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#
# Unit tests for the multiprocessing package
#
import unittest
import unittest.mock
import queue as pyqueue
import textwrap
import time
import io
import itertools
import sys
import os
import gc
import importlib
import errno
import functools
import signal
import array
import collections.abc
import socket
import random
import logging
import shutil
import subprocess
import struct
import tempfile
import operator
import pickle
import weakref
import warnings
import test.support
import test.support.script_helper
from test import support
from test.support import hashlib_helper
from test.support import import_helper
from test.support import os_helper
from test.support import script_helper
from test.support import socket_helper
from test.support import threading_helper
from test.support import warnings_helper
from test.support import subTests
from test.support.script_helper import assert_python_failure, assert_python_ok
# Skip tests if _multiprocessing wasn't built.
_multiprocessing = import_helper.import_module('_multiprocessing')
# Skip tests if sem_open implementation is broken.
support.skip_if_broken_multiprocessing_synchronize()
import threading
import multiprocessing.connection
import multiprocessing.dummy
import multiprocessing.heap
import multiprocessing.managers
import multiprocessing.pool
import multiprocessing.queues
from multiprocessing.connection import wait
from multiprocessing import util
try:
from multiprocessing import reduction
HAS_REDUCTION = reduction.HAVE_SEND_HANDLE
except ImportError:
HAS_REDUCTION = False
try:
from multiprocessing.sharedctypes import Value, copy
HAS_SHAREDCTYPES = True
except ImportError:
HAS_SHAREDCTYPES = False
try:
from multiprocessing import shared_memory
HAS_SHMEM = True
except ImportError:
HAS_SHMEM = False
try:
import msvcrt
except ImportError:
msvcrt = None
if support.HAVE_ASAN_FORK_BUG:
# gh-89363: Skip multiprocessing tests if Python is built with ASAN to
# work around a libasan race condition: dead lock in pthread_create().
raise unittest.SkipTest("libasan has a pthread_create() dead lock related to thread+fork")
# gh-110666: Tolerate a difference of 100 ms when comparing timings
# (clock resolution)
CLOCK_RES = 0.100
def latin(s):
return s.encode('latin')
def close_queue(queue):
if isinstance(queue, multiprocessing.queues.Queue):
queue.close()
queue.join_thread()
def join_process(process):
# Since multiprocessing.Process has the same API than threading.Thread
# (join() and is_alive(), the support function can be reused
threading_helper.join_thread(process)
if os.name == "posix":
from multiprocessing import resource_tracker
def _resource_unlink(name, rtype):
resource_tracker._CLEANUP_FUNCS[rtype](name)
#
# Constants
#
LOG_LEVEL = util.SUBWARNING
#LOG_LEVEL = logging.DEBUG
DELTA = 0.1
CHECK_TIMINGS = False # making true makes tests take a lot longer
# and can sometimes cause some non-serious
# failures because some calls block a bit
# longer than expected
if CHECK_TIMINGS:
TIMEOUT1, TIMEOUT2, TIMEOUT3 = 0.82, 0.35, 1.4
else:
TIMEOUT1, TIMEOUT2, TIMEOUT3 = 0.1, 0.1, 0.1
# BaseManager.shutdown_timeout
SHUTDOWN_TIMEOUT = support.SHORT_TIMEOUT
WAIT_ACTIVE_CHILDREN_TIMEOUT = 5.0
HAVE_GETVALUE = not getattr(_multiprocessing,
'HAVE_BROKEN_SEM_GETVALUE', False)
WIN32 = (sys.platform == "win32")
def wait_for_handle(handle, timeout):
if timeout is not None and timeout < 0.0:
timeout = None
return wait([handle], timeout)
try:
MAXFD = os.sysconf("SC_OPEN_MAX")
except:
MAXFD = 256
# To speed up tests when using the forkserver, we can preload these:
PRELOAD = ['__main__', 'test.test_multiprocessing_forkserver']
#
# Some tests require ctypes
#
try:
from ctypes import Structure, c_int, c_double, c_longlong
except ImportError:
Structure = object
c_int = c_double = c_longlong = None
def check_enough_semaphores():
"""Check that the system supports enough semaphores to run the test."""
