Fix ListenerHandler race condition #1495
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mdickinson
commented
Sep 2, 2021
| @@ -1195,22 +1195,15 @@ def owner_deleted(self, ref): | |||
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| class ListenerHandler(object): | |||
| def __init__(self, handler): | |||
| if type(handler) is MethodType: | |||
| object = handler.__self__ | |||
| if object is not None: | |||
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In Python 3, there's no normal situation where handler can be an instance of MethodType and handler.__self__ can be None, so I've removed this branch. (This code is likely a leftover from Python 2, where this branch catches unbound methods.)
mdickinson
commented
Sep 2, 2021
| @@ -1195,22 +1195,15 @@ def owner_deleted(self, ref): | |||
|
|
|||
| class ListenerHandler(object): | |||
| def __init__(self, handler): | |||
| if type(handler) is MethodType: | |||
There was a problem hiding this comment.
I can't see a good reason to do an exact type check rather than the usual isinstance check here.
corranwebster
approved these changes
Sep 6, 2021
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Fixes #1494.
I've added a couple of unit tests for
ListenerHandler, testing the two main use-cases (methods and functions as handlers). I don't have a regression test for the race condition - the race condition exists, but is almost impossible to reproduce programmatically.