv = parser.parse_known_args()
with watchman(args) as sockfile:
osenvironb[b'WATCHMAN_SOCK'] = _sys2bytes(sockfile)
# Indicate to hghave that we're running with fsmonitor enabled.
osenvironb[b'HGFSMONITOR_TESTS'] = b'1'
runtestdir = os.path.dirname(__file__)
runtests = os.path.join(runtestdir, 'run-tests.py')
blacklist = os.path.join(runtestdir, 'blacklists', 'fsmonitor')
runtestsargv.insert(0, runtests)
runtestsargv.extend(
[
'--extra-config',
'extensions.fsmonitor=',
# specify fsmonitor.mode=paranoid always in order to force
# fsmonitor extension execute "paranoid" code path
#
# TODO: make fsmonitor-run-tests.py accept specific options
'--extra-config',
'fsmonitor.mode=paranoid',
'--blacklist',
blacklist,
]
)
return subprocess.call(runtestsargv)
if __name__ == '__main__':
sys.exit(run())