Mini Shell
"""
Tests for the threading module.
"""
import test.support
from test.support import (verbose, import_module, cpython_only,
requires_type_collecting)
from test.support.script_helper import assert_python_ok, assert_python_failure
import random
import sys
import _thread
import threading
import time
import unittest
import weakref
import os
import subprocess
import signal
from test import lock_tests
from test import support
# Between fork() and exec(), only async-safe functions are allowed (issues
# #12316 and #11870), and fork() from a worker thread is known to trigger
# problems with some operating systems (issue #3863): skip problematic tests
# on platforms known to behave badly.
platforms_to_skip = ('netbsd5', 'hp-ux11')
# A trivial mutable counter.
class Counter(object):
def __init__(self):
self.value = 0
def inc(self):
self.value += 1
def dec(self):
self.value -= 1
def get(self):
return self.value
class TestThread(threading.Thread):
def __init__(self, name, testcase, sema, mutex, nrunning):
threading.Thread.__init__(self, name=name)
self.testcase = testcase
self.sema = sema
self.mutex = mutex
self.nrunning = nrunning
def run(self):
delay = random.random() / 10000.0
if verbose:
print('task %s will run for %.1f usec' %
(self.name, delay * 1e6))
with self.sema:
with self.mutex:
self.nrunning.inc()
if verbose:
print(self.nrunning.get(), 'tasks are running')
self.testcase.assertLessEqual(self.nrunning.get(), 3)
time.sleep(delay)
if verbose:
print('task', self.name, 'done')
with self.mutex:
self.nrunning.dec()
self.testcase.assertGreaterEqual(self.nrunning.get(), 0)
if verbose:
print('%s is finished. %d tasks are running' %
(self.name, self.nrunning.get()))
class BaseTestCase(unittest.TestCase):
def setUp(self):
self._threads = test.support.threading_setup()
def tearDown(self):
test.support.threading_cleanup(*self._threads)
test.support.reap_children()
class ThreadTests(BaseTestCase):
# Create a bunch of threads, let each do some work, wait until all are
# done.
def test_various_ops(self):
# This takes about n/3 seconds to run (about n/3 clumps of tasks,
# times about 1 second per clump).
NUMTASKS = 10
# no more than 3 of the 10 can run at once
sema = threading.BoundedSemaphore(value=3)
mutex = threading.RLock()
numrunning = Counter()
threads = []
for i in range(NUMTASKS):
t = TestThread("<thread %d>"%i, self, sema, mutex, numrunning)
threads.append(t)
self.assertIsNone(t.ident)
self.assertRegex(repr(t), r'^<TestThread\(.*, initial\)>$')
t.start()
if hasattr(threading, 'get_native_id'):
native_ids = set(t.native_id for t in threads) | {threading.get_native_id()}
self.assertNotIn(None, native_ids)
self.assertEqual(len(native_ids), NUMTASKS + 1)
if verbose:
print('waiting for all tasks to complete')
for t in threads:
t.join()
self.assertFalse(t.is_alive())
self.assertNotEqual(t.ident, 0)
self.assertIsNotNone(t.ident)
self.assertRegex(repr(t), r'^<TestThread\(.*, stopped -?\d+\)>$')
if verbose:
print('all tasks done')
self.assertEqual(numrunning.get(), 0)
def test_ident_of_no_threading_threads(self):
# The ident still must work for the main thread and dummy threads.
self.assertIsNotNone(threading.currentThread().ident)
def f():
ident.append(threading.currentThread().ident)
done.set()
done = threading.Event()
ident = []
with support.wait_threads_exit():
tid = _thread.start_new_thread(f, ())
done.wait()
self.assertEqual(ident[0], tid)
# Kill the "immortal" _DummyThread
del threading._active[ident[0]]
# run with a small(ish) thread stack size (256 KiB)
def test_various_ops_small_stack(self):
if verbose:
print('with 256 KiB thread stack size...')
try:
threading.stack_size(262144)
except _thread.error:
raise unittest.SkipTest(
'platform does not support changing thread stack size')
self.test_various_ops()
threading.stack_size(0)
# run with a large thread stack size (1 MiB)
def test_various_ops_large_stack(self):
if verbose:
print('with 1 MiB thread stack size...')