# minimum number of semaphores available according to POSIX
nsems_min = 256
try:
nsems = os.sysconf("SC_SEM_NSEMS_MAX")
except (AttributeError, ValueError):
# sysconf not available or setting not available
return
if nsems == -1 or nsems >= nsems_min:
return
raise unittest.SkipTest("The OS doesn't support enough semaphores "
"to run the test (required: %d)." % nsems_min)
def only_run_in_spawn_testsuite(reason):
"""Returns a decorator: raises SkipTest when SM != spawn at test time.
This can be useful to save overall Python test suite execution time.
"spawn" is the universal mode available on all platforms so this limits the
decorated test to only execute within test_multiprocessing_spawn.
This would not be necessary if we refactored our test suite to split things
into other test files when they are not start method specific to be rerun
under all start methods.
"""
def decorator(test_item):
@functools.wraps(test_item)
def spawn_check_wrapper(*args, **kwargs):
if (start_method := multiprocessing.get_start_method()) != "spawn":
raise unittest.SkipTest(f"{start_method=}, not 'spawn'; {reason}")
return test_item(*args, **kwargs)
return spawn_check_wrapper
return decorator
class TestInternalDecorators(unittest.TestCase):
"""Logic within a test suite that could errantly skip tests? Test it!"""
@unittest.skipIf(sys.platform == "win32", "test requires that fork exists.")
def test_only_run_in_spawn_testsuite(self):
if multiprocessing.get_start_method() != "spawn":
raise unittest.SkipTest("only run in test_multiprocessing_spawn.")
try:
@only_run_in_spawn_testsuite("testing this decorator")
def return_four_if_spawn():
return 4
except Exception as err:
self.fail(f"expected decorated `def` not to raise; caught {err}")
orig_start_method = multiprocessing.get_start_method(allow_none=True)
try:
multiprocessing.set_start_method("spawn", force=True)
self.assertEqual(return_four_if_spawn(), 4)
multiprocessing.set_start_method("fork", force=True)
with self.assertRaises(unittest.SkipTest) as ctx:
return_four_if_spawn()
self.assertIn("testing this decorator", str(ctx.exception))
self.assertIn("start_method=", str(ctx.exception))
finally:
multiprocessing.set_start_method(orig_start_method, force=True)
#
# Creates a wrapper for a function which records the time it takes to finish
#
class TimingWrapper(object):
def __init__(self, func):
self.func = func
self.elapsed = None
def __call__(self, *args, **kwds):
t = time.monotonic()
try:
return self.func(*args, **kwds)
finally:
self.elapsed = time.monotonic() - t
#
# Base class for test cases
#
class BaseTestCase(object):
ALLOWED_TYPES = ('processes', 'manager', 'threads')
# If not empty, limit which start method suites run this class.
START_METHODS: set[str] = set()
start_method = None # set by install_tests_in_module_dict()
def assertTimingAlmostEqual(self, a, b):
if CHECK_TIMINGS:
self.assertAlmostEqual(a, b, 1)
def assertReturnsIfImplemented(self, value, func, *args):
try:
res = func(*args)
except NotImplementedError:
pass
else:
return self.assertEqual(value, res)
