"""
Tests for the threading module.
"""
import test.support
from test.support import threading_helper, requires_subprocess, requires_gil_enabled
from test.support import verbose, cpython_only, os_helper
from test.support.import_helper import import_module
from test.support.script_helper import assert_python_ok, assert_python_failure
from test.support import force_not_colorized
import random
import sys
import _thread
import threading
import time
import unittest
import weakref
import os
import subprocess
import signal
import textwrap
import traceback
import warnings
from unittest import mock
from test import lock_tests
from test import support
try:
from test.support import interpreters
except ImportError:
interpreters = None
threading_helper.requires_working_threading(module=True)
# 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')
def skip_unless_reliable_fork(test):
if not support.has_fork_support:
return unittest.skip("requires working os.fork()")(test)
if sys.platform in platforms_to_skip:
return unittest.skip("due to known OS bug related to thread+fork")(test)
if support.HAVE_ASAN_FORK_BUG:
return unittest.skip("libasan has a pthread_create() dead lock related to thread+fork")(test)
if support.check_sanitizer(thread=True):
return unittest.skip("TSAN doesn't support threads after fork")(test)
return test
def requires_subinterpreters(meth):
"""Decorator to skip a test if subinterpreters are not supported."""
return unittest.skipIf(interpreters is None,
'subinterpreters required')(meth)
def restore_default_excepthook(testcase):
testcase.addCleanup(setattr, threading, 'excepthook', threading.excepthook)
threading.excepthook = threading.__excepthook__
# 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 = threading_helper.threading_setup()
def tearDown(self):
threading_helper.threading_cleanup(*self._threads)
test.support.reap_children()
class ThreadTests(BaseTestCase):
maxDiff = 9999
@cpython_only
def test_name(self):
def func(): pass
thread = threading.Thread(name="myname1")
self.assertEqual(thread.name, "myname1")
# Convert int name to str
thread = threading.Thread(name=123)
self.assertEqual(thread.name, "123")
# target name is ignored if name is specified
thread = threading.Thread(target=func, name="myname2")
self.assertEqual(thread.name, "myname2")
with mock.patch.object(threading, '_counter', return_value=2):
thread = threading.Thread(name="")
self.assertEqual(thread.name, "Thread-2")
with mock.patch.object(threading, '_counter', return_value=3):
thread = threading.Thread()
self.assertEqual(thread.name, "Thread-3")
with mock.patch.object(threading, '_counter', return_value=5):
thread = threading.Thread(target=func)
self.assertEqual(thread.name, "Thread-5 (func)")
def test_args_argument(self):
# bpo-45735: Using list or tuple as *args* in constructor could
# achieve the same effect.
num_list = [1]
num_tuple = (1,)
str_list = ["str"]
str_tuple = ("str",)
list_in_tuple = ([1],)
tuple_in_list = [(1,)]
test_cases = (
(num_list, lambda arg: self.assertEqual(arg, 1)),
(num_tuple, lambda arg: self.assertEqual(arg, 1)),
(str_list, lambda arg: self.assertEqual(arg, "str")),
(str_tuple, lambda arg: self.assertEqual(arg, "str")),
(list_in_tuple, lambda arg: self.assertEqual(arg, [1])),
(tuple_in_list, lambda arg: self.assertEqual(arg, (1,)))
)
for args, target in test_cases:
with self.subTest(target=target, args=args):
t = threading.Thread(target=target, args=args)
t.start()
t.join()
def test_lock_no_args(self):
threading.Lock() # works
self.assertRaises(TypeError, threading.Lock, 1)
self.assertRaises(TypeError, threading.Lock, a=1)
self.assertRaises(TypeError, threading.Lock, 1, 2, a=1, b=2)
def test_lock_no_subclass(self):