try:
threading.stack_size(0x100000)
except _thread.error:
raise unittest.SkipTest(
'platform does not support changing thread stack size')
self.test_various_ops()
threading.stack_size(0)
def test_foreign_thread(self):
# Check that a "foreign" thread can use the threading module.
def f(mutex):
# Calling current_thread() forces an entry for the foreign
# thread to get made in the threading._active map.
threading.current_thread()
mutex.release()
mutex = threading.Lock()
mutex.acquire()
with support.wait_threads_exit():
tid = _thread.start_new_thread(f, (mutex,))
# Wait for the thread to finish.
mutex.acquire()
self.assertIn(tid, threading._active)
self.assertIsInstance(threading._active[tid], threading._DummyThread)
#Issue 29376
self.assertTrue(threading._active[tid].is_alive())
self.assertRegex(repr(threading._active[tid]), '_DummyThread')
del threading._active[tid]
# PyThreadState_SetAsyncExc() is a CPython-only gimmick, not (currently)
# exposed at the Python level. This test relies on ctypes to get at it.
def test_PyThreadState_SetAsyncExc(self):
ctypes = import_module("ctypes")
set_async_exc = ctypes.pythonapi.PyThreadState_SetAsyncExc
set_async_exc.argtypes = (ctypes.c_ulong, ctypes.py_object)
class AsyncExc(Exception):
pass
exception = ctypes.py_object(AsyncExc)
# First check it works when setting the exception from the same thread.
tid = threading.get_ident()
self.assertIsInstance(tid, int)
self.assertGreater(tid, 0)
try:
result = set_async_exc(tid, exception)
# The exception is async, so we might have to keep the VM busy until
# it notices.
while True:
pass
except AsyncExc:
pass
else:
# This code is unreachable but it reflects the intent. If we wanted
# to be smarter the above loop wouldn't be infinite.
self.fail("AsyncExc not raised")
try:
self.assertEqual(result, 1) # one thread state modified
except UnboundLocalError:
# The exception was raised too quickly for us to get the result.
pass
# `worker_started` is set by the thread when it's inside a try/except
# block waiting to catch the asynchronously set AsyncExc exception.
# `worker_saw_exception` is set by the thread upon catching that
# exception.
worker_started = threading.Event()
worker_saw_exception = threading.Event()
class Worker(threading.Thread):
def run(self):
self.id = threading.get_ident()
self.finished = False
try:
while True:
worker_started.set()
time.sleep(0.1)
except AsyncExc:
self.finished = True
worker_saw_exception.set()
t = Worker()
t.daemon = True # so if this fails, we don't hang Python at shutdown
t.start()
if verbose:
print(" started worker thread")
# Try a thread id that doesn't make sense.
if verbose:
print(" trying nonsensical thread id")
result = set_async_exc(-1, exception)
self.assertEqual(result, 0) # no thread states modified
# Now raise an exception in the worker thread.
if verbose:
print(" waiting for worker thread to get started")
ret = worker_started.wait()
self.assertTrue(ret)
if verbose:
print(" verifying worker hasn't exited")
self.assertFalse(t.finished)
if verbose:
print(" attempting to raise asynch exception in worker")
result = set_async_exc(t.id, exception)
self.assertEqual(result, 1) # one thread state modified
if verbose:
print(" waiting for worker to say it caught the exception")
worker_saw_exception.wait(timeout=10)
self.assertTrue(t.finished)
if verbose:
print(" all OK -- joining worker")
if t.finished:
t.join()
# else the thread is still running, and we have no way to kill it
def test_limbo_cleanup(self):
# Issue 7481: Failure to start thread should cleanup the limbo map.
def fail_new_thread(*args):
raise threading.ThreadError()
_start_new_thread = threading._start_new_thread
threading._start_new_thread = fail_new_thread
try:
t = threading.Thread(target=lambda: None)
self.assertRaises(threading.ThreadError, t.start)
self.assertFalse(
t in threading._limbo,
"Failed to cleanup _limbo map on failure of Thread.start().")
finally:
threading._start_new_thread = _start_new_thread
def test_finalize_runnning_thread(self):
# Issue 1402: the PyGILState_Ensure / _Release functions may be called
# very late on python exit: on deallocation of a running thread for
# example.
import_module("ctypes")
rc, out, err = assert_python_failure("-c", """if 1:
import ctypes, sys, time, _thread
# This lock is used as a simple event variable.
ready = _thread.allocate_lock()
ready.acquire()
# Module globals are cleared before __del__ is run
# So we save the functions in class dict
class C:
ensure = ctypes.pythonapi.PyGILState_Ensure
release = ctypes.pythonapi.PyGILState_Release
def __del__(self):
state = self.ensure()
self.release(state)
def waitingThread():
x = C()
ready.release()
time.sleep(100)
_thread.start_new_thread(waitingThread, ())
ready.acquire() # Be sure the other thread is waiting.
