I'm still trying to understand the behaviour that I'm seeing but I'm already pretty sure that it's either a bug, or something that would be considered a bug if it didn't perhaps avoid even worse behaviour.
Inside the join() method of threading.Thread objects, a Condition named self.__block is acquired, and then the wait logic is executed. After the wait() finishes, self.__block is released and the method returns.
If you hit Ctrl-C while the join's wait() is occurring, you'll raise a KeyboardInterrupt and bypass the release() call. (I'm observing this on Win XP with Python 2.4 but have no reason to think it wouldn't work the same on other platforms, given the docs on signals and such.) If you do this, the thread you were waiting for will never be able to complete its cleanup because __bootstrap() calls __stop() and that tries to acquire the same Condition object, which has never been released. (I suspect this will happen only if its the MainThread that is doing the join() call since KeyboardInterrupts only occur in the main thread.)
A simple try/finally in join() appears to solve the problem, but I'm unsure that this is a good idea, partly because I'm a little surprised nobody else has found this problem before and I lack confidence that I've really found a bug.
Anyone have thoughts on this? I'll file a bug report shortly unless someone can point out the error in my reasoning or a reason why this must be the way it is.
-Peter -- http://mail.python.org/mailman/listinfo/python-list