# Intentionally disallow subclasses of threading.Lock because they have
# never been allowed, so why start now just because the type is public?
with self.assertRaises(TypeError):
class MyLock(threading.Lock): pass
def test_lock_or_none(self):
import types
self.assertIsInstance(threading.Lock | None, types.UnionType)
# 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.current_thread().ident)
def f():
ident.append(threading.current_thread().ident)
done.set()
done = threading.Event()
ident = []
with threading_helper.wait_threads_exit():
tid = _thread.start_new_thread(f, ())
done.wait()
self.assertEqual(ident[0], tid)
# 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.
dummy_thread = None
error = None
def f(mutex):
try:
nonlocal dummy_thread
nonlocal error
# Calling current_thread() forces an entry for the foreign
# thread to get made in the threading._active map.
dummy_thread = threading.current_thread()
tid = dummy_thread.ident
self.assertIn(tid, threading._active)
self.assertIsInstance(dummy_thread, threading._DummyThread)
self.assertIs(threading._active.get(tid), dummy_thread)
# gh-29376
self.assertTrue(
dummy_thread.is_alive(),
'Expected _DummyThread to be considered alive.'
)
self.assertIn('_DummyThread', repr(dummy_thread))
except BaseException as e:
error = e
finally:
mutex.release()
mutex = threading.Lock()
mutex.acquire()
with threading_helper.wait_threads_exit():
tid = _thread.start_new_thread(f, (mutex,))
# Wait for the thread to finish.
mutex.acquire()
if error is not None:
raise error
self.assertEqual(tid, dummy_thread.ident)
# Issue gh-106236:
with self.assertRaises(RuntimeError):
dummy_thread.join()
dummy_thread._started.clear()
with self.assertRaises(RuntimeError):
dummy_thread.is_alive()
# Busy wait for the following condition: after the thread dies, the
# related dummy thread must be removed from threading._active.
timeout = 5
timeout_at = time.monotonic() + timeout
while time.monotonic() < timeout_at:
if threading._active.get(dummy_thread.ident) is not dummy_thread:
break
time.sleep(.1)
else:
self.fail('It was expected that the created threading._DummyThread was removed from threading._active.')
# 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=support.SHORT_TIMEOUT)
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, **kwargs):
raise threading.ThreadError()
_start_joinable_thread = threading._start_joinable_thread
threading._start_joinable_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_joinable_thread = _start_joinable_thread
def test_finalize_running_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.
if support.check_sanitizer(thread=True):
# the thread running `time.sleep(100)` below will still be alive
# at process exit
self.skipTest("TSAN would report thread leak")
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
if support.check_sanitizer(thread=True):
# the thread running `time.sleep(2)` below will still be alive
# at process exit
self.skipTest("TSAN would report thread leak")
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):
support.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_join_from_multiple_threads(self):
# Thread.join() should be thread-safe
errors = []
def worker():
time.sleep(0.005)
def joiner(thread):
try:
thread.join()
except Exception as e:
errors.append(e)
for N in range(2, 20):
threads = [threading.Thread(target=worker)]
for i in range(N):
threads.append(threading.Thread(target=joiner,
args=(threads[0],)))
for t in threads:
t.start()
time.sleep(0.01)
for t in threads:
t.join()
if errors:
raise errors[0]
def test_join_with_timeout(self):
lock = _thread.allocate_lock()
lock.acquire()
def worker():
lock.acquire()
thread = threading.Thread(target=worker)
thread.start()
thread.join(timeout=0.01)
assert thread.is_alive()
lock.release()
thread.join()
assert not thread.is_alive()
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
restore_default_excepthook(self)
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()
with self.assertWarnsRegex(DeprecationWarning,
r'get the daemon attribute'):
t.isDaemon()
with self.assertWarnsRegex(DeprecationWarning,
r'set the daemon attribute'):
t.setDaemon(True)
with self.assertWarnsRegex(DeprecationWarning,
r'get the name attribute'):
t.getName()
with self.assertWarnsRegex(DeprecationWarning,
r'set the name attribute'):
t.setName("name")
e = threading.Event()
with self.assertWarnsRegex(DeprecationWarning, 'use is_set()'):
e.isSet()
cond = threading.Condition()
cond.acquire()
with self.assertWarnsRegex(DeprecationWarning, 'use notify_all()'):
cond.notifyAll()
with self.assertWarnsRegex(DeprecationWarning, 'use active_count()'):
threading.activeCount()
with self.assertWarnsRegex(DeprecationWarning, 'use current_thread()'):
threading.currentThread()
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)
@skip_unless_reliable_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, warnings
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()
with warnings.catch_warnings(record=True) as ws:
warnings.filterwarnings(
"always", category=DeprecationWarning)
if os.fork() == 0:
assert threading.active_count() == 1, threading.active_count()
os._exit(0)
else:
assert ws[0].category == DeprecationWarning, ws[0]
assert 'fork' in str(ws[0].message), ws[0]
os.wait()
"""
_, out, err = assert_python_ok("-c", code)
self.assertEqual(out, b'')
self.assertEqual(err, b'')
@skip_unless_reliable_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()
