import os
import unittest
import random
from test import support
from test.support import threading_helper
import _thread as thread
import time
import warnings
import weakref
from test import lock_tests
threading_helper.requires_working_threading(module=True)
NUMTASKS = 10
NUMTRIPS = 3
_print_mutex = thread.allocate_lock()
def verbose_print(arg):
"""Helper function for printing out debugging output."""
if support.verbose:
with _print_mutex:
print(arg)
class BasicThreadTest(unittest.TestCase):
def setUp(self):
self.done_mutex = thread.allocate_lock()
self.done_mutex.acquire()
self.running_mutex = thread.allocate_lock()
self.random_mutex = thread.allocate_lock()
self.created = 0
self.running = 0
self.next_ident = 0
key = threading_helper.threading_setup()
self.addCleanup(threading_helper.threading_cleanup, *key)
class ThreadRunningTests(BasicThreadTest):
def newtask(self):
with self.running_mutex:
self.next_ident += 1
verbose_print("creating task %s" % self.next_ident)
thread.start_new_thread(self.task, (self.next_ident,))
self.created += 1
self.running += 1
def task(self, ident):
with self.random_mutex:
delay = random.random() / 10000.0
verbose_print("task %s will run for %sus" % (ident, round(delay*1e6)))
time.sleep(delay)
verbose_print("task %s done" % ident)
with self.running_mutex:
self.running -= 1
if self.created == NUMTASKS and self.running == 0:
self.done_mutex.release()
def test_starting_threads(self):
with threading_helper.wait_threads_exit():
# Basic test for thread creation.
for i in range(NUMTASKS):
self.newtask()
verbose_print("waiting for tasks to complete...")
self.done_mutex.acquire()
verbose_print("all tasks done")
def test_stack_size(self):
# Various stack size tests.
self.assertEqual(thread.stack_size(), 0, "initial stack size is not 0")
thread.stack_size(0)
self.assertEqual(thread.stack_size(), 0, "stack_size not reset to default")
@unittest.skipIf(os.name not in ("nt", "posix"), 'test meant for nt and posix')
def test_nt_and_posix_stack_size(self):
try:
thread.stack_size(4096)
except ValueError:
verbose_print("caught expected ValueError setting "
"stack_size(4096)")
except thread.error:
self.skipTest("platform does not support changing thread stack "
"size")
fail_msg = "stack_size(%d) failed - should succeed"
for tss in (262144, 0x100000, 0):
thread.stack_size(tss)
self.assertEqual(thread.stack_size(), tss, fail_msg % tss)
verbose_print("successfully set stack_size(%d)" % tss)
for tss in (262144, 0x100000):
verbose_print("trying stack_size = (%d)" % tss)
self.next_ident = 0
self.created = 0
with threading_helper.wait_threads_exit():
for i in range(NUMTASKS):
self.newtask()
verbose_print("waiting for all tasks to complete")
self.done_mutex.acquire()
verbose_print("all tasks done")
thread.stack_size(0)
def test__count(self):
# Test the _count() function.
orig = thread._count()
mut = thread.allocate_lock()
mut.acquire()
started = []
def task():
started.append(None)
mut.acquire()
mut.release()
with threading_helper.wait_threads_exit():
thread.start_new_thread(task, ())
for _ in support.sleeping_retry(support.LONG_TIMEOUT):
if started:
break
self.assertEqual(thread._count(), orig + 1)
# Allow the task to finish.
mut.release()
# The only reliable way to be sure that the thread ended from the
# interpreter's point of view is to wait for the function object to
# be destroyed.
done = []
wr = weakref.ref(task, lambda _: done.append(None))
del task
for _ in support.sleeping_retry(support.LONG_TIMEOUT):
if done:
break
support.gc_collect() # For PyPy or other GCs.