# For the sanity of Windows users, rather than crashing or freezing in
# multiple ways.
def __reduce__(self, *args):
raise NotImplementedError("shouldn't try to pickle a test case")
__reduce_ex__ = __reduce__
#
# Return the value of a semaphore
#
def get_value(self):
try:
return self.get_value()
except AttributeError:
try:
return self._Semaphore__value
except AttributeError:
try:
return self._value
except AttributeError:
raise NotImplementedError
#
# Testcases
#
class DummyCallable:
def __call__(self, q, c):
assert isinstance(c, DummyCallable)
q.put(5)
class _TestProcess(BaseTestCase):
ALLOWED_TYPES = ('processes', 'threads')
def test_current(self):
if self.TYPE == 'threads':
self.skipTest('test not appropriate for {}'.format(self.TYPE))
current = self.current_process()
authkey = current.authkey
self.assertTrue(current.is_alive())
self.assertFalse(current.daemon)
self.assertIsInstance(authkey, bytes)
self.assertTrue(len(authkey) > 0)
self.assertEqual(current.ident, os.getpid())
self.assertEqual(current.exitcode, None)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_set_executable(self):
if self.TYPE == 'threads':
self.skipTest(f'test not appropriate for {self.TYPE}')
paths = [
sys.executable, # str
os.fsencode(sys.executable), # bytes
os_helper.FakePath(sys.executable), # os.PathLike
os_helper.FakePath(os.fsencode(sys.executable)), # os.PathLike bytes
]
for path in paths:
self.set_executable(path)
p = self.Process()
p.start()
p.join()
self.assertEqual(p.exitcode, 0)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
@support.requires_resource('cpu')
def test_args_argument(self):
# bpo-45735: Using list or tuple as *args* in constructor could
# achieve the same effect.
args_cases = (1, "str", [1], (1,))
args_types = (list, tuple)
test_cases = itertools.product(args_cases, args_types)
for args, args_type in test_cases:
with self.subTest(args=args, args_type=args_type):
q = self.Queue(1)
# pass a tuple or list as args
p = self.Process(target=self._test_args, args=args_type((q, args)))
p.daemon = True
p.start()
child_args = q.get()
self.assertEqual(child_args, args)
p.join()
close_queue(q)
@classmethod
def _test_args(cls, q, arg):
q.put(arg)
def test_daemon_argument(self):
if self.TYPE == "threads":
self.skipTest('test not appropriate for {}'.format(self.TYPE))
# By default uses the current process's daemon flag.
proc0 = self.Process(target=self._test)
self.assertEqual(proc0.daemon, self.current_process().daemon)
proc1 = self.Process(target=self._test, daemon=True)
self.assertTrue(proc1.daemon)
proc2 = self.Process(target=self._test, daemon=False)
self.assertFalse(proc2.daemon)
@classmethod
def _test(cls, q, *args, **kwds):
current = cls.current_process()
q.put(args)
q.put(kwds)
q.put(current.name)
if cls.TYPE != 'threads':
q.put(bytes(current.authkey))
q.put(current.pid)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_parent_process_attributes(self):
if self.TYPE == "threads":
self.skipTest('test not appropriate for {}'.format(self.TYPE))
self.assertIsNone(self.parent_process())
rconn, wconn = self.Pipe(duplex=False)
p = self.Process(target=self._test_send_parent_process, args=(wconn,))
p.start()
p.join()
parent_pid, parent_name = rconn.recv()
self.assertEqual(parent_pid, self.current_process().pid)
self.assertEqual(parent_pid, os.getpid())
self.assertEqual(parent_name, self.current_process().name)
@classmethod
def _test_send_parent_process(cls, wconn):
from multiprocessing.process import parent_process
wconn.send([parent_process().pid, parent_process().name])
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_parent_process(self):
if self.TYPE == "threads":
self.skipTest('test not appropriate for {}'.format(self.TYPE))