# Ignore the warning about fork with threads.
with warnings.catch_warnings(category=DeprecationWarning,
action="ignore"):
if (pid := os.fork()) == 0:
os._exit(11 if t.is_alive() else 10)
else:
t.join()
support.wait_process(pid, exitcode=10)
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()
@skip_unless_reliable_fork
@unittest.skipUnless(hasattr(os, 'waitpid'), "test needs os.waitpid()")
def test_main_thread_after_fork(self):
code = """if 1:
import os, threading
from test import support
ident = threading.get_ident()
pid = os.fork()
if pid == 0:
print("current ident", threading.get_ident() == ident)
main = threading.main_thread()
print("main", main.name)
print("main ident", main.ident == ident)
print("current is main", threading.current_thread() is main)
else:
support.wait_process(pid, exitcode=0)
"""
_, out, err = assert_python_ok("-c", code)
data = out.decode().replace('\r', '')
self.assertEqual(err, b"")
self.assertEqual(data,
"current ident True\n"
"main MainThread\n"
"main ident True\n"
"current is main True\n")
@skip_unless_reliable_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, warnings
from test import support
def func():
ident = threading.get_ident()
with warnings.catch_warnings(record=True) as ws:
warnings.filterwarnings(
"always", category=DeprecationWarning)
pid = os.fork()
if pid == 0:
print("current ident", threading.get_ident() == ident)
main = threading.main_thread()
print("main", main.name, type(main).__name__)
print("main ident", main.ident == ident)
print("current is main", threading.current_thread() is main)
# stdout is fully buffered because not a tty,
# we have to flush before exit.
sys.stdout.flush()
else:
assert ws[0].category == DeprecationWarning, ws[0]
assert 'fork' in str(ws[0].message), ws[0]
support.wait_process(pid, exitcode=0)
th = threading.Thread(target=func)
th.start()
th.join()
"""
_, out, err = assert_python_ok("-c", code)
data = out.decode().replace('\r', '')
self.assertEqual(err.decode('utf-8'), "")
self.assertEqual(data,
"current ident True\n"
"main Thread-1 (func) Thread\n"
"main ident True\n"
"current is main True\n"
)
@skip_unless_reliable_fork
@unittest.skipUnless(hasattr(os, 'waitpid'), "test needs os.waitpid()")
def test_main_thread_after_fork_from_foreign_thread(self, create_dummy=False):
code = """if 1:
import os, threading, sys, traceback, _thread
from test import support
def func(lock):
ident = threading.get_ident()
if %s:
# call current_thread() before fork to allocate DummyThread
current = threading.current_thread()
print("current", current.name, type(current).__name__)
print("ident in _active", ident in threading._active)
# flush before fork, so child won't flush it again
sys.stdout.flush()
pid = os.fork()
if pid == 0:
print("current ident", threading.get_ident() == ident)
main = threading.main_thread()
print("main", main.name, type(main).__name__)
print("main ident", main.ident == ident)
print("current is main", threading.current_thread() is main)
print("_dangling", [t.name for t in list(threading._dangling)])
