# Very rudimentary test of threading module | |
import test.test_support | |
from test.test_support import verbose | |
import random | |
import re | |
import sys | |
thread = test.test_support.import_module('thread') | |
threading = test.test_support.import_module('threading') | |
import time | |
import unittest | |
import weakref | |
import os | |
import subprocess | |
from test import lock_tests | |
# 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.assertTrue(self.nrunning.get() <= 3) | |
time.sleep(delay) | |
if verbose: | |
print 'task', self.name, 'done' | |
with self.mutex: | |
self.nrunning.dec() | |
self.testcase.assertTrue(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.test_support.threading_setup() | |
def tearDown(self): | |
test.test_support.threading_cleanup(*self._threads) | |
test.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.assertEqual(t.ident, None) | |
self.assertTrue(re.match('<TestThread\(.*, initial\)>', repr(t))) | |
t.start() | |
if verbose: | |
print 'waiting for all tasks to complete' | |
for t in threads: | |
t.join(NUMTASKS) | |
self.assertTrue(not t.is_alive()) | |
self.assertNotEqual(t.ident, 0) | |
self.assertFalse(t.ident is None) | |
self.assertTrue(re.match('<TestThread\(.*, \w+ -?\d+\)>', repr(t))) | |
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.assertFalse(threading.currentThread().ident is None) | |
def f(): | |
ident.append(threading.currentThread().ident) | |
done.set() | |
done = threading.Event() | |
ident = [] | |
thread.start_new_thread(f, ()) | |
done.wait() | |
self.assertFalse(ident[0] is None) | |
# Kill the "immortal" _DummyThread | |
del threading._active[ident[0]] | |
# run with a small(ish) thread stack size (256kB) | |
def test_various_ops_small_stack(self): | |
if verbose: | |
print 'with 256kB thread stack size...' | |
try: | |
threading.stack_size(262144) | |
except thread.error: | |
if verbose: | |
print 'platform does not support changing thread stack size' | |
return | |
self.test_various_ops() | |
threading.stack_size(0) | |
# run with a large thread stack size (1MB) | |
def test_various_ops_large_stack(self): | |
if verbose: | |
print 'with 1MB thread stack size...' | |
try: | |
threading.stack_size(0x100000) | |
except thread.error: | |
if verbose: | |
print 'platform does not support changing thread stack size' | |
return | |
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() | |
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) | |
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): | |
try: | |
import ctypes | |
except ImportError: | |
if verbose: | |
print "test_PyThreadState_SetAsyncExc can't import ctypes" | |
return # can't do anything | |
set_async_exc = ctypes.pythonapi.PyThreadState_SetAsyncExc | |
class AsyncExc(Exception): | |
pass | |
exception = ctypes.py_object(AsyncExc) | |
# First check it works when setting the exception from the same thread. | |
tid = thread.get_ident() | |
try: | |
result = set_async_exc(ctypes.c_long(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 = thread.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(ctypes.c_long(-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.assertTrue(not t.finished) | |
if verbose: | |
print " attempting to raise asynch exception in worker" | |
result = set_async_exc(ctypes.c_long(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 thread.error() | |
_start_new_thread = threading._start_new_thread | |
threading._start_new_thread = fail_new_thread | |
try: | |
t = threading.Thread(target=lambda: None) | |
self.assertRaises(thread.error, 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. | |
try: | |
import ctypes | |
except ImportError: | |
if verbose: | |
print("test_finalize_with_runnning_thread can't import ctypes") | |
return # can't do anything | |
rc = subprocess.call([sys.executable, "-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 | |
p = subprocess.Popen([sys.executable, "-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) | |
"""], | |
stdout=subprocess.PIPE, | |
stderr=subprocess.PIPE) | |
self.addCleanup(p.stdout.close) | |
self.addCleanup(p.stderr.close) | |
stdout, stderr = p.communicate() | |
rc = p.returncode | |
self.assertFalse(rc == 2, "interpreted was blocked") | |
self.assertTrue(rc == 0, | |
"Unexpected error: " + repr(stderr)) | |
def test_join_nondaemon_on_shutdown(self): | |
# Issue 1722344 | |
# Raising SystemExit skipped threading._shutdown | |
p = subprocess.Popen([sys.executable, "-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 | |
