diff options
| -rw-r--r-- | Lib/test/test_threading.py | 20 | ||||
| -rw-r--r-- | Lib/threading.py | 2 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2020-06-28-16-13-02.bpo-41149.jiZWtJ.rst | 1 |
3 files changed, 22 insertions, 1 deletions
diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py index 0a4372ec2df..a7a716ed59f 100644 --- a/Lib/test/test_threading.py +++ b/Lib/test/test_threading.py @@ -855,6 +855,26 @@ class ThreadTests(BaseTestCase): """) self.assertEqual(out.rstrip(), b"thread_dict.atexit = 'value'") + def test_boolean_target(self): + # bpo-41149: A thread that had a boolean value of False would not + # run, regardless of whether it was callable. The correct behaviour + # is for a thread to do nothing if its target is None, and to call + # the target otherwise. + class BooleanTarget(object): + def __init__(self): + self.ran = False + def __bool__(self): + return False + def __call__(self): + self.ran = True + + target = BooleanTarget() + thread = threading.Thread(target=target) + thread.start() + thread.join() + self.assertTrue(target.ran) + + class ThreadJoinOnShutdown(BaseTestCase): diff --git a/Lib/threading.py b/Lib/threading.py index 7b3d63dd211..ff2624a3e1e 100644 --- a/Lib/threading.py +++ b/Lib/threading.py @@ -906,7 +906,7 @@ class Thread: """ try: - if self._target: + if self._target is not None: self._target(*self._args, **self._kwargs) finally: # Avoid a refcycle if the thread is running a function with diff --git a/Misc/NEWS.d/next/Library/2020-06-28-16-13-02.bpo-41149.jiZWtJ.rst b/Misc/NEWS.d/next/Library/2020-06-28-16-13-02.bpo-41149.jiZWtJ.rst new file mode 100644 index 00000000000..abe09016a65 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2020-06-28-16-13-02.bpo-41149.jiZWtJ.rst @@ -0,0 +1 @@ +Allow executing callables that have a boolean value of ``False`` when passed to :class:`Threading.thread` as the target. Patch contributed by Barney Stratford. |