sys.exit(42)
""")
self.assertEqual(rc, 42)
def test_finalize_with_trace(self):
# Issue1733757
# Avoid a deadlock when sys.settrace steps into threading._shutdown
assert_python_ok("-c", """if 1:
import sys, threading
# A deadlock-killer, to prevent the
# testsuite to hang forever
def killer():
import os, time
time.sleep(2)
print('program blocked; aborting')
os._exit(2)
t = threading.Thread(target=killer)
t.daemon = True
t.start()
# This is the trace function
def func(frame, event, arg):
threading.current_thread()
return func
sys.settrace(func)
""")
def test_join_nondaemon_on_shutdown(self):
# Issue 1722344
# Raising SystemExit skipped threading._shutdown
rc, out, err = assert_python_ok("-c", """if 1:
import threading
from time import sleep
def child():
sleep(1)
# As a non-daemon thread we SHOULD wake up and nothing
# should be torn down yet
print("Woke up, sleep function is:", sleep)
threading.Thread(target=child).start()
raise SystemExit
""")
self.assertEqual(out.strip(),
b"Woke up, sleep function is: <built-in function sleep>")
self.assertEqual(err, b"")
def test_enumerate_after_join(self):
# Try hard to trigger #1703448: a thread is still returned in
# threading.enumerate() after it has been join()ed.
enum = threading.enumerate
old_interval = sys.getswitchinterval()
try:
for i in range(1, 100):
sys.setswitchinterval(i * 0.0002)
t = threading.Thread(target=lambda: None)
t.start()
t.join()
l = enum()
self.assertNotIn(t, l,
"#1703448 triggered after %d trials: %s" % (i, l))
finally:
sys.setswitchinterval(old_interval)
def test_no_refcycle_through_target(self):
class RunSelfFunction(object):
def __init__(self, should_raise):
# The links in this refcycle from Thread back to self
# should be cleaned up when the thread completes.
self.should_raise = should_raise
self.thread = threading.Thread(target=self._run,
args=(self,),
kwargs={'yet_another':self})
self.thread.start()
def _run(self, other_ref, yet_another):
if self.should_raise:
raise SystemExit
cyclic_object = RunSelfFunction(should_raise=False)
weak_cyclic_object = weakref.ref(cyclic_object)
cyclic_object.thread.join()
del cyclic_object
self.assertIsNone(weak_cyclic_object(),
msg=('%d references still around' %
sys.getrefcount(weak_cyclic_object())))
raising_cyclic_object = RunSelfFunction(should_raise=True)
weak_raising_cyclic_object = weakref.ref(raising_cyclic_object)
raising_cyclic_object.thread.join()
del raising_cyclic_object
self.assertIsNone(weak_raising_cyclic_object(),
msg=('%d references still around' %
sys.getrefcount(weak_raising_cyclic_object())))
def test_old_threading_api(self):
# Just a quick sanity check to make sure the old method names are
# still present
t = threading.Thread()
t.isDaemon()
t.setDaemon(True)
t.getName()
t.setName("name")
with self.assertWarnsRegex(DeprecationWarning, 'use is_alive()'):
t.isAlive()
e = threading.Event()
e.isSet()
threading.activeCount()
def test_repr_daemon(self):
t = threading.Thread()
self.assertNotIn('daemon', repr(t))
t.daemon = True
self.assertIn('daemon', repr(t))
def test_daemon_param(self):
t = threading.Thread()
self.assertFalse(t.daemon)
t = threading.Thread(daemon=False)
self.assertFalse(t.daemon)
t = threading.Thread(daemon=True)
self.assertTrue(t.daemon)
@unittest.skipUnless(hasattr(os, 'fork'), 'test needs fork()')
def test_dummy_thread_after_fork(self):
# Issue #14308: a dummy thread in the active list doesn't mess up
# the after-fork mechanism.
code = """if 1:
import _thread, threading, os, time
def background_thread(evt):
# Creates and registers the _DummyThread instance
threading.current_thread()
evt.set()
time.sleep(10)
evt = threading.Event()
_thread.start_new_thread(background_thread, (evt,))
evt.wait()
assert threading.active_count() == 2, threading.active_count()
if os.fork() == 0:
assert threading.active_count() == 1, threading.active_count()
os._exit(0)
else:
os.wait()
"""
_, out, err = assert_python_ok("-c", code)
self.assertEqual(out, b'')
self.assertEqual(err, b'')
@unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()")
def test_is_alive_after_fork(self):
# Try hard to trigger #18418: is_alive() could sometimes be True on
# threads that vanished after a fork.
old_interval = sys.getswitchinterval()
self.addCleanup(sys.setswitchinterval, old_interval)