# Launch a child process. Make it launch a grandchild process. Kill the
# child process and make sure that the grandchild notices the death of
# its parent (a.k.a the child process).
rconn, wconn = self.Pipe(duplex=False)
p = self.Process(
target=self._test_create_grandchild_process, args=(wconn, ))
p.start()
if not rconn.poll(timeout=support.LONG_TIMEOUT):
raise AssertionError("Could not communicate with child process")
parent_process_status = rconn.recv()
self.assertEqual(parent_process_status, "alive")
p.terminate()
p.join()
if not rconn.poll(timeout=support.LONG_TIMEOUT):
raise AssertionError("Could not communicate with child process")
parent_process_status = rconn.recv()
self.assertEqual(parent_process_status, "not alive")
@classmethod
def _test_create_grandchild_process(cls, wconn):
p = cls.Process(target=cls._test_report_parent_status, args=(wconn, ))
p.start()
time.sleep(300)
@classmethod
def _test_report_parent_status(cls, wconn):
from multiprocessing.process import parent_process
wconn.send("alive" if parent_process().is_alive() else "not alive")
parent_process().join(timeout=support.SHORT_TIMEOUT)
wconn.send("alive" if parent_process().is_alive() else "not alive")
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_process(self):
q = self.Queue(1)
e = self.Event()
args = (q, 1, 2)
kwargs = {'hello':23, 'bye':2.54}
name = 'SomeProcess'
p = self.Process(
target=self._test, args=args, kwargs=kwargs, name=name
)
p.daemon = True
current = self.current_process()
if self.TYPE != 'threads':
self.assertEqual(p.authkey, current.authkey)
self.assertEqual(p.is_alive(), False)
self.assertEqual(p.daemon, True)
self.assertNotIn(p, self.active_children())
self.assertIs(type(self.active_children()), list)
self.assertEqual(p.exitcode, None)
p.start()
self.assertEqual(p.exitcode, None)
self.assertEqual(p.is_alive(), True)
self.assertIn(p, self.active_children())
self.assertEqual(q.get(), args[1:])
self.assertEqual(q.get(), kwargs)
self.assertEqual(q.get(), p.name)
if self.TYPE != 'threads':
self.assertEqual(q.get(), current.authkey)
self.assertEqual(q.get(), p.pid)
p.join()
self.assertEqual(p.exitcode, 0)
self.assertEqual(p.is_alive(), False)
self.assertNotIn(p, self.active_children())
close_queue(q)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
@unittest.skipUnless(threading._HAVE_THREAD_NATIVE_ID, "needs native_id")
def test_process_mainthread_native_id(self):
if self.TYPE == 'threads':
self.skipTest('test not appropriate for {}'.format(self.TYPE))
current_mainthread_native_id = threading.main_thread().native_id
q = self.Queue(1)
p = self.Process(target=self._test_process_mainthread_native_id, args=(q,))
p.start()
child_mainthread_native_id = q.get()
p.join()
close_queue(q)
self.assertNotEqual(current_mainthread_native_id, child_mainthread_native_id)
@classmethod
def _test_process_mainthread_native_id(cls, q):
mainthread_native_id = threading.main_thread().native_id
q.put(mainthread_native_id)
@classmethod
def _sleep_some(cls):
time.sleep(100)
@classmethod
def _sleep_some_event(cls, event):
event.set()
time.sleep(100)
@classmethod
def _sleep_no_int_handler(cls, event):
signal.signal(signal.SIGINT, signal.SIG_DFL)
cls._sleep_some_event(event)
@classmethod
def _test_sleep(cls, delay):
time.sleep(delay)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def _kill_process(self, meth, target=None):
if self.TYPE == 'threads':
self.skipTest('test not appropriate for {}'.format(self.TYPE))
event = self.Event()
if not target:
target = self._sleep_some_event
p = self.Process(target=target, args=(event,))
p.daemon = True
p.start()
self.assertEqual(p.is_alive(), True)
self.assertIn(p, self.active_children())
self.assertEqual(p.exitcode, None)
join = TimingWrapper(p.join)
self.assertEqual(join(0), None)
self.assertTimingAlmostEqual(join.elapsed, 0.0)
self.assertEqual(p.is_alive(), True)
self.assertEqual(join(-1), None)
self.assertTimingAlmostEqual(join.elapsed, 0.0)
self.assertEqual(p.is_alive(), True)
timeout = support.SHORT_TIMEOUT
if not event.wait(timeout):
p.terminate()
p.join()
self.fail(f"event not signaled in {timeout} seconds")
meth(p)
if hasattr(signal, 'alarm'):