"""], | |
stdout=subprocess.PIPE, | |
stderr=subprocess.PIPE) | |
self.addCleanup(p.stdout.close) | |
self.addCleanup(p.stderr.close) | |
stdout, stderr = p.communicate() | |
self.assertEqual(stdout.strip(), | |
"Woke up, sleep function is: <built-in function sleep>") | |
stderr = re.sub(r"^\[\d+ refs\]", "", stderr, re.MULTILINE).strip() | |
self.assertEqual(stderr, "") | |
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.getcheckinterval() | |
try: | |
for i in xrange(1, 100): | |
# Try a couple times at each thread-switching interval | |
# to get more interleavings. | |
sys.setcheckinterval(i // 5) | |
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.setcheckinterval(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.assertEqual(None, 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.assertEqual(None, weak_raising_cyclic_object(), | |
msg=('%d references still around' % | |
sys.getrefcount(weak_raising_cyclic_object()))) | |
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' | |
\n""" + script | |
p = subprocess.Popen([sys.executable, "-c", script], stdout=subprocess.PIPE) | |
rc = p.wait() | |
data = p.stdout.read().replace('\r', '') | |
p.stdout.close() | |
self.assertEqual(data, "end of main\nend of thread\n") | |
self.assertFalse(rc == 2, "interpreter was blocked") | |
self.assertTrue(rc == 0, "Unexpected error") | |
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) | |
def test_2_join_in_forked_process(self): | |
# Like the test above, but from a forked interpreter | |
import os | |
if not hasattr(os, 'fork'): | |
return | |
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) | |
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. | |
import os | |
if not hasattr(os, 'fork'): | |
return | |
# Skip platforms with known problems forking from a worker thread. | |
# See http://bugs.python.org/issue3863. | |
if sys.platform in ('freebsd4', 'freebsd5', 'freebsd6', 'netbsd5', | |
'os2emx'): | |
print >>sys.stderr, ('Skipping test_3_join_in_forked_from_thread' | |
' due to known OS bugs on'), sys.platform | |
return | |
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) | |
def assertScriptHasOutput(self, script, expected_output): | |
p = subprocess.Popen([sys.executable, "-c", script], | |
stdout=subprocess.PIPE) | |
rc = p.wait() | |
data = p.stdout.read().decode().replace('\r', '') | |
self.assertEqual(rc, 0, "Unexpected error") | |
self.assertEqual(data, expected_output) | |
@unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()") | |
def test_4_joining_across_fork_in_worker_thread(self): | |
# There used to be a possible deadlock when forking from a child | |
# thread. See http://bugs.python.org/issue6643. | |
# Skip platforms with known problems forking from a worker thread. | |
# See http://bugs.python.org/issue3863. | |
if sys.platform in ('freebsd4', 'freebsd5', 'freebsd6', 'os2emx'): | |
raise unittest.SkipTest('due to known OS bugs on ' + sys.platform) | |
# The script takes the following steps: | |
# - The main thread in the parent process starts a new thread and then | |
# tries to join it. | |
# - The join operation acquires the Lock inside the thread's _block | |
# Condition. (See threading.py:Thread.join().) | |
# - We stub out the acquire method on the condition to force it to wait | |
# until the child thread forks. (See LOCK ACQUIRED HERE) | |
# - The child thread forks. (See LOCK HELD and WORKER THREAD FORKS | |
# HERE) | |
# - The main thread of the parent process enters Condition.wait(), | |
# which releases the lock on the child thread. | |
# - The child process returns. Without the necessary fix, when the | |
# main thread of the child process (which used to be the child thread | |
# in the parent process) attempts to exit, it will try to acquire the | |
# lock in the Thread._block Condition object and hang, because the | |
# lock was held across the fork. | |
script = """if 1: | |
import os, time, threading | |
finish_join = False | |
start_fork = False | |
def worker(): | |
# Wait until this thread's lock is acquired before forking to | |
# create the deadlock. | |
global finish_join | |
while not start_fork: | |
time.sleep(0.01) | |
# LOCK HELD: Main thread holds lock across this call. | |
childpid = os.fork() | |
finish_join = True | |
if childpid != 0: | |
# Parent process just waits for child. | |
os.waitpid(childpid, 0) | |
# Child process should just return. | |
w = threading.Thread(target=worker) | |
