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Merged revisions 76137,76172 via svnmerge from 

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r76137 | antoine.pitrou | 2009-11-06 23:34:35 +0100 (ven., 06 nov. 2009) | 4 lines

  Issue #7270: Add some dedicated unit tests for multi-thread synchronization
  primitives such as Lock, RLock, Condition, Event and Semaphore.
........
  r76172 | antoine.pitrou | 2009-11-09 17:00:11 +0100 (lun., 09 nov. 2009) | 5 lines

  Issue #7282: Fix a memory leak when an RLock was used in a thread other
  than those started through `threading.Thread` (for example, using
  `thread.start_new_thread()`.
........
This commit is contained in:
Antoine Pitrou 2009-11-09 16:47:50 +00:00
parent f4b581ed25
commit c747d3a5d2
5 changed files with 604 additions and 30 deletions
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550
Lib/test/lock_tests.py Normal file
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@ -0,0 +1,550 @@
"""
Various tests for synchronization primitives.
"""
import sys
import time
from thread import start_new_thread, get_ident
import threading
import unittest
from test import test_support as support
def _wait():
# A crude wait/yield function not relying on synchronization primitives.
time.sleep(0.01)
class Bunch(object):
"""
A bunch of threads.
"""
def __init__(self, f, n, wait_before_exit=False):
"""
Construct a bunch of `n` threads running the same function `f`.
If `wait_before_exit` is True, the threads won't terminate until
do_finish() is called.
"""
self.f = f
self.n = n
self.started = []
self.finished = []
self._can_exit = not wait_before_exit
def task():
tid = get_ident()
self.started.append(tid)
try:
f()
finally:
self.finished.append(tid)
while not self._can_exit:
_wait()
for i in range(n):
start_new_thread(task, ())
def wait_for_started(self):
while len(self.started) < self.n:
_wait()
def wait_for_finished(self):
while len(self.finished) < self.n:
_wait()
def do_finish(self):
self._can_exit = True
class BaseTestCase(unittest.TestCase):
def setUp(self):
self._threads = support.threading_setup()
def tearDown(self):
support.threading_cleanup(*self._threads)
support.reap_children()
class BaseLockTests(BaseTestCase):
"""
Tests for both recursive and non-recursive locks.
"""
def test_constructor(self):
lock = self.locktype()
del lock
def test_acquire_destroy(self):
lock = self.locktype()
lock.acquire()
del lock
def test_acquire_release(self):
lock = self.locktype()
lock.acquire()
lock.release()
del lock
def test_try_acquire(self):
lock = self.locktype()
self.assertTrue(lock.acquire(False))
lock.release()
def test_try_acquire_contended(self):
lock = self.locktype()
lock.acquire()
result = []
def f():
result.append(lock.acquire(False))
Bunch(f, 1).wait_for_finished()
self.assertFalse(result[0])
lock.release()
def test_acquire_contended(self):
lock = self.locktype()
lock.acquire()
N = 5
def f():
lock.acquire()
lock.release()
b = Bunch(f, N)
b.wait_for_started()
_wait()
self.assertEqual(len(b.finished), 0)
lock.release()
b.wait_for_finished()
self.assertEqual(len(b.finished), N)
def test_with(self):
lock = self.locktype()
def f():
lock.acquire()
lock.release()
def _with(err=None):
with lock:
if err is not None:
raise err
_with()
# Check the lock is unacquired
Bunch(f, 1).wait_for_finished()
self.assertRaises(TypeError, _with, TypeError)
# Check the lock is unacquired
Bunch(f, 1).wait_for_finished()
def test_thread_leak(self):
# The lock shouldn't leak a Thread instance when used from a foreign
# (non-threading) thread.
lock = self.locktype()
def f():
lock.acquire()
lock.release()
n = len(threading.enumerate())
# We run many threads in the hope that existing threads ids won't
# be recycled.
Bunch(f, 15).wait_for_finished()
self.assertEqual(n, len(threading.enumerate()))
class LockTests(BaseLockTests):
"""
Tests for non-recursive, weak locks
(which can be acquired and released from different threads).
"""
def test_reacquire(self):
# Lock needs to be released before re-acquiring.
lock = self.locktype()
phase = []
def f():
lock.acquire()
phase.append(None)