# Make the bug more likely to manifest.
test.support.setswitchinterval(1e-6)
for i in range(20):
t = threading.Thread(target=lambda: None)
t.start()
pid = os.fork()
if pid == 0:
os._exit(11 if t.is_alive() else 10)
else:
t.join()
pid, status = os.waitpid(pid, 0)
self.assertTrue(os.WIFEXITED(status))
self.assertEqual(10, os.WEXITSTATUS(status))
def test_main_thread(self):
main = threading.main_thread()
self.assertEqual(main.name, 'MainThread')
self.assertEqual(main.ident, threading.current_thread().ident)
self.assertEqual(main.ident, threading.get_ident())
def f():
self.assertNotEqual(threading.main_thread().ident,
threading.current_thread().ident)
th = threading.Thread(target=f)
th.start()
th.join()
@unittest.skipUnless(hasattr(os, 'fork'), "test needs os.fork()")
@unittest.skipUnless(hasattr(os, 'waitpid'), "test needs os.waitpid()")
def test_main_thread_after_fork(self):
code = """if 1:
import os, threading
pid = os.fork()
if pid == 0:
main = threading.main_thread()
print(main.name)
print(main.ident == threading.current_thread().ident)
print(main.ident == threading.get_ident())
else:
os.waitpid(pid, 0)
"""
_, out, err = assert_python_ok("-c", code)
data = out.decode().replace('\r', '')
self.assertEqual(err, b"")
self.assertEqual(data, "MainThread\nTrue\nTrue\n")
@unittest.skipIf(sys.platform in platforms_to_skip, "due to known OS bug")
@unittest.skipUnless(hasattr(os, 'fork'), "test needs os.fork()")
@unittest.skipUnless(hasattr(os, 'waitpid'), "test needs os.waitpid()")
def test_main_thread_after_fork_from_nonmain_thread(self):
code = """if 1:
import os, threading, sys
def f():
pid = os.fork()
if pid == 0:
main = threading.main_thread()
print(main.name)
print(main.ident == threading.current_thread().ident)
print(main.ident == threading.get_ident())
# stdout is fully buffered because not a tty,
# we have to flush before exit.
sys.stdout.flush()
else:
os.waitpid(pid, 0)
th = threading.Thread(target=f)
th.start()
th.join()
"""
_, out, err = assert_python_ok("-c", code)
data = out.decode().replace('\r', '')
self.assertEqual(err, b"")
self.assertEqual(data, "Thread-1\nTrue\nTrue\n")
@requires_type_collecting
def test_main_thread_during_shutdown(self):
# bpo-31516: current_thread() should still point to the main thread
# at shutdown
code = """if 1:
import gc, threading
main_thread = threading.current_thread()
assert main_thread is threading.main_thread() # sanity check
class RefCycle:
def __init__(self):
self.cycle = self
def __del__(self):
print("GC:",
threading.current_thread() is main_thread,
threading.main_thread() is main_thread,
threading.enumerate() == [main_thread])
RefCycle()
gc.collect() # sanity check
x = RefCycle()
"""
_, out, err = assert_python_ok("-c", code)
data = out.decode()
self.assertEqual(err, b"")
self.assertEqual(data.splitlines(),
["GC: True True True"] * 2)
def test_finalization_shutdown(self):
# bpo-36402: Py_Finalize() calls threading._shutdown() which must wait
# until Python thread states of all non-daemon threads get deleted.
#
# Test similar to SubinterpThreadingTests.test_threads_join_2(), but
# test the finalization of the main interpreter.
code = """if 1:
import os
import threading
import time
import random
def random_sleep():
seconds = random.random() * 0.010
time.sleep(seconds)
class Sleeper:
def __del__(self):
random_sleep()
tls = threading.local()
def f():
# Sleep a bit so that the thread is still running when
# Py_Finalize() is called.
random_sleep()
tls.x = Sleeper()
random_sleep()
threading.Thread(target=f).start()
random_sleep()
"""
rc, out, err = assert_python_ok("-c", code)
self.assertEqual(err, b"")
def test_tstate_lock(self):
# Test an implementation detail of Thread objects.
started = _thread.allocate_lock()
finish = _thread.allocate_lock()
started.acquire()
finish.acquire()
def f():
started.release()
finish.acquire()
time.sleep(0.01)
# The tstate lock is None until the thread is started
t = threading.Thread(target=f)
self.assertIs(t._tstate_lock, None)
t.start()
started.acquire()
self.assertTrue(t.is_alive())
# The tstate lock can't be acquired when the thread is running
# (or suspended).
tstate_lock = t._tstate_lock
self.assertFalse(tstate_lock.acquire(timeout=0), False)
finish.release()
# When the thread ends, the state_lock can be successfully
# acquired.
self.assertTrue(tstate_lock.acquire(timeout=5), False)
# But is_alive() is still True: we hold _tstate_lock now, which
# prevents is_alive() from knowing the thread's end-of-life C code
# is done.
self.assertTrue(t.is_alive())
# Let is_alive() find out the C code is done.
tstate_lock.release()
self.assertFalse(t.is_alive())
# And verify the thread disposed of _tstate_lock.
self.assertIsNone(t._tstate_lock)
t.join()
def test_repr_stopped(self):
# Verify that "stopped" shows up in repr(Thread) appropriately.
started = _thread.allocate_lock()
finish = _thread.allocate_lock()
started.acquire()
finish.acquire()
def f():
started.release()
finish.acquire()
t = threading.Thread(target=f)
t.start()
started.acquire()
self.assertIn("started", repr(t))
finish.release()