# Stub out the private condition variable's lock acquire method. | |
# This acquires the lock and then waits until the child has forked | |
# before returning, which will release the lock soon after. If | |
# someone else tries to fix this test case by acquiring this lock | |
# before forking instead of resetting it, the test case will | |
# deadlock when it shouldn't. | |
condition = w._block | |
orig_acquire = condition.acquire | |
call_count_lock = threading.Lock() | |
call_count = 0 | |
def my_acquire(): | |
global call_count | |
global start_fork | |
orig_acquire() # LOCK ACQUIRED HERE | |
start_fork = True | |
if call_count == 0: | |
while not finish_join: | |
time.sleep(0.01) # WORKER THREAD FORKS HERE | |
with call_count_lock: | |
call_count += 1 | |
condition.acquire = my_acquire | |
w.start() | |
w.join() | |
print('end of main') | |
""" | |
self.assertScriptHasOutput(script, "end of main\n") | |
@unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()") | |
def test_5_clear_waiter_locks_to_avoid_crash(self): | |
# Check that a spawned thread that forks doesn't segfault on certain | |
# platforms, namely OS X. This used to happen if there was a waiter | |
# lock in the thread's condition variable's waiters list. Even though | |
# we know the lock will be held across the fork, it is not safe to | |
# release locks held across forks on all platforms, so releasing the | |
# waiter lock caused a segfault on OS X. Furthermore, since locks on | |
# OS X are (as of this writing) implemented with a mutex + condition | |
# variable instead of a semaphore, while we know that the Python-level | |
# lock will be acquired, we can't know if the internal mutex will be | |
# acquired at the time of the fork. | |
# Skip platforms with known problems forking from a worker thread. | |
# See http://bugs.python.org/issue3863. | |
if sys.platform in ('freebsd4', 'freebsd5', 'freebsd6', 'os2emx'): | |
raise unittest.SkipTest('due to known OS bugs on ' + sys.platform) | |
script = """if True: | |
import os, time, threading | |
start_fork = False | |
def worker(): | |
# Wait until the main thread has attempted to join this thread | |
# before continuing. | |
while not start_fork: | |
time.sleep(0.01) | |
childpid = os.fork() | |
if childpid != 0: | |
# Parent process just waits for child. | |
(cpid, rc) = os.waitpid(childpid, 0) | |
assert cpid == childpid | |
assert rc == 0 | |
print('end of worker thread') | |
else: | |
# Child process should just return. | |
pass | |
w = threading.Thread(target=worker) | |
# Stub out the private condition variable's _release_save method. | |
# This releases the condition's lock and flips the global that | |
# causes the worker to fork. At this point, the problematic waiter | |
# lock has been acquired once by the waiter and has been put onto | |
# the waiters list. | |
condition = w._block | |
orig_release_save = condition._release_save | |
def my_release_save(): | |
global start_fork | |
orig_release_save() | |
# Waiter lock held here, condition lock released. | |
start_fork = True | |
condition._release_save = my_release_save | |
w.start() | |
w.join() | |
print('end of main thread') | |
""" | |
output = "end of worker thread\nend of main thread\n" | |
self.assertScriptHasOutput(script, output) | |
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) | |
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) | |
class LockTests(lock_tests.LockTests): | |
locktype = staticmethod(threading.Lock) | |
class RLockTests(lock_tests.RLockTests): | |
locktype = staticmethod(threading.RLock) | |
class EventTests(lock_tests.EventTests): | |
eventtype = staticmethod(threading.Event) | |
class ConditionAsRLockTests(lock_tests.RLockTests): | |
# An 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) | |
@unittest.skipUnless(sys.platform == 'darwin', 'test macosx problem') | |
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 RuntimeError: | |
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) | |
stdout, stderr = p.communicate() | |
data = stdout.decode().replace('\r', '') | |
self.assertEqual(p.returncode, 0, "Unexpected error") | |
self.assertEqual(data, expected_output) | |
def test_main(): | |
test.test_support.run_unittest(LockTests, RLockTests, EventTests, | |
ConditionAsRLockTests, ConditionTests, | |
SemaphoreTests, BoundedSemaphoreTests, | |
ThreadTests, | |
ThreadJoinOnShutdown, | |
ThreadingExceptionTests, | |
) | |
if __name__ == "__main__": | |
test_main() |