lock.acquire()
phase.append(None)
start_new_thread(f, ())
while len(phase) == 0:
_wait()
_wait()
self.assertEqual(len(phase), 1)
lock.release()
while len(phase) == 1:
_wait()
self.assertEqual(len(phase), 2)
def test_different_thread(self):
# Lock can be released from a different thread.
lock = self.locktype()
lock.acquire()
def f():
lock.release()
b = Bunch(f, 1)
b.wait_for_finished()
lock.acquire()
lock.release()
class RLockTests(BaseLockTests):
"""
Tests for recursive locks.
"""
def test_reacquire(self):
lock = self.locktype()
lock.acquire()
lock.acquire()
lock.release()
lock.acquire()
lock.release()
lock.release()
def test_release_unacquired(self):
# Cannot release an unacquired lock
lock = self.locktype()
self.assertRaises(RuntimeError, lock.release)
lock.acquire()
lock.acquire()
lock.release()
lock.acquire()
lock.release()
lock.release()
self.assertRaises(RuntimeError, lock.release)
def test_different_thread(self):
# Cannot release from a different thread
lock = self.locktype()
def f():
lock.acquire()
b = Bunch(f, 1, True)
try:
self.assertRaises(RuntimeError, lock.release)
finally:
b.do_finish()
def test__is_owned(self):
lock = self.locktype()
self.assertFalse(lock._is_owned())
lock.acquire()
self.assertTrue(lock._is_owned())
lock.acquire()
self.assertTrue(lock._is_owned())
result = []
def f():
result.append(lock._is_owned())
Bunch(f, 1).wait_for_finished()
self.assertFalse(result[0])
lock.release()
self.assertTrue(lock._is_owned())
lock.release()
self.assertFalse(lock._is_owned())
class EventTests(BaseTestCase):
"""
Tests for Event objects.
"""
def test_is_set(self):
evt = self.eventtype()
self.assertFalse(evt.is_set())
evt.set()
self.assertTrue(evt.is_set())
evt.set()
self.assertTrue(evt.is_set())
evt.clear()
self.assertFalse(evt.is_set())
evt.clear()
self.assertFalse(evt.is_set())
def _check_notify(self, evt):
# All threads get notified
N = 5
results1 = []
results2 = []
def f():
evt.wait()
results1.append(evt.is_set())
evt.wait()
results2.append(evt.is_set())
b = Bunch(f, N)
b.wait_for_started()
_wait()
self.assertEqual(len(results1), 0)
evt.set()
b.wait_for_finished()
self.assertEqual(results1, [True] * N)
self.assertEqual(results2, [True] * N)
def test_notify(self):
evt = self.eventtype()
self._check_notify(evt)
# Another time, after an explicit clear()
evt.set()
evt.clear()
self._check_notify(evt)
def test_timeout(self):
evt = self.eventtype()
results1 = []
results2 = []
N = 5
def f():
evt.wait(0.0)
results1.append(evt.is_set())
t1 = time.time()
evt.wait(0.2)
r = evt.is_set()
t2 = time.time()
results2.append((r, t2 - t1))
Bunch(f, N).wait_for_finished()
self.assertEqual(results1, [False] * N)
for r, dt in results2:
self.assertFalse(r)
self.assertTrue(dt >= 0.2, dt)
# The event is set
results1 = []
results2 = []
evt.set()
Bunch(f, N).wait_for_finished()
self.assertEqual(results1, [True] * N)
for r, dt in results2:
self.assertTrue(r)
class ConditionTests(BaseTestCase):
"""
Tests for condition variables.
"""
def test_acquire(self):
cond = self.condtype()
# Be default we have an RLock: the condition can be acquired multiple
# times.
cond.acquire()
cond.acquire()
cond.release()
cond.release()
lock = threading.Lock()
cond = self.condtype(lock)
cond.acquire()
self.assertFalse(lock.acquire(False))
cond.release()
self.assertTrue(lock.acquire(False))
self.assertFalse(cond.acquire(False))
lock.release()
with cond:
self.assertFalse(lock.acquire(False))
def test_unacquired_wait(self):
cond = self.condtype()
self.assertRaises(RuntimeError, cond.wait)
def test_unacquired_notify(self):
cond = self.condtype()
self.assertRaises(RuntimeError, cond.notify)
def _check_notify(self, cond):
N = 5
results1 = []
results2 = []
phase_num = 0
def f():
cond.acquire()
cond.wait()
cond.release()
results1.append(phase_num)
cond.acquire()
cond.wait()
cond.release()
results2.append(phase_num)
b = Bunch(f, N)
b.wait_for_started()
_wait()
self.assertEqual(results1, [])
# Notify 3 threads at first
cond.acquire()
cond.notify(3)
_wait()
phase_num = 1
cond.release()
while len(results1) < 3:
_wait()
self.assertEqual(results1, [1] * 3)
