dirstate: issue a developer warning on implicit write on wlock release
Our goal is to get rid of all these to clarify the writing pattern, so it is
time to warn about this (and later, forbid it).
#!/usr/bin/env python
"""
Tests the buffering behavior of stdio streams in `mercurial.utils.procutil`.
"""
import contextlib
import errno
import os
import pickle
import signal
import subprocess
import sys
import tempfile
import unittest
from mercurial import pycompat, util
TEST_BUFFERING_CHILD_SCRIPT = r'''
import os
from mercurial import dispatch
from mercurial.utils import procutil
dispatch.initstdio()
procutil.{stream}.write(b'aaa')
os.write(procutil.{stream}.fileno(), b'[written aaa]')
procutil.{stream}.write(b'bbb\n')
os.write(procutil.{stream}.fileno(), b'[written bbb\\n]')
'''
UNBUFFERED = b'aaa[written aaa]bbb\n[written bbb\\n]'
LINE_BUFFERED = b'[written aaa]aaabbb\n[written bbb\\n]'
FULLY_BUFFERED = b'[written aaa][written bbb\\n]aaabbb\n'
TEST_LARGE_WRITE_CHILD_SCRIPT = r'''
import os
import signal
import sys
from mercurial import dispatch
from mercurial.utils import procutil
signal.signal(signal.SIGINT, lambda *x: None)
dispatch.initstdio()
write_result = procutil.{stream}.write(b'x' * 1048576)
with os.fdopen(
os.open({write_result_fn!r}, os.O_WRONLY | getattr(os, 'O_TEMPORARY', 0)),
'w',
) as write_result_f:
write_result_f.write(str(write_result))
'''
TEST_BROKEN_PIPE_CHILD_SCRIPT = r'''
import os
import pickle
from mercurial import dispatch
from mercurial.utils import procutil
dispatch.initstdio()
procutil.stdin.read(1) # wait until parent process closed pipe
try:
procutil.{stream}.write(b'test')
procutil.{stream}.flush()
except EnvironmentError as e:
with os.fdopen(
os.open(
{err_fn!r},
os.O_WRONLY
| getattr(os, 'O_BINARY', 0)
| getattr(os, 'O_TEMPORARY', 0),
),
'wb',
) as err_f:
pickle.dump(e, err_f)
# Exit early to suppress further broken pipe errors at interpreter shutdown.
os._exit(0)
'''
@contextlib.contextmanager
def _closing(fds):
try:
yield
finally:
for fd in fds:
try:
os.close(fd)
except EnvironmentError:
pass
# In the following, we set the FDs non-inheritable mainly to make it possible
# for tests to close the receiving end of the pipe / PTYs.
@contextlib.contextmanager
def _devnull():
devnull = os.open(os.devnull, os.O_WRONLY)
# We don't have a receiving end, so it's not worth the effort on Python 2
# on Windows to make the FD non-inheritable.
with _closing([devnull]):
yield (None, devnull)
@contextlib.contextmanager
def _pipes():
rwpair = os.pipe()
with _closing(rwpair):
yield rwpair
@contextlib.contextmanager
def _ptys():
if pycompat.iswindows:
raise unittest.SkipTest("PTYs are not supported on Windows")
import pty
import tty
rwpair = pty.openpty()
with _closing(rwpair):
tty.setraw(rwpair[0])
yield rwpair
def _readall(fd, buffer_size, initial_buf=None):
buf = initial_buf or []
while True:
try:
s = os.read(fd, buffer_size)
except OSError as e:
if e.errno == errno.EIO:
