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 wait_threads_exit(timeout=None):
"""
bpo-31234: Context manager to wait until all threads created in the with
statement exit.
Use _thread.count() to check if threads exited. Indirectly, wait until
threads exit the internal t_bootstrap() C function of the _thread module.
threading_setup() and threading_cleanup() are designed to emit a warning
if a test leaves running threads in the background. This context manager
is designed to cleanup threads started by the _thread.start_new_thread()
which doesn't allow to wait for thread exit, whereas thread.Thread has a
join() method.
"""
if timeout is None:
timeout = support.SHORT_TIMEOUT
old_count = _thread._count()
try:
yield
finally:
start_time = time.monotonic()
for _ in support.sleeping_retry(timeout, error=False):
support.gc_collect()
count = _thread._count()
if count <= old_count:
break
else:
dt = time.monotonic() - start_time
msg = (f"wait_threads() failed to cleanup {count - old_count} "
f"threads after {dt:.1f} seconds "
f"(count: {count}, old count: {old_count})")
raise AssertionError(msg)
def test_wait(self):
for i in range(NUM_THREADS):
thread = threading.Thread(target=self.f, args=(i, ))
thread.start()
self.threads.append(thread)
# busy-loop to wait for threads
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
if len(self.alive) >= NUM_THREADS:
break
a = sorted(self.alive.keys())
self.assertEqual(a, list(range(NUM_THREADS)))
prefork_lives = self.alive.copy()
if sys.platform in ['unixware7']:
cpid = os.fork1()
else:
cpid = os.fork()
if cpid == 0:
# Child
time.sleep(LONGSLEEP)
n = 0
for key in self.alive:
if self.alive[key] != prefork_lives[key]:
n += 1
os._exit(n)
else:
# Parent
self.wait_impl(cpid, exitcode=0)
def _lock(self, lock_func, lock_name):
self.addCleanup(os_helper.unlink, os_helper.TESTFN)
code = '\n'.join(("import fcntl, time",
"with open('%s', 'wb') as f:" % os_helper.TESTFN,
" fcntl.%s(f, fcntl.LOCK_EX)" % lock_name,
" time.sleep(%s)" % self.sleep_time))
start_time = time.monotonic()
proc = self.subprocess(code)
with kill_on_error(proc):
with open(os_helper.TESTFN, 'wb') as f:
# synchronize the subprocess
start_time = time.monotonic()
for _ in support.sleeping_retry(support.LONG_TIMEOUT,
error=False):
try:
lock_func(f, fcntl.LOCK_EX | fcntl.LOCK_NB)
lock_func(f, fcntl.LOCK_UN)
except BlockingIOError:
break
else:
dt = time.monotonic() - start_time
raise Exception("failed to sync child in %.1f sec" % dt)
# the child locked the file just a moment ago for 'sleep_time' seconds
# that means that the lock below will block for 'sleep_time' minus some
# potential context switch delay
lock_func(f, fcntl.LOCK_EX)
dt = time.monotonic() - start_time
self.assertGreaterEqual(dt, self.sleep_time)
self.stop_alarm()
proc.wait()
def wait_impl(self, cpid, *, exitcode):
# This many iterations can be required, since some previously run
# tests (e.g. test_ctypes) could have spawned a lot of children
# very quickly.
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
# wait3() shouldn't hang, but some of the buildbots seem to hang
# in the forking tests. This is an attempt to fix the problem.
spid, status, rusage = os.wait3(os.WNOHANG)
if spid == cpid:
break
self.assertEqual(spid, cpid)
self.assertEqual(os.waitstatus_to_exitcode(status), exitcode)
self.assertTrue(rusage)
def wait_impl(self, cpid, *, exitcode):
option = os.WNOHANG
if sys.platform.startswith('aix'):
# Issue #11185: wait4 is broken on AIX and will always return 0
# with WNOHANG.
option = 0
for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
# wait4() shouldn't hang, but some of the buildbots seem to hang
# in the forking tests. This is an attempt to fix the problem.
spid, status, rusage = os.wait4(cpid, option)
if spid == cpid:
break
self.assertEqual(spid, cpid)
self.assertEqual(os.waitstatus_to_exitcode(status), exitcode)
self.assertTrue(rusage)