# "stopped" should appear in the repr in a reasonable amount of time.
# Implementation detail: as of this writing, that's trivially true
# if .join() is called, and almost trivially true if .is_alive() is
# called. The detail we're testing here is that "stopped" shows up
# "all on its own".
LOOKING_FOR = "stopped"
for i in range(500):
if LOOKING_FOR in repr(t):
break
time.sleep(0.01)
self.assertIn(LOOKING_FOR, repr(t)) # we waited at least 5 seconds
t.join()
def test_BoundedSemaphore_limit(self):
# BoundedSemaphore should raise ValueError if released too often.
for limit in range(1, 10):
bs = threading.BoundedSemaphore(limit)
threads = [threading.Thread(target=bs.acquire)
for _ in range(limit)]
for t in threads:
t.start()
for t in threads:
t.join()
threads = [threading.Thread(target=bs.release)
for _ in range(limit)]
for t in threads:
t.start()
for t in threads:
t.join()
self.assertRaises(ValueError, bs.release)
@cpython_only
def test_frame_tstate_tracing(self):
# Issue #14432: Crash when a generator is created in a C thread that is
# destroyed while the generator is still used. The issue was that a
# generator contains a frame, and the frame kept a reference to the
# Python state of the destroyed C thread. The crash occurs when a trace
# function is setup.
def noop_trace(frame, event, arg):
# no operation
return noop_trace
def generator():
while 1:
yield "generator"
def callback():
if callback.gen is None:
callback.gen = generator()
return next(callback.gen)
callback.gen = None
old_trace = sys.gettrace()
sys.settrace(noop_trace)
try:
# Install a trace function
threading.settrace(noop_trace)
# Create a generator in a C thread which exits after the call
import _testcapi
_testcapi.call_in_temporary_c_thread(callback)
# Call the generator in a different Python thread, check that the
# generator didn't keep a reference to the destroyed thread state
for test in range(3):
# The trace function is still called here
callback()
finally:
sys.settrace(old_trace)
@cpython_only
def test_shutdown_locks(self):
for daemon in (False, True):
with self.subTest(daemon=daemon):
event = threading.Event()
thread = threading.Thread(target=event.wait, daemon=daemon)
# Thread.start() must add lock to _shutdown_locks,
# but only for non-daemon thread
thread.start()
tstate_lock = thread._tstate_lock
if not daemon:
self.assertIn(tstate_lock, threading._shutdown_locks)
else:
self.assertNotIn(tstate_lock, threading._shutdown_locks)
# unblock the thread and join it
event.set()
thread.join()
# Thread._stop() must remove tstate_lock from _shutdown_locks.
# Daemon threads must never add it to _shutdown_locks.
self.assertNotIn(tstate_lock, threading._shutdown_locks)
class ThreadJoinOnShutdown(BaseTestCase):
def _run_and_join(self, script):
script = """if 1:
import sys, os, time, threading
# a thread, which waits for the main program to terminate
def joiningfunc(mainthread):
mainthread.join()
print('end of thread')
# stdout is fully buffered because not a tty, we have to flush
# before exit.
sys.stdout.flush()
\n""" + script
rc, out, err = assert_python_ok("-c", script)
data = out.decode().replace('\r', '')
self.assertEqual(data, "end of main\nend of thread\n")
def test_1_join_on_shutdown(self):
# The usual case: on exit, wait for a non-daemon thread
script = """if 1:
import os
t = threading.Thread(target=joiningfunc,
args=(threading.current_thread(),))
t.start()
time.sleep(0.1)
print('end of main')
"""
self._run_and_join(script)
@unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()")
@unittest.skipIf(sys.platform in platforms_to_skip, "due to known OS bug")
def test_2_join_in_forked_process(self):
# Like the test above, but from a forked interpreter
script = """if 1:
childpid = os.fork()
if childpid != 0:
os.waitpid(childpid, 0)
sys.exit(0)
t = threading.Thread(target=joiningfunc,
args=(threading.current_thread(),))
t.start()
print('end of main')
"""
self._run_and_join(script)
@unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()")
@unittest.skipIf(sys.platform in platforms_to_skip, "due to known OS bug")
def test_3_join_in_forked_from_thread(self):
# Like the test above, but fork() was called from a worker thread
# In the forked process, the main Thread object must be marked as stopped.
script = """if 1:
main_thread = threading.current_thread()
def worker():
childpid = os.fork()
if childpid != 0:
os.waitpid(childpid, 0)
sys.exit(0)
t = threading.Thread(target=joiningfunc,
args=(main_thread,))
print('end of main')
t.start()
t.join() # Should not block: main_thread is already stopped
w = threading.Thread(target=worker)
w.start()
"""
self._run_and_join(script)
@unittest.skipIf(sys.platform in platforms_to_skip, "due to known OS bug")
def test_4_daemon_threads(self):
# Check that a daemon thread cannot crash the interpreter on shutdown
# by manipulating internal structures that are being disposed of in
# the main thread.
script = """if True:
import os
import random
import sys
import time
import threading
thread_has_run = set()
def random_io():
'''Loop for a while sleeping random tiny amounts and doing some I/O.'''