# stdout is fully buffered because not a tty,
# we have to flush before exit.
sys.stdout.flush()
try:
threading._shutdown()
os._exit(0)
except:
traceback.print_exc()
sys.stderr.flush()
os._exit(1)
else:
try:
support.wait_process(pid, exitcode=0)
except Exception:
# avoid 'could not acquire lock for
# <_io.BufferedWriter name='<stderr>'> at interpreter shutdown,'
traceback.print_exc()
sys.stderr.flush()
finally:
lock.release()
join_lock = _thread.allocate_lock()
join_lock.acquire()
th = _thread.start_new_thread(func, (join_lock,))
join_lock.acquire()
""" % create_dummy
# "DeprecationWarning: This process is multi-threaded, use of fork()
# may lead to deadlocks in the child"
_, out, err = assert_python_ok("-W", "ignore::DeprecationWarning", "-c", code)
data = out.decode().replace('\r', '')
self.assertEqual(err.decode(), "")
self.assertEqual(data,
("current Dummy-1 _DummyThread\n" if create_dummy else "") +
f"ident in _active {create_dummy!s}\n" +
"current ident True\n"
"main MainThread _MainThread\n"
"main ident True\n"
"current is main True\n"
"_dangling ['MainThread']\n")
def test_main_thread_after_fork_from_dummy_thread(self, create_dummy=False):
self.test_main_thread_after_fork_from_foreign_thread(create_dummy=True)
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_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):
_testcapi = import_module("_testcapi")
# 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
_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)
threading.settrace(old_trace)
def test_gettrace(self):
def noop_trace(frame, event, arg):
# no operation
return noop_trace
old_trace = threading.gettrace()
try:
threading.settrace(noop_trace)
trace_func = threading.gettrace()
self.assertEqual(noop_trace,trace_func)
finally:
threading.settrace(old_trace)
def test_gettrace_all_threads(self):
def fn(*args): pass
old_trace = threading.gettrace()
first_check = threading.Event()
second_check = threading.Event()
trace_funcs = []
def checker():
trace_funcs.append(sys.gettrace())
first_check.set()
second_check.wait()
trace_funcs.append(sys.gettrace())
try:
t = threading.Thread(target=checker)
t.start()
first_check.wait()
threading.settrace_all_threads(fn)
second_check.set()
t.join()
self.assertEqual(trace_funcs, [None, fn])
self.assertEqual(threading.gettrace(), fn)
self.assertEqual(sys.gettrace(), fn)
finally:
threading.settrace_all_threads(old_trace)
self.assertEqual(threading.gettrace(), old_trace)
self.assertEqual(sys.gettrace(), old_trace)
def test_getprofile(self):
def fn(*args): pass
old_profile = threading.getprofile()
try:
threading.setprofile(fn)
self.assertEqual(fn, threading.getprofile())
finally:
threading.setprofile(old_profile)
def test_getprofile_all_threads(self):
def fn(*args): pass
old_profile = threading.getprofile()
first_check = threading.Event()
second_check = threading.Event()
profile_funcs = []
def checker():
profile_funcs.append(sys.getprofile())
first_check.set()
second_check.wait()
profile_funcs.append(sys.getprofile())
try:
t = threading.Thread(target=checker)
t.start()
first_check.wait()
threading.setprofile_all_threads(fn)
second_check.set()
t.join()
self.assertEqual(profile_funcs, [None, fn])
self.assertEqual(threading.getprofile(), fn)
self.assertEqual(sys.getprofile(), fn)
finally:
threading.setprofile_all_threads(old_profile)
self.assertEqual(threading.getprofile(), old_profile)
self.assertEqual(sys.getprofile(), old_profile)
def test_locals_at_exit(self):
# bpo-19466: thread locals must not be deleted before destructors
# are called
rc, out, err = assert_python_ok("-c", """if 1:
import threading
class Atexit:
def __del__(self):
print("thread_dict.atexit = %r" % thread_dict.atexit)
thread_dict = threading.local()
thread_dict.atexit = "value"
atexit = Atexit()
""")
self.assertEqual(out.rstrip(), b"thread_dict.atexit = 'value'")
def test_boolean_target(self):