# On the Gentoo buildbot waitpid() often seems to block forever.
# We use alarm() to interrupt it if it blocks for too long.
def handler(*args):
raise RuntimeError('join took too long: %s' % p)
old_handler = signal.signal(signal.SIGALRM, handler)
try:
signal.alarm(10)
self.assertEqual(join(), None)
finally:
signal.alarm(0)
signal.signal(signal.SIGALRM, old_handler)
else:
self.assertEqual(join(), None)
self.assertTimingAlmostEqual(join.elapsed, 0.0)
self.assertEqual(p.is_alive(), False)
self.assertNotIn(p, self.active_children())
p.join()
return p.exitcode
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
@unittest.skipIf(os.name == 'nt', "POSIX only")
def test_interrupt(self):
exitcode = self._kill_process(multiprocessing.Process.interrupt)
self.assertEqual(exitcode, 1)
# exit code 1 is hard-coded for uncaught exceptions
# (KeyboardInterrupt in this case)
# in multiprocessing.BaseProcess._bootstrap
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
@unittest.skipIf(os.name == 'nt', "POSIX only")
def test_interrupt_no_handler(self):
exitcode = self._kill_process(multiprocessing.Process.interrupt, target=self._sleep_no_int_handler)
self.assertEqual(exitcode, -signal.SIGINT)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_terminate(self):
exitcode = self._kill_process(multiprocessing.Process.terminate)
self.assertEqual(exitcode, -signal.SIGTERM)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_kill(self):
exitcode = self._kill_process(multiprocessing.Process.kill)
if os.name != 'nt':
self.assertEqual(exitcode, -signal.SIGKILL)
else:
self.assertEqual(exitcode, -signal.SIGTERM)
def test_cpu_count(self):
try:
cpus = multiprocessing.cpu_count()
except NotImplementedError:
cpus = 1
self.assertIsInstance(cpus, int)
self.assertGreaterEqual(cpus, 1)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_active_children(self):
self.assertEqual(type(self.active_children()), list)
event = self.Event()
p = self.Process(target=event.wait, args=())
self.assertNotIn(p, self.active_children())
try:
p.daemon = True
p.start()
self.assertIn(p, self.active_children())
finally:
event.set()
p.join()
self.assertNotIn(p, self.active_children())
@classmethod
def _test_recursion(cls, wconn, id):
wconn.send(id)
if len(id) < 2:
for i in range(2):
p = cls.Process(
target=cls._test_recursion, args=(wconn, id+[i])
)
p.start()
p.join()
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_recursion(self):
rconn, wconn = self.Pipe(duplex=False)
self._test_recursion(wconn, [])
time.sleep(DELTA)
result = []
while rconn.poll():
result.append(rconn.recv())
expected = [
[],
[0],
[0, 0],
[0, 1],
[1],
[1, 0],
[1, 1]
]
self.assertEqual(result, expected)
@classmethod
def _test_sentinel(cls, event):
event.wait(10.0)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_sentinel(self):
if self.TYPE == "threads":
self.skipTest('test not appropriate for {}'.format(self.TYPE))
event = self.Event()
p = self.Process(target=self._test_sentinel, args=(event,))
with self.assertRaises(ValueError):
p.sentinel
p.start()
self.addCleanup(p.join)
sentinel = p.sentinel
self.assertIsInstance(sentinel, int)
self.assertFalse(wait_for_handle(sentinel, timeout=0.0))
event.set()
p.join()
self.assertTrue(wait_for_handle(sentinel, timeout=1))
@classmethod
def _test_close(cls, rc=0, q=None):
if q is not None:
q.get()
sys.exit(rc)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_close(self):
if self.TYPE == "threads":
self.skipTest('test not appropriate for {}'.format(self.TYPE))
q = self.Queue()
p = self.Process(target=self._test_close, kwargs={'q': q})
p.daemon = True
p.start()
self.assertEqual(p.is_alive(), True)
# Child is still alive, cannot close
with self.assertRaises(ValueError):
p.close()
q.put(None)
p.join()
self.assertEqual(p.is_alive(), False)
self.assertEqual(p.exitcode, 0)
p.close()
with self.assertRaises(ValueError):
p.is_alive()
with self.assertRaises(ValueError):
p.join()
with self.assertRaises(ValueError):
p.terminate()
p.close()
wr = weakref.ref(p)
del p
gc.collect()
self.assertIs(wr(), None)
close_queue(q)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
@support.requires_resource('walltime')
def test_many_processes(self):
if self.TYPE == 'threads':
self.skipTest('test not appropriate for {}'.format(self.TYPE))
sm = multiprocessing.get_start_method()
N = 5 if sm == 'spawn' else 100
# Try to overwhelm the forkserver loop with events
procs = [self.Process(target=self._test_sleep, args=(0.01,))
for i in range(N)]
for p in procs:
p.start()
for p in procs:
join_process(p)
for p in procs:
self.assertEqual(p.exitcode, 0)
procs = [self.Process(target=self._sleep_some)
for i in range(N)]
for p in procs:
p.start()
time.sleep(0.001) # let the children start...