while True:
with open(os.__file__, 'rb') as in_f:
stuff = in_f.read(200)
with open(os.devnull, 'wb') as null_f:
null_f.write(stuff)
time.sleep(random.random() / 1995)
thread_has_run.add(threading.current_thread())
def main():
count = 0
for _ in range(40):
new_thread = threading.Thread(target=random_io)
new_thread.daemon = True
new_thread.start()
count += 1
while len(thread_has_run) < count:
time.sleep(0.001)
# Trigger process shutdown
sys.exit(0)
main()
"""
rc, out, err = assert_python_ok('-c', script)
self.assertFalse(err)
@unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()")
@unittest.skipIf(sys.platform in platforms_to_skip, "due to known OS bug")
def test_reinit_tls_after_fork(self):
# Issue #13817: fork() would deadlock in a multithreaded program with
# the ad-hoc TLS implementation.
def do_fork_and_wait():
# just fork a child process and wait it
pid = os.fork()
if pid > 0:
os.waitpid(pid, 0)
else:
os._exit(0)
# start a bunch of threads that will fork() child processes
threads = []
for i in range(16):
t = threading.Thread(target=do_fork_and_wait)
threads.append(t)
t.start()
for t in threads:
t.join()
@unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()")
def test_clear_threads_states_after_fork(self):
# Issue #17094: check that threads states are cleared after fork()
# start a bunch of threads
threads = []
for i in range(16):
t = threading.Thread(target=lambda : time.sleep(0.3))
threads.append(t)
t.start()
pid = os.fork()
if pid == 0:
# check that threads states have been cleared
if len(sys._current_frames()) == 1:
os._exit(0)
else:
os._exit(1)
else:
_, status = os.waitpid(pid, 0)
self.assertEqual(0, status)
for t in threads:
t.join()
class SubinterpThreadingTests(BaseTestCase):
def test_threads_join(self):
# Non-daemon threads should be joined at subinterpreter shutdown
# (issue #18808)
r, w = os.pipe()
self.addCleanup(os.close, r)
self.addCleanup(os.close, w)
code = r"""if 1:
import os
import random
import threading
import time
def random_sleep():
seconds = random.random() * 0.010
time.sleep(seconds)
def f():
# Sleep a bit so that the thread is still running when
# Py_EndInterpreter is called.
random_sleep()
os.write(%d, b"x")
threading.Thread(target=f).start()
random_sleep()
""" % (w,)
ret = test.support.run_in_subinterp(code)
self.assertEqual(ret, 0)
# The thread was joined properly.
self.assertEqual(os.read(r, 1), b"x")
def test_threads_join_2(self):
# Same as above, but a delay gets introduced after the thread's
# Python code returned but before the thread state is deleted.
# To achieve this, we register a thread-local object which sleeps
# a bit when deallocated.
r, w = os.pipe()
self.addCleanup(os.close, r)
self.addCleanup(os.close, w)
code = r"""if 1:
import os
import random
import threading
import time
def random_sleep():
seconds = random.random() * 0.010
time.sleep(seconds)
class Sleeper:
def __del__(self):
random_sleep()
tls = threading.local()
def f():
# Sleep a bit so that the thread is still running when
# Py_EndInterpreter is called.
random_sleep()
tls.x = Sleeper()
os.write(%d, b"x")
threading.Thread(target=f).start()
random_sleep()
""" % (w,)
ret = test.support.run_in_subinterp(code)
self.assertEqual(ret, 0)
# The thread was joined properly.
self.assertEqual(os.read(r, 1), b"x")
@cpython_only
def test_daemon_threads_fatal_error(self):
subinterp_code = r"""if 1:
import os
import threading
import time
def f():
# Make sure the daemon thread is still running when
# Py_EndInterpreter is called.
time.sleep(10)
threading.Thread(target=f, daemon=True).start()
"""
script = r"""if 1:
import _testcapi
_testcapi.run_in_subinterp(%r)
""" % (subinterp_code,)
with test.support.SuppressCrashReport():
rc, out, err = assert_python_failure("-c", script)
self.assertIn("Fatal Python error: Py_EndInterpreter: "
"not the last thread", err.decode())
class ThreadingExceptionTests(BaseTestCase):
