http://hg.python.org/cpython/rev/8c15e57830dd changeset: 83030:8c15e57830dd parent: 83026:411e5726f84d parent: 83029:2698920eadcd user: R David Murray <rdmurray@bitdance.com> date: Sat Mar 30 17:22:30 2013 -0400 summary: Merge #17435: Don't use mutable default values in Timer. Patch by Denver Coneybeare with some test modifications by me. files: Doc/library/threading.rst | 4 ++- Lib/test/test_threading.py | 39 ++++++++++++++++++-------- Lib/threading.py | 8 ++-- Misc/NEWS | 3 ++ 4 files changed, 37 insertions(+), 17 deletions(-) diff --git a/Doc/library/threading.rst b/Doc/library/threading.rst --- a/Doc/library/threading.rst +++ b/Doc/library/threading.rst @@ -839,10 +839,12 @@ t.start() # after 30 seconds, "hello, world" will be printed -.. class:: Timer(interval, function, args=[], kwargs={}) +.. class:: Timer(interval, function, args=None, kwargs=None) Create a timer that will run *function* with arguments *args* and keyword arguments *kwargs*, after *interval* seconds have passed. + If *args* is None (the default) then an empty list will be used. + If *kwargs* is None (the default) then an empty dict will be used. .. versionchanged:: 3.3 changed from a factory function to a class. diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py --- a/Lib/test/test_threading.py +++ b/Lib/test/test_threading.py @@ -787,6 +787,32 @@ self.assertEqual(p.returncode, 0, "Unexpected error: " + stderr.decode()) self.assertEqual(data, expected_output) +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, [((), {}), ((), {})]) + + 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) @@ -816,16 +842,5 @@ class BarrierTests(lock_tests.BarrierTests): barriertype = staticmethod(threading.Barrier) - -def test_main(): - test.support.run_unittest(LockTests, PyRLockTests, CRLockTests, EventTests, - ConditionAsRLockTests, ConditionTests, - SemaphoreTests, BoundedSemaphoreTests, - ThreadTests, - ThreadJoinOnShutdown, - ThreadingExceptionTests, - BarrierTests, - ) - if __name__ == "__main__": - test_main() + unittest.main() diff --git a/Lib/threading.py b/Lib/threading.py --- a/Lib/threading.py +++ b/Lib/threading.py @@ -807,17 +807,17 @@ class Timer(Thread): """Call a function after a specified number of seconds: - t = Timer(30.0, f, args=[], kwargs={}) + t = Timer(30.0, f, args=None, kwargs=None) t.start() t.cancel() # stop the timer's action if it's still waiting """ - def __init__(self, interval, function, args=[], kwargs={}): + def __init__(self, interval, function, args=None, kwargs=None): Thread.__init__(self) self.interval = interval self.function = function - self.args = args - self.kwargs = kwargs + self.args = args if args is not None else [] + self.kwargs = kwargs if kwargs is not None else {} self.finished = Event() def cancel(self): diff --git a/Misc/NEWS b/Misc/NEWS --- a/Misc/NEWS +++ b/Misc/NEWS @@ -297,6 +297,9 @@ Library ------- +- Issue #17435: threading.Timer's __init__ method no longer uses mutable + default values for the args and kwargs parameters. + - Issue #17526: fix an IndexError raised while passing code without filename to inspect.findsource(). Initial patch by Tyler Doyle. -- Repository URL: http://hg.python.org/cpython