for p in procs:
p.terminate()
for p in procs:
join_process(p)
if os.name != 'nt':
exitcodes = [-signal.SIGTERM]
if sys.platform == 'darwin':
# bpo-31510: On macOS, killing a freshly started process with
# SIGTERM sometimes kills the process with SIGKILL.
exitcodes.append(-signal.SIGKILL)
for p in procs:
self.assertIn(p.exitcode, exitcodes)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_lose_target_ref(self):
c = DummyCallable()
wr = weakref.ref(c)
q = self.Queue()
p = self.Process(target=c, args=(q, c))
del c
p.start()
p.join()
gc.collect() # For PyPy or other GCs.
self.assertIs(wr(), None)
self.assertEqual(q.get(), 5)
close_queue(q)
@classmethod
def _test_child_fd_inflation(self, evt, q):
q.put(os_helper.fd_count())
evt.wait()
def test_child_fd_inflation(self):
# Number of fds in child processes should not grow with the
# number of running children.
if self.TYPE == 'threads':
self.skipTest('test not appropriate for {}'.format(self.TYPE))
sm = multiprocessing.get_start_method()
if sm == 'fork':
# The fork method by design inherits all fds from the parent,
# trying to go against it is a lost battle
self.skipTest('test not appropriate for {}'.format(sm))
N = 5
evt = self.Event()
q = self.Queue()
procs = [self.Process(target=self._test_child_fd_inflation, args=(evt, q))
for i in range(N)]
for p in procs:
p.start()
try:
fd_counts = [q.get() for i in range(N)]
self.assertEqual(len(set(fd_counts)), 1, fd_counts)
finally:
evt.set()
for p in procs:
p.join()
close_queue(q)
@classmethod
def _test_wait_for_threads(self, evt):
def func1():
time.sleep(0.5)
evt.set()
def func2():
time.sleep(20)
evt.clear()
threading.Thread(target=func1).start()
threading.Thread(target=func2, daemon=True).start()
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_wait_for_threads(self):
# A child process should wait for non-daemonic threads to end
# before exiting
if self.TYPE == 'threads':
self.skipTest('test not appropriate for {}'.format(self.TYPE))
evt = self.Event()
proc = self.Process(target=self._test_wait_for_threads, args=(evt,))
proc.start()
proc.join()
self.assertTrue(evt.is_set())
@classmethod
def _test_error_on_stdio_flush(self, evt, break_std_streams={}):
for stream_name, action in break_std_streams.items():
if action == 'close':
stream = io.StringIO()
stream.close()
else:
assert action == 'remove'
stream = None
setattr(sys, stream_name, None)
evt.set()
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_error_on_stdio_flush_1(self):
# Check that Process works with broken standard streams
streams = [io.StringIO(), None]
streams[0].close()
for stream_name in ('stdout', 'stderr'):
for stream in streams:
old_stream = getattr(sys, stream_name)
setattr(sys, stream_name, stream)
try:
evt = self.Event()
proc = self.Process(target=self._test_error_on_stdio_flush,
args=(evt,))
proc.start()
proc.join()
self.assertTrue(evt.is_set())
self.assertEqual(proc.exitcode, 0)
finally:
setattr(sys, stream_name, old_stream)
@warnings_helper.ignore_fork_in_thread_deprecation_warnings()
def test_error_on_stdio_flush_2(self):
# Same as test_error_on_stdio_flush_1(), but standard streams are
# broken by the child process
for stream_name in ('stdout', 'stderr'):
for action in ('close', 'remove'):
old_stream = getattr(sys, stream_name)
try:
evt = self.Event()
proc = self.Process(target=self._test_error_on_stdio_flush,
args=(evt, {stream_name: action}))
proc.start()
proc.join()
self.assertTrue(evt.is_set())
self.assertEqual(proc.exitcode, 0)
finally:
setattr(sys, stream_name, old_stream)
@staticmethod
def _sleep_and_set_event(evt, delay=0.0):
time.sleep(delay)
evt.set()
def check_forkserver_death(self, signum):