self.assertEqual(results2, [])
# Notify 5 threads: they might be in their first or second wait
cond.acquire()
cond.notify(5)
_wait()
phase_num = 2
cond.release()
while len(results1) + len(results2) < 8:
_wait()
self.assertEqual(results1, [1] * 3 + [2] * 2)
self.assertEqual(results2, [2] * 3)
# Notify all threads: they are all in their second wait
cond.acquire()
cond.notify_all()
_wait()
phase_num = 3
cond.release()
while len(results2) < 5:
_wait()
self.assertEqual(results1, [1] * 3 + [2] * 2)
self.assertEqual(results2, [2] * 3 + [3] * 2)
b.wait_for_finished()
def test_notify(self):
cond = self.condtype()
self._check_notify(cond)
# A second time, to check internal state is still ok.
self._check_notify(cond)
def test_timeout(self):
cond = self.condtype()
results = []
N = 5
def f():
cond.acquire()
t1 = time.time()
cond.wait(0.2)
t2 = time.time()
cond.release()
results.append(t2 - t1)
Bunch(f, N).wait_for_finished()
self.assertEqual(len(results), 5)
for dt in results:
self.assertTrue(dt >= 0.2, dt)
class BaseSemaphoreTests(BaseTestCase):
"""
Common tests for {bounded, unbounded} semaphore objects.
"""
def test_constructor(self):
self.assertRaises(ValueError, self.semtype, value = -1)
self.assertRaises(ValueError, self.semtype, value = -sys.maxint)
def test_acquire(self):
sem = self.semtype(1)
sem.acquire()
sem.release()
sem = self.semtype(2)
sem.acquire()
sem.acquire()
sem.release()
sem.release()
def test_acquire_destroy(self):
sem = self.semtype()
sem.acquire()
del sem
def test_acquire_contended(self):
sem = self.semtype(7)
sem.acquire()
N = 10
results1 = []
results2 = []
phase_num = 0
def f():
sem.acquire()
results1.append(phase_num)
sem.acquire()
results2.append(phase_num)
b = Bunch(f, 10)
b.wait_for_started()
while len(results1) + len(results2) < 6:
_wait()
self.assertEqual(results1 + results2, [0] * 6)
phase_num = 1
for i in range(7):
sem.release()
while len(results1) + len(results2) < 13:
_wait()
self.assertEqual(sorted(results1 + results2), [0] * 6 + [1] * 7)
phase_num = 2
for i in range(6):
sem.release()
while len(results1) + len(results2) < 19:
_wait()
self.assertEqual(sorted(results1 + results2), [0] * 6 + [1] * 7 + [2] * 6)
# The semaphore is still locked
self.assertFalse(sem.acquire(False))
# Final release, to let the last thread finish
sem.release()
b.wait_for_finished()
def test_try_acquire(self):
sem = self.semtype(2)
self.assertTrue(sem.acquire(False))
self.assertTrue(sem.acquire(False))
self.assertFalse(sem.acquire(False))
sem.release()
self.assertTrue(sem.acquire(False))
def test_try_acquire_contended(self):
sem = self.semtype(4)
sem.acquire()
results = []
def f():
results.append(sem.acquire(False))
results.append(sem.acquire(False))
Bunch(f, 5).wait_for_finished()
# There can be a thread switch between acquiring the semaphore and
# appending the result, therefore results will not necessarily be
# ordered.
self.assertEqual(sorted(results), [False] * 7 + [True] * 3 )
def test_default_value(self):
# The default initial value is 1.
sem = self.semtype()
sem.acquire()
def f():
sem.acquire()
sem.release()
b = Bunch(f, 1)
b.wait_for_started()
_wait()
self.assertFalse(b.finished)
sem.release()
b.wait_for_finished()
def test_with(self):
sem = self.semtype(2)
def _with(err=None):
with sem:
self.assertTrue(sem.acquire(False))
sem.release()
with sem:
self.assertFalse(sem.acquire(False))
if err:
raise err
_with()
self.assertTrue(sem.acquire(False))
sem.release()
self.assertRaises(TypeError, _with, TypeError)
self.assertTrue(sem.acquire(False))
sem.release()
class SemaphoreTests(BaseSemaphoreTests):
"""
Tests for unbounded semaphores.
"""
def test_release_unacquired(self):
# Unbounded releases are allowed and increment the semaphore's value
sem = self.semtype(1)
sem.release()
sem.acquire()
sem.acquire()
sem.release()
class BoundedSemaphoreTests(BaseSemaphoreTests):
"""
Tests for bounded semaphores.
"""
def test_release_unacquired(self):
# Cannot go past the initial value
sem = self.semtype()
self.assertRaises(ValueError, sem.release)
sem.acquire()
sem.release()
self.assertRaises(ValueError, sem.release)