# If the child-facing PTY got closed, reading from the
# parent-facing PTY raises EIO.
break
raise
if not s:
break
buf.append(s)
return b''.join(buf)
class TestStdio(unittest.TestCase):
def _test(
self,
child_script,
stream,
rwpair_generator,
check_output,
python_args=[],
post_child_check=None,
stdin_generator=None,
):
assert stream in ('stdout', 'stderr')
if stdin_generator is None:
stdin_generator = open(os.devnull, 'rb')
with rwpair_generator() as (
stream_receiver,
child_stream,
), stdin_generator as child_stdin:
proc = subprocess.Popen(
[sys.executable] + python_args + ['-c', child_script],
stdin=child_stdin,
stdout=child_stream if stream == 'stdout' else None,
stderr=child_stream if stream == 'stderr' else None,
)
try:
os.close(child_stream)
if stream_receiver is not None:
check_output(stream_receiver, proc)
except: # re-raises
proc.terminate()
raise
finally:
retcode = proc.wait()
self.assertEqual(retcode, 0)
if post_child_check is not None:
post_child_check()
def _test_buffering(
self, stream, rwpair_generator, expected_output, python_args=[]
):
def check_output(stream_receiver, proc):
self.assertEqual(_readall(stream_receiver, 1024), expected_output)
self._test(
TEST_BUFFERING_CHILD_SCRIPT.format(stream=stream),
stream,
rwpair_generator,
check_output,
python_args,
)
def test_buffering_stdout_devnull(self):
self._test_buffering('stdout', _devnull, None)
def test_buffering_stdout_pipes(self):
self._test_buffering('stdout', _pipes, FULLY_BUFFERED)
def test_buffering_stdout_ptys(self):
self._test_buffering('stdout', _ptys, LINE_BUFFERED)
def test_buffering_stdout_devnull_unbuffered(self):
self._test_buffering('stdout', _devnull, None, python_args=['-u'])
def test_buffering_stdout_pipes_unbuffered(self):
self._test_buffering('stdout', _pipes, UNBUFFERED, python_args=['-u'])
def test_buffering_stdout_ptys_unbuffered(self):
self._test_buffering('stdout', _ptys, UNBUFFERED, python_args=['-u'])
def _test_large_write(self, stream, rwpair_generator, python_args=[]):
def check_output(stream_receiver, proc):
if not pycompat.iswindows:
# On Unix, we can provoke a partial write() by interrupting it
# by a signal handler as soon as a bit of data was written.
# We test that write() is called until all data is written.
buf = [os.read(stream_receiver, 1)]
proc.send_signal(signal.SIGINT)
else:
# On Windows, there doesn't seem to be a way to cause partial
# writes.
buf = []
self.assertEqual(
_readall(stream_receiver, 131072, buf), b'x' * 1048576
)
def post_child_check():
self.assertEqual(write_result_f.read(), '1048576')
with tempfile.NamedTemporaryFile('r') as write_result_f:
self._test(
TEST_LARGE_WRITE_CHILD_SCRIPT.format(
stream=stream, write_result_fn=write_result_f.name
),
stream,
rwpair_generator,
check_output,
python_args,
post_child_check=post_child_check,
)
def test_large_write_stdout_devnull(self):
self._test_large_write('stdout', _devnull)
def test_large_write_stdout_pipes(self):
self._test_large_write('stdout', _pipes)
def test_large_write_stdout_ptys(self):
self._test_large_write('stdout', _ptys)
def test_large_write_stdout_devnull_unbuffered(self):
self._test_large_write('stdout', _devnull, python_args=['-u'])
def test_large_write_stdout_pipes_unbuffered(self):
self._test_large_write('stdout', _pipes, python_args=['-u'])
def test_large_write_stdout_ptys_unbuffered(self):
self._test_large_write('stdout', _ptys, python_args=['-u'])
def test_large_write_stderr_devnull(self):
self._test_large_write('stderr', _devnull)
def test_large_write_stderr_pipes(self):
self._test_large_write('stderr', _pipes)
def test_large_write_stderr_ptys(self):
self._test_large_write('stderr', _ptys)
def test_large_write_stderr_devnull_unbuffered(self):
self._test_large_write('stderr', _devnull, python_args=['-u'])
def test_large_write_stderr_pipes_unbuffered(self):
self._test_large_write('stderr', _pipes, python_args=['-u'])
def test_large_write_stderr_ptys_unbuffered(self):
self._test_large_write('stderr', _ptys, python_args=['-u'])
def _test_broken_pipe(self, stream):
assert stream in ('stdout', 'stderr')
def check_output(stream_receiver, proc):
os.close(stream_receiver)
proc.stdin.write(b'x')
proc.stdin.close()
def post_child_check():
err = pickle.load(err_f)
self.assertEqual(err.errno, errno.EPIPE)
self.assertEqual(err.strerror, "Broken pipe")
with tempfile.NamedTemporaryFile('rb') as err_f:
self._test(
TEST_BROKEN_PIPE_CHILD_SCRIPT.format(
stream=stream, err_fn=err_f.name
),
stream,
_pipes,
check_output,
post_child_check=post_child_check,
stdin_generator=util.nullcontextmanager(subprocess.PIPE),
)
def test_broken_pipe_stdout(self):
self._test_broken_pipe('stdout')
def test_broken_pipe_stderr(self):
self._test_broken_pipe('stderr')
if __name__ == '__main__':
import silenttestrunner
silenttestrunner.main(__name__)