# bpo-41149: A thread that had a boolean value of False would not
# run, regardless of whether it was callable. The correct behaviour
# is for a thread to do nothing if its target is None, and to call
# the target otherwise.
class BooleanTarget(object):
def __init__(self):
self.ran = False
def __bool__(self):
return False
def __call__(self):
self.ran = True
target = BooleanTarget()
thread = threading.Thread(target=target)
thread.start()
thread.join()
self.assertTrue(target.ran)
def test_leak_without_join(self):
# bpo-37788: Test that a thread which is not joined explicitly
# does not leak. Test written for reference leak checks.
def noop(): pass
with threading_helper.wait_threads_exit():
threading.Thread(target=noop).start()
# Thread.join() is not called
def test_import_from_another_thread(self):
# bpo-1596321: If the threading module is first import from a thread
# different than the main thread, threading._shutdown() must handle
# this case without logging an error at Python exit.
code = textwrap.dedent('''
import _thread
import sys
event = _thread.allocate_lock()
event.acquire()
def import_threading():
import threading
event.release()
if 'threading' in sys.modules:
raise Exception('threading is already imported')
_thread.start_new_thread(import_threading, ())
# wait until the threading module is imported
event.acquire()
event.release()
if 'threading' not in sys.modules:
raise Exception('threading is not imported')
# don't wait until the thread completes
''')
rc, out, err = assert_python_ok("-c", code)
self.assertEqual(out, b'')
self.assertEqual(err, b'')
def test_start_new_thread_at_finalization(self):
code = """if 1:
import _thread
def f():
print("shouldn't be printed")
class AtFinalization:
def __del__(self):
print("OK")
_thread.start_new_thread(f, ())
at_finalization = AtFinalization()
"""
_, out, err = assert_python_ok("-c", code)
self.assertEqual(out.strip(), b"OK")
self.assertIn(b"can't create new thread at interpreter shutdown", err)
def test_start_new_thread_failed(self):
# gh-109746: if Python fails to start newly created thread
# due to failure of underlying PyThread_start_new_thread() call,
# its state should be removed from interpreter' thread states list
# to avoid its double cleanup
try:
from resource import setrlimit, RLIMIT_NPROC
except ImportError as err:
self.skipTest(err) # RLIMIT_NPROC is specific to Linux and BSD
code = """if 1:
import resource
import _thread
def f():
print("shouldn't be printed")
limits = resource.getrlimit(resource.RLIMIT_NPROC)
[_, hard] = limits
resource.setrlimit(resource.RLIMIT_NPROC, (0, hard))
try:
_thread.start_new_thread(f, ())
except RuntimeError:
print('ok')
else:
print('!skip!')
"""
_, out, err = assert_python_ok("-u", "-c", code)
out = out.strip()
if b'!skip!' in out:
self.skipTest('RLIMIT_NPROC had no effect; probably superuser')
self.assertEqual(out, b'ok')
self.assertEqual(err, b'')
@cpython_only
def test_finalize_daemon_thread_hang(self):
if support.check_sanitizer(thread=True, memory=True):
# the thread running `time.sleep(100)` below will still be alive
# at process exit
self.skipTest(
"https://github.com/python/cpython/issues/124878 - Known"
" race condition that TSAN identifies.")
# gh-87135: tests that daemon threads hang during finalization
script = textwrap.dedent('''
import os
import sys
import threading
import time
import _testcapi
lock = threading.Lock()
lock.acquire()
thread_started_event = threading.Event()
def thread_func():
try:
thread_started_event.set()
_testcapi.finalize_thread_hang(lock.acquire)
finally:
# Control must not reach here.
os._exit(2)
t = threading.Thread(target=thread_func)
t.daemon = True
t.start()
thread_started_event.wait()
# Sleep to ensure daemon thread is blocked on `lock.acquire`
#
# Note: This test is designed so that in the unlikely case that
# `0.1` seconds is not sufficient time for the thread to become
# blocked on `lock.acquire`, the test will still pass, it just
# won't be properly testing the thread behavior during
# finalization.
time.sleep(0.1)
def run_during_finalization():
# Wake up daemon thread
lock.release()