self.assertEqual(thread._count(), orig)
def test_unraisable_exception(self):
def task():
started.release()
raise ValueError("task failed")
started = thread.allocate_lock()
with support.catch_unraisable_exception() as cm:
with threading_helper.wait_threads_exit():
started.acquire()
thread.start_new_thread(task, ())
started.acquire()
self.assertEqual(str(cm.unraisable.exc_value), "task failed")
self.assertIsNone(cm.unraisable.object)
self.assertEqual(cm.unraisable.err_msg,
f"Exception ignored in thread started by {task!r}")
self.assertIsNotNone(cm.unraisable.exc_traceback)
def test_join_thread(self):
finished = []
def task():
time.sleep(0.05)
finished.append(thread.get_ident())
with threading_helper.wait_threads_exit():
handle = thread.start_joinable_thread(task)
handle.join()
self.assertEqual(len(finished), 1)
self.assertEqual(handle.ident, finished[0])
def test_join_thread_already_exited(self):
def task():
pass
with threading_helper.wait_threads_exit():
handle = thread.start_joinable_thread(task)
time.sleep(0.05)
handle.join()
def test_join_several_times(self):
def task():
pass
with threading_helper.wait_threads_exit():
handle = thread.start_joinable_thread(task)
handle.join()
# Subsequent join() calls should succeed
handle.join()
def test_joinable_not_joined(self):
handle_destroyed = thread.allocate_lock()
handle_destroyed.acquire()
def task():
handle_destroyed.acquire()
with threading_helper.wait_threads_exit():
handle = thread.start_joinable_thread(task)
del handle
handle_destroyed.release()
def test_join_from_self(self):
errors = []
handles = []
start_joinable_thread_returned = thread.allocate_lock()
start_joinable_thread_returned.acquire()
task_tried_to_join = thread.allocate_lock()
task_tried_to_join.acquire()
def task():
start_joinable_thread_returned.acquire()
try:
handles[0].join()
except Exception as e:
errors.append(e)
finally:
task_tried_to_join.release()
with threading_helper.wait_threads_exit():
handle = thread.start_joinable_thread(task)
handles.append(handle)
start_joinable_thread_returned.release()
# Can still join after joining failed in other thread
task_tried_to_join.acquire()
handle.join()
assert len(errors) == 1
with self.assertRaisesRegex(RuntimeError, "Cannot join current thread"):
raise errors[0]
def test_join_then_self_join(self):
# make sure we can't deadlock in the following scenario with
# threads t0 and t1 (see comment in `ThreadHandle_join()` for more
# details):
#
# - t0 joins t1
# - t1 self joins
def make_lock():
lock = thread.allocate_lock()
lock.acquire()
return lock
error = None
self_joiner_handle = None
self_joiner_started = make_lock()
self_joiner_barrier = make_lock()
def self_joiner():
nonlocal error
self_joiner_started.release()
self_joiner_barrier.acquire()
try:
self_joiner_handle.join()
except Exception as e:
error = e
joiner_started = make_lock()
def joiner():
joiner_started.release()
self_joiner_handle.join()
with threading_helper.wait_threads_exit():
self_joiner_handle = thread.start_joinable_thread(self_joiner)
# Wait for the self-joining thread to start
self_joiner_started.acquire()
# Start the thread that joins the self-joiner
joiner_handle = thread.start_joinable_thread(joiner)
# Wait for the joiner to start
joiner_started.acquire()