7
Lib/test/test_thread.py
View File

@ -5,6 +5,7 @@ from test import test_support
import thread
import time
from test import lock_tests
NUMTASKS = 10
NUMTRIPS = 3
@ -164,8 +165,12 @@ class BarrierTest(BasicThreadTest):
self.done_mutex.release()
class LockTests(lock_tests.LockTests):
locktype = thread.allocate_lock
def test_main():
test_support.run_unittest(ThreadRunningTests, BarrierTest)
test_support.run_unittest(ThreadRunningTests, BarrierTest, LockTests)
if __name__ == "__main__":
test_main()

52
Lib/test/test_threading.py
View File

@ -11,6 +11,8 @@ import time
import unittest
import weakref
from test import lock_tests
# A trivial mutable counter.
class Counter(object):
def __init__(self):
@ -132,11 +134,9 @@ class ThreadTests(unittest.TestCase):
def test_foreign_thread(self):
# Check that a "foreign" thread can use the threading module.
def f(mutex):
# Acquiring an RLock forces an entry for the foreign
# Calling current_thread() forces an entry for the foreign
# thread to get made in the threading._active map.
r = threading.RLock()
r.acquire()
r.release()
threading.current_thread()
mutex.release()
mutex = threading.Lock()
@ -453,22 +453,6 @@ class ThreadingExceptionTests(unittest.TestCase):
thread.start()
self.assertRaises(RuntimeError, thread.start)
def test_releasing_unacquired_rlock(self):
rlock = threading.RLock()
self.assertRaises(RuntimeError, rlock.release)
def test_waiting_on_unacquired_condition(self):
cond = threading.Condition()
self.assertRaises(RuntimeError, cond.wait)
def test_notify_on_unacquired_condition(self):
cond = threading.Condition()
self.assertRaises(RuntimeError, cond.notify)
def test_semaphore_with_negative_value(self):
self.assertRaises(ValueError, threading.Semaphore, value = -1)
self.assertRaises(ValueError, threading.Semaphore, value = -sys.maxint)
def test_joining_current_thread(self):
current_thread = threading.current_thread()
self.assertRaises(RuntimeError, current_thread.join);
@ -483,8 +467,34 @@ class ThreadingExceptionTests(unittest.TestCase):
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)
def test_main():
test.test_support.run_unittest(ThreadTests,
test.test_support.run_unittest(LockTests, RLockTests, EventTests,
ConditionAsRLockTests, ConditionTests,
SemaphoreTests, BoundedSemaphoreTests,
ThreadTests,
ThreadJoinOnShutdown,
ThreadingExceptionTests,
)

18
Lib/threading.py
View File

@ -106,14 +106,16 @@ class _RLock(_Verbose):
def __repr__(self):
owner = self.__owner
return "<%s(%s, %d)>" % (
self.__class__.__name__,
owner and owner.name,
self.__count)
try:
owner = _active[owner].name
except KeyError:
pass
return "<%s owner=%r count=%d>" % (
self.__class__.__name__, owner, self.__count)
def acquire(self, blocking=1):
me = current_thread()
if self.__owner is me:
me = _get_ident()
if self.__owner == me:
self.__count = self.__count + 1
if __debug__:
self._note("%s.acquire(%s): recursive success", self, blocking)
@ -132,7 +134,7 @@ class _RLock(_Verbose):
__enter__ = acquire
def release(self):
if self.__owner is not current_thread():
if self.__owner != _get_ident():
raise RuntimeError("cannot release un-acquired lock")
self.__count = count = self.__count - 1
if not count:
@ -168,7 +170,7 @@ class _RLock(_Verbose):
return (count, owner)
def _is_owned(self):
return self.__owner is current_thread()
return self.__owner == _get_ident()
def Condition(*args, **kwargs):

7
Misc/NEWS
View File

@ -24,6 +24,10 @@ Core and Builtins
Library
-------
- Issue #7282: Fix a memory leak when an RLock was used in a thread other
than those started through `threading.Thread` (for example, using
`thread.start_new_thread()`.
- Issue #7264: Fix a possible deadlock when deallocating thread-local objects
which are part of a reference cycle.
@ -71,6 +75,9 @@ Build
Tests
-----
- Issue #7270: Add some dedicated unit tests for multi-thread synchronization
primitives such as Lock, RLock, Condition, Event and Semaphore.
- Issue #7055: test___all__ now greedily detects all modules which have an
__all__ attribute, rather than using a hardcoded and incomplete list.