# bpo-31308: if the forkserver process has died, we should still
# be able to create and run new Process instances (the forkserver
# is implicitly restarted).
if self.TYPE == 'threads':
self.skipTest('test not appropriate for {}'.format(self.TYPE))
sm = multiprocessing.get_start_method()
if sm != 'forkserver':
# The fork method by design inherits all fds from the parent,
# trying to go against it is a lost battle
self.skipTest('test not appropriate for {}'.format(sm))
from multiprocessing.forkserver import _forkserver
_forkserver.ensure_running()
# First process sleeps 500 ms
delay = 0.5
evt = self.Event()
proc = self.Process(target=self._sleep_and_set_event, args=(evt, delay))
proc.start()
pid = _forkserver._forkserver_pid
os.kill(pid, signum)
# give time to the fork server to die and time to proc to complete
time.sleep(delay * 2.0)
evt2 = self.Event()
proc2 = self.Process(target=self._sleep_and_set_event, args=(evt2,))
proc2.start()
proc2.join()
self.assertTrue(evt2.is_set())
self.assertEqual(proc2.exitcode, 0)
proc.join()
self.assertTrue(evt.is_set())
self.assertIn(proc.exitcode, (0, 255))
def test_forkserver_sigint(self):
# Catchable signal
self.check_forkserver_death(signal.SIGINT)
def test_forkserver_sigkill(self):
# Uncatchable signal
if os.name != 'nt':
self.check_forkserver_death(signal.SIGKILL)
def test_forkserver_auth_is_enabled(self):
if self.TYPE == "threads":
self.skipTest(f"test not appropriate for {self.TYPE}")
if multiprocessing.get_start_method() != "forkserver":
self.skipTest("forkserver start method specific")
forkserver = multiprocessing.forkserver._forkserver
forkserver.ensure_running()
self.assertTrue(forkserver._forkserver_pid)
authkey = forkserver._forkserver_authkey
self.assertTrue(authkey)
self.assertGreater(len(authkey), 15)
addr = forkserver._forkserver_address
self.assertTrue(addr)
# Demonstrate that a raw auth handshake, as Client performs, does not
# raise an error.
client = multiprocessing.connection.Client(addr, authkey=authkey)
client.close()
# That worked, now launch a quick process.
proc = self.Process(target=sys.exit)
proc.start()
proc.join()
self.assertEqual(proc.exitcode, 0)
def test_forkserver_without_auth_fails(self):
if self.TYPE == "threads":
self.skipTest(f"test not appropriate for {self.TYPE}")
if multiprocessing.get_start_method() != "forkserver":
self.skipTest("forkserver start method specific")
forkserver = multiprocessing.forkserver._forkserver
forkserver.ensure_running()
self.assertTrue(forkserver._forkserver_pid)
authkey_len = len(forkserver._forkserver_authkey)
with unittest.mock.patch.object(
forkserver, '_forkserver_authkey', None):
# With an incorrect authkey we should get an auth rejection
# rather than the above protocol error.
forkserver._forkserver_authkey = b'T' * authkey_len
proc = self.Process(target=sys.exit)
with self.assertRaises(multiprocessing.AuthenticationError):
proc.start()
del proc