# Not great, but I don't think there's a deterministic way to make
# sure that the self-joining thread has been joined.
time.sleep(0.1)
# Unblock the self-joiner
self_joiner_barrier.release()
self_joiner_handle.join()
joiner_handle.join()
with self.assertRaisesRegex(RuntimeError, "Cannot join current thread"):
raise error
def test_join_with_timeout(self):
lock = thread.allocate_lock()
lock.acquire()
def thr():
lock.acquire()
with threading_helper.wait_threads_exit():
handle = thread.start_joinable_thread(thr)
handle.join(0.1)
self.assertFalse(handle.is_done())
lock.release()
handle.join()
self.assertTrue(handle.is_done())
def test_join_unstarted(self):
handle = thread._ThreadHandle()
with self.assertRaisesRegex(RuntimeError, "thread not started"):
handle.join()
def test_set_done_unstarted(self):
handle = thread._ThreadHandle()
with self.assertRaisesRegex(RuntimeError, "thread not started"):
handle._set_done()
def test_start_duplicate_handle(self):
lock = thread.allocate_lock()
lock.acquire()
def func():
lock.acquire()
handle = thread._ThreadHandle()
with threading_helper.wait_threads_exit():
thread.start_joinable_thread(func, handle=handle)
with self.assertRaisesRegex(RuntimeError, "thread already started"):
thread.start_joinable_thread(func, handle=handle)
lock.release()
handle.join()
def test_start_with_none_handle(self):
def func():
pass
with threading_helper.wait_threads_exit():
handle = thread.start_joinable_thread(func, handle=None)
handle.join()
class Barrier:
def __init__(self, num_threads):
self.num_threads = num_threads
self.waiting = 0
self.checkin_mutex = thread.allocate_lock()
self.checkout_mutex = thread.allocate_lock()
self.checkout_mutex.acquire()
def enter(self):
self.checkin_mutex.acquire()
self.waiting = self.waiting + 1
if self.waiting == self.num_threads:
self.waiting = self.num_threads - 1
self.checkout_mutex.release()
return
self.checkin_mutex.release()
self.checkout_mutex.acquire()
self.waiting = self.waiting - 1
if self.waiting == 0:
self.checkin_mutex.release()
return
self.checkout_mutex.release()
class BarrierTest(BasicThreadTest):
def test_barrier(self):
with threading_helper.wait_threads_exit():
self.bar = Barrier(NUMTASKS)
self.running = NUMTASKS
for i in range(NUMTASKS):
thread.start_new_thread(self.task2, (i,))
verbose_print("waiting for tasks to end")
self.done_mutex.acquire()
verbose_print("tasks done")
def task2(self, ident):
for i in range(NUMTRIPS):
if ident == 0:
# give it a good chance to enter the next
# barrier before the others are all out
# of the current one
delay = 0
else:
with self.random_mutex:
delay = random.random() / 10000.0
verbose_print("task %s will run for %sus" %
(ident, round(delay * 1e6)))
time.sleep(delay)
verbose_print("task %s entering %s" % (ident, i))
self.bar.enter()
verbose_print("task %s leaving barrier" % ident)
with self.running_mutex:
self.running -= 1
# Must release mutex before releasing done, else the main thread can
# exit and set mutex to None as part of global teardown; then
# mutex.release() raises AttributeError.
finished = self.running == 0
if finished:
self.done_mutex.release()
class LockTests(lock_tests.LockTests):
locktype = thread.allocate_lock
class TestForkInThread(unittest.TestCase):
def setUp(self):
self.read_fd, self.write_fd = os.pipe()
@support.requires_fork()
@threading_helper.reap_threads
def test_forkinthread(self):
pid = None
def fork_thread(read_fd, write_fd):
nonlocal pid
# Ignore the warning about fork with threads.
with warnings.catch_warnings(category=DeprecationWarning,
action="ignore"):
# fork in a thread (DANGER, undefined per POSIX)
if (pid := os.fork()):
# parent process
return
# child process
try:
os.close(read_fd)
os.write(write_fd, b"OK")
finally:
os._exit(0)
with threading_helper.wait_threads_exit():
thread.start_new_thread(fork_thread, (self.read_fd, self.write_fd))
self.assertEqual(os.read(self.read_fd, 2), b"OK")
os.close(self.write_fd)
self.assertIsNotNone(pid)
support.wait_process(pid, exitcode=0)
def tearDown(self):
try:
os.close(self.read_fd)
except OSError:
pass
try:
os.close(self.write_fd)
except OSError:
pass
if __name__ == "__main__":
unittest.main()
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