# Sleep to give the daemon thread time to crash if it is going
# to.
#
# Note: If due to an exceptionally slow execution this delay is
# insufficient, the test will still pass but will simply be
# ineffective as a test.
time.sleep(0.1)
# If control reaches here, the test succeeded.
os._exit(0)
# Replace sys.stderr.flush as a way to run code during finalization
orig_flush = sys.stderr.flush
def do_flush(*args, **kwargs):
orig_flush(*args, **kwargs)
if not sys.is_finalizing:
return
sys.stderr.flush = orig_flush
run_during_finalization()
sys.stderr.flush = do_flush
# If the follow exit code is retained, `run_during_finalization`
# did not run.
sys.exit(1)
''')
assert_python_ok("-c", script)
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)
@skip_unless_reliable_fork
def test_2_join_in_forked_process(self):
# Like the test above, but from a forked interpreter
script = """if 1:
from test import support
childpid = os.fork()
if childpid != 0:
# parent process
support.wait_process(childpid, exitcode=0)
sys.exit(0)
# child process
t = threading.Thread(target=joiningfunc,
args=(threading.current_thread(),))
t.start()
print('end of main')
"""
self._run_and_join(script)
@skip_unless_reliable_fork
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:
from test import support
main_thread = threading.current_thread()
def worker():
childpid = os.fork()
if childpid != 0:
# parent process
support.wait_process(childpid, exitcode=0)
sys.exit(0)
# child process
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.
if support.check_sanitizer(thread=True):
# some of the threads running `random_io` below will still be alive
# at process exit
self.skipTest("TSAN would report thread leak")
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.'''
import test.test_threading as mod
while True:
with open(mod.__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)
def test_thread_from_thread(self):
script = """if True:
import threading
import time
def thread2():
time.sleep(0.05)
print("OK")
def thread1():
time.sleep(0.05)
t2 = threading.Thread(target=thread2)
t2.start()
t = threading.Thread(target=thread1)
t.start()
# do not join() -- the interpreter waits for non-daemon threads to
# finish.
"""
rc, out, err = assert_python_ok('-c', script)
self.assertEqual(err, b"")
self.assertEqual(out.strip(), b"OK")
self.assertEqual(rc, 0)
@skip_unless_reliable_fork
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:
support.wait_process(pid, exitcode=50)
else:
os._exit(50)
# Ignore the warning about fork with threads.
with warnings.catch_warnings(category=DeprecationWarning,
action="ignore"):
# 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()
@skip_unless_reliable_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()
try:
# Ignore the warning about fork with threads.
with warnings.catch_warnings(category=DeprecationWarning,
action="ignore"):
pid = os.fork()
if pid == 0:
# check that threads states have been cleared
if len(sys._current_frames()) == 1:
os._exit(51)
else:
os._exit(52)
else:
support.wait_process(pid, exitcode=51)
finally:
for t in threads:
t.join()
class SubinterpThreadingTests(BaseTestCase):
def pipe(self):
r, w = os.pipe()
self.addCleanup(os.close, r)
self.addCleanup(os.close, w)
if hasattr(os, 'set_blocking'):
os.set_blocking(r, False)
return (r, w)
def test_threads_join(self):
# Non-daemon threads should be joined at subinterpreter shutdown
# (issue #18808)
r, w = self.pipe()
code = textwrap.dedent(r"""
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 = self.pipe()
code = textwrap.dedent(r"""
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")
@requires_subinterpreters
def test_threads_join_with_no_main(self):
r_interp, w_interp = self.pipe()
INTERP = b'I'
FINI = b'F'
DONE = b'D'
interp = interpreters.create()
interp.exec(f"""if True:
import os
import threading
import time
done = False
def notify_fini():
global done
done = True
os.write({w_interp}, {FINI!r})
t.join()
threading._register_atexit(notify_fini)
def task():
while not done:
time.sleep(0.1)
os.write({w_interp}, {DONE!r})
t = threading.Thread(target=task)
t.start()
os.write({w_interp}, {INTERP!r})
""")
interp.close()
self.assertEqual(os.read(r_interp, 1), INTERP)
self.assertEqual(os.read(r_interp, 1), FINI)
self.assertEqual(os.read(r_interp, 1), DONE)
@cpython_only
def test_daemon_threads_fatal_error(self):
import_module("_testcapi")
subinterp_code = f"""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({test.support.SHORT_TIMEOUT})
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())
def _check_allowed(self, before_start='', *,
allowed=True,
daemon_allowed=True,
daemon=False,
):
import_module("_testinternalcapi")
subinterp_code = textwrap.dedent(f"""
import test.support
import threading
def func():
print('this should not have run!')