# A RuntimeError should be raised if Thread.start() is called
# multiple times.
def test_start_thread_again(self):
thread = threading.Thread()
thread.start()
self.assertRaises(RuntimeError, thread.start)
thread.join()
def test_joining_current_thread(self):
current_thread = threading.current_thread()
self.assertRaises(RuntimeError, current_thread.join);
def test_joining_inactive_thread(self):
thread = threading.Thread()
self.assertRaises(RuntimeError, thread.join)
def test_daemonize_active_thread(self):
thread = threading.Thread()
thread.start()
self.assertRaises(RuntimeError, setattr, thread, "daemon", True)
thread.join()
def test_releasing_unacquired_lock(self):
lock = threading.Lock()
self.assertRaises(RuntimeError, lock.release)
def test_recursion_limit(self):
# Issue 9670
# test that excessive recursion within a non-main thread causes
# an exception rather than crashing the interpreter on platforms
# like Mac OS X or FreeBSD which have small default stack sizes
# for threads
script = """if True:
import threading
def recurse():
return recurse()
def outer():
try:
recurse()
except RecursionError:
pass
w = threading.Thread(target=outer)
w.start()
w.join()
print('end of main thread')
"""
expected_output = "end of main thread\n"
p = subprocess.Popen([sys.executable, "-c", script],
stdout=subprocess.PIPE, stderr=subprocess.PIPE)
stdout, stderr = p.communicate()
data = stdout.decode().replace('\r', '')
self.assertEqual(p.returncode, 0, "Unexpected error: " + stderr.decode())
self.assertEqual(data, expected_output)
def test_print_exception(self):
script = r"""if True:
import threading
import time
running = False
def run():
global running
running = True
while running:
time.sleep(0.01)
1/0
t = threading.Thread(target=run)
t.start()
while not running:
time.sleep(0.01)
running = False
t.join()
"""
rc, out, err = assert_python_ok("-c", script)
self.assertEqual(out, b'')
err = err.decode()
self.assertIn("Exception in thread", err)
self.assertIn("Traceback (most recent call last):", err)
self.assertIn("ZeroDivisionError", err)
self.assertNotIn("Unhandled exception", err)
@requires_type_collecting
def test_print_exception_stderr_is_none_1(self):
script = r"""if True:
import sys
import threading
import time
running = False
def run():
global running
running = True
while running:
time.sleep(0.01)
1/0
t = threading.Thread(target=run)
t.start()
while not running:
time.sleep(0.01)
sys.stderr = None
running = False
t.join()
"""
rc, out, err = assert_python_ok("-c", script)
self.assertEqual(out, b'')
err = err.decode()
self.assertIn("Exception in thread", err)
self.assertIn("Traceback (most recent call last):", err)
self.assertIn("ZeroDivisionError", err)
self.assertNotIn("Unhandled exception", err)
def test_print_exception_stderr_is_none_2(self):
script = r"""if True:
import sys
import threading
import time
running = False
def run():
global running
running = True
while running:
time.sleep(0.01)
1/0
sys.stderr = None
t = threading.Thread(target=run)
t.start()
while not running:
time.sleep(0.01)
running = False
t.join()
"""
rc, out, err = assert_python_ok("-c", script)
self.assertEqual(out, b'')
self.assertNotIn("Unhandled exception", err.decode())
def test_bare_raise_in_brand_new_thread(self):
def bare_raise():
raise
class Issue27558(threading.Thread):
exc = None
def run(self):
try:
bare_raise()
except Exception as exc:
self.exc = exc
thread = Issue27558()
thread.start()
thread.join()
self.assertIsNotNone(thread.exc)
self.assertIsInstance(thread.exc, RuntimeError)
# explicitly break the reference cycle to not leak a dangling thread
thread.exc = None
class ThreadRunFail(threading.Thread):
def run(self):
raise ValueError("run failed")
class ExceptHookTests(BaseTestCase):
def test_excepthook(self):
with support.captured_output("stderr") as stderr:
thread = ThreadRunFail(name="excepthook thread")
thread.start()
thread.join()
stderr = stderr.getvalue().strip()
self.assertIn(f'Exception in thread {thread.name}:\n', stderr)
self.assertIn('Traceback (most recent call last):\n', stderr)
self.assertIn(' raise ValueError("run failed")', stderr)
self.assertIn('ValueError: run failed', stderr)
@support.cpython_only
def test_excepthook_thread_None(self):