t = threading.Thread(target=func, daemon={daemon})
{before_start}
t.start()
""")
check_multi_interp_extensions = bool(support.Py_GIL_DISABLED)
script = textwrap.dedent(f"""
import test.support
test.support.run_in_subinterp_with_config(
{subinterp_code!r},
use_main_obmalloc=True,
allow_fork=True,
allow_exec=True,
allow_threads={allowed},
allow_daemon_threads={daemon_allowed},
check_multi_interp_extensions={check_multi_interp_extensions},
own_gil=False,
)
""")
with test.support.SuppressCrashReport():
_, _, err = assert_python_ok("-c", script)
return err.decode()
@cpython_only
def test_threads_not_allowed(self):
err = self._check_allowed(
allowed=False,
daemon_allowed=False,
daemon=False,
)
self.assertIn('RuntimeError', err)
@cpython_only
def test_daemon_threads_not_allowed(self):
with self.subTest('via Thread()'):
err = self._check_allowed(
allowed=True,
daemon_allowed=False,
daemon=True,
)
self.assertIn('RuntimeError', err)
with self.subTest('via Thread.daemon setter'):
err = self._check_allowed(
't.daemon = True',
allowed=True,
daemon_allowed=False,
daemon=False,
)
self.assertIn('RuntimeError', err)
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)
@requires_subprocess()
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)
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_print_exception_gh_102056(self):
# This used to crash. See gh-102056.
script = r"""if True:
import time
import threading
import _thread
def f():
try:
f()
except RecursionError:
f()
def g():
try:
raise ValueError()
except* ValueError:
f()
def h():
time.sleep(1)
_thread.interrupt_main()
t = threading.Thread(target=h)
t.start()
g()
t.join()
"""
assert_python_failure("-c", script)
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
def test_multithread_modify_file_noerror(self):
# See issue25872
def modify_file():
with open(os_helper.TESTFN, 'w', encoding='utf-8') as fp:
fp.write(' ')
traceback.format_stack()
self.addCleanup(os_helper.unlink, os_helper.TESTFN)
threads = [
threading.Thread(target=modify_file)
for i in range(100)
]
for t in threads:
t.start()
t.join()
class ThreadRunFail(threading.Thread):
def run(self):
raise ValueError("run failed")
class ExceptHookTests(BaseTestCase):
def setUp(self):
restore_default_excepthook(self)
super().setUp()
@force_not_colorized
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
@force_not_colorized
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')
def test_original_excepthook(self):
def run_thread():
with support.captured_output("stderr") as output:
thread = ThreadRunFail(name="excepthook thread")
thread.start()
thread.join()
return output.getvalue()
def threading_hook(args):
print("Running a thread failed", file=sys.stderr)
default_output = run_thread()
with support.swap_attr(threading, 'excepthook', threading_hook):
custom_hook_output = run_thread()
threading.excepthook = threading.__excepthook__
recovered_output = run_thread()
self.assertEqual(default_output, recovered_output)
self.assertNotEqual(default_output, custom_hook_output)
self.assertEqual(custom_hook_output, "Running a thread failed\n")
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)
def test_signature(self): # gh-102029
with warnings.catch_warnings(record=True) as warnings_log:
threading.RLock()
self.assertEqual(warnings_log, [])
arg_types = [
((1,), {}),
((), {'a': 1}),
((1, 2), {'a': 1}),
]
for args, kwargs in arg_types:
with self.subTest(args=args, kwargs=kwargs):
with self.assertWarns(DeprecationWarning):
threading.RLock(*args, **kwargs)