# threading.excepthook called with thread=None: log the thread
# identifier in this case.
with support.captured_output("stderr") as stderr:
try:
raise ValueError("bug")
except Exception as exc:
args = threading.ExceptHookArgs([*sys.exc_info(), None])
try:
threading.excepthook(args)
finally:
# Explicitly break a reference cycle
args = None
stderr = stderr.getvalue().strip()
self.assertIn(f'Exception in thread {threading.get_ident()}:\n', stderr)
self.assertIn('Traceback (most recent call last):\n', stderr)
self.assertIn(' raise ValueError("bug")', stderr)
self.assertIn('ValueError: bug', stderr)
def test_system_exit(self):
class ThreadExit(threading.Thread):
def run(self):
sys.exit(1)
# threading.excepthook() silently ignores SystemExit
with support.captured_output("stderr") as stderr:
thread = ThreadExit()
thread.start()
thread.join()
self.assertEqual(stderr.getvalue(), '')
def test_custom_excepthook(self):
args = None
def hook(hook_args):
nonlocal args
args = hook_args
try:
with support.swap_attr(threading, 'excepthook', hook):
thread = ThreadRunFail()
thread.start()
thread.join()
self.assertEqual(args.exc_type, ValueError)
self.assertEqual(str(args.exc_value), 'run failed')
self.assertEqual(args.exc_traceback, args.exc_value.__traceback__)
self.assertIs(args.thread, thread)
finally:
# Break reference cycle
args = None
def test_custom_excepthook_fail(self):
def threading_hook(args):
raise ValueError("threading_hook failed")
err_str = None
def sys_hook(exc_type, exc_value, exc_traceback):
nonlocal err_str
err_str = str(exc_value)
with support.swap_attr(threading, 'excepthook', threading_hook), \
support.swap_attr(sys, 'excepthook', sys_hook), \
support.captured_output('stderr') as stderr:
thread = ThreadRunFail()
thread.start()
thread.join()
self.assertEqual(stderr.getvalue(),
'Exception in threading.excepthook:\n')
self.assertEqual(err_str, 'threading_hook failed')
class TimerTests(BaseTestCase):
def setUp(self):
BaseTestCase.setUp(self)
self.callback_args = []
self.callback_event = threading.Event()
def test_init_immutable_default_args(self):
# Issue 17435: constructor defaults were mutable objects, they could be
# mutated via the object attributes and affect other Timer objects.
timer1 = threading.Timer(0.01, self._callback_spy)
timer1.start()
self.callback_event.wait()
timer1.args.append("blah")
timer1.kwargs["foo"] = "bar"
self.callback_event.clear()
timer2 = threading.Timer(0.01, self._callback_spy)
timer2.start()
self.callback_event.wait()
self.assertEqual(len(self.callback_args), 2)
self.assertEqual(self.callback_args, [((), {}), ((), {})])
timer1.join()
timer2.join()
def _callback_spy(self, *args, **kwargs):
self.callback_args.append((args[:], kwargs.copy()))
self.callback_event.set()
class LockTests(lock_tests.LockTests):
locktype = staticmethod(threading.Lock)
class PyRLockTests(lock_tests.RLockTests):
locktype = staticmethod(threading._PyRLock)
@unittest.skipIf(threading._CRLock is None, 'RLock not implemented in C')
class CRLockTests(lock_tests.RLockTests):
locktype = staticmethod(threading._CRLock)
class EventTests(lock_tests.EventTests):
eventtype = staticmethod(threading.Event)
class ConditionAsRLockTests(lock_tests.RLockTests):
# Condition uses an RLock by default and exports its API.
locktype = staticmethod(threading.Condition)
class ConditionTests(lock_tests.ConditionTests):
condtype = staticmethod(threading.Condition)
class SemaphoreTests(lock_tests.SemaphoreTests):
semtype = staticmethod(threading.Semaphore)
class BoundedSemaphoreTests(lock_tests.BoundedSemaphoreTests):
semtype = staticmethod(threading.BoundedSemaphore)
class BarrierTests(lock_tests.BarrierTests):
barriertype = staticmethod(threading.Barrier)
class MiscTestCase(unittest.TestCase):
def test__all__(self):
extra = {"ThreadError"}
blacklist = {'currentThread', 'activeCount'}
support.check__all__(self, threading, ('threading', '_thread'),
extra=extra, blacklist=blacklist)
class InterruptMainTests(unittest.TestCase):
def test_interrupt_main_subthread(self):
# Calling start_new_thread with a function that executes interrupt_main
# should raise KeyboardInterrupt upon completion.
def call_interrupt():
_thread.interrupt_main()
t = threading.Thread(target=call_interrupt)
with self.assertRaises(KeyboardInterrupt):
t.start()
t.join()
t.join()
def test_interrupt_main_mainthread(self):
# Make sure that if interrupt_main is called in main thread that
# KeyboardInterrupt is raised instantly.
with self.assertRaises(KeyboardInterrupt):
_thread.interrupt_main()
def test_interrupt_main_noerror(self):
handler = signal.getsignal(signal.SIGINT)
try:
# No exception should arise.
signal.signal(signal.SIGINT, signal.SIG_IGN)
_thread.interrupt_main()
signal.signal(signal.SIGINT, signal.SIG_DFL)
_thread.interrupt_main()
finally:
# Restore original handler
signal.signal(signal.SIGINT, handler)
if __name__ == "__main__":
unittest.main()
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