# Subtypes with custom `__init__` are allowed (but, not recommended):
class CustomRLock(self.locktype):
def __init__(self, a, *, b) -> None:
super().__init__()
with warnings.catch_warnings(record=True) as warnings_log:
CustomRLock(1, b=2)
self.assertEqual(warnings_log, [])
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)
def test_recursion_count(self):
self.skipTest("Condition does not expose _recursion_count()")
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):
restore_default_excepthook(self)
extra = {"ThreadError"}
not_exported = {'currentThread', 'activeCount'}
support.check__all__(self, threading, ('threading', '_thread'),
extra=extra, not_exported=not_exported)
class InterruptMainTests(unittest.TestCase):
def check_interrupt_main_with_signal_handler(self, signum):
def handler(signum, frame):
1/0
old_handler = signal.signal(signum, handler)
self.addCleanup(signal.signal, signum, old_handler)
with self.assertRaises(ZeroDivisionError):
_thread.interrupt_main()
def check_interrupt_main_noerror(self, signum):
handler = signal.getsignal(signum)
try:
# No exception should arise.
signal.signal(signum, signal.SIG_IGN)
_thread.interrupt_main(signum)
signal.signal(signum, signal.SIG_DFL)
_thread.interrupt_main(signum)
finally:
# Restore original handler
signal.signal(signum, handler)
@requires_gil_enabled("gh-118433: Flaky due to a longstanding bug")
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_with_signal_handler(self):
self.check_interrupt_main_with_signal_handler(signal.SIGINT)
self.check_interrupt_main_with_signal_handler(signal.SIGTERM)
def test_interrupt_main_noerror(self):
self.check_interrupt_main_noerror(signal.SIGINT)
self.check_interrupt_main_noerror(signal.SIGTERM)
def test_interrupt_main_invalid_signal(self):
self.assertRaises(ValueError, _thread.interrupt_main, -1)
self.assertRaises(ValueError, _thread.interrupt_main, signal.NSIG)
self.assertRaises(ValueError, _thread.interrupt_main, 1000000)
@threading_helper.reap_threads
def test_can_interrupt_tight_loops(self):
cont = [True]
started = [False]
interrupted = [False]
def worker(started, cont, interrupted):
iterations = 100_000_000
started[0] = True
while cont[0]:
if iterations:
iterations -= 1
else:
return
pass
interrupted[0] = True
t = threading.Thread(target=worker,args=(started, cont, interrupted))
t.start()
while not started[0]:
pass
cont[0] = False
t.join()
self.assertTrue(interrupted[0])
class AtexitTests(unittest.TestCase):
def test_atexit_output(self):
rc, out, err = assert_python_ok("-c", """if True:
import threading
def run_last():
print('parrot')
threading._register_atexit(run_last)
""")
self.assertFalse(err)
self.assertEqual(out.strip(), b'parrot')
def test_atexit_called_once(self):
rc, out, err = assert_python_ok("-c", """if True:
import threading
from unittest.mock import Mock
mock = Mock()
threading._register_atexit(mock)
mock.assert_not_called()
# force early shutdown to ensure it was called once
threading._shutdown()
mock.assert_called_once()
""")
self.assertFalse(err)
def test_atexit_after_shutdown(self):
# The only way to do this is by registering an atexit within
# an atexit, which is intended to raise an exception.
rc, out, err = assert_python_ok("-c", """if True:
import threading
def func():
pass
def run_last():
threading._register_atexit(func)
threading._register_atexit(run_last)
""")
self.assertTrue(err)
self.assertIn("RuntimeError: can't register atexit after shutdown",
err.decode())
if __name__ == "__main__":
unittest.main()
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