I originally posted this as a question on StackOverflow thinking I was doing something wrong:

http://stackoverflow.com/questions/43834494/python-3-6-attributeerror-simplequeue-object-has-no-attribute-poll/43835368#43835368

But I think I found the solution and answered my own question. I'm pretty sure you need to set:

self._poll = self._reader.poll

in the __setstate__ method in the SimpleQueue class of queues.py from the multiprocessing library. Otherwise, I'd love to know an alternative solution.

Thanks!

Related commit is bdb1cf1ca56db25b33fb15dd91eef2cc32cd8973. A simple reproduce snippet:

import multiprocessing as mp

def foo(q):
    q.put('hello')
    assert not q.empty()

if __name__ == '__main__':
    mp.set_start_method('spawn')
    q = mp.SimpleQueue()
    p = mp.Process(target=foo, args=(q,))
    p.start()
    print(q.get())
    p.join()

LGTM. But can you convert the reproducer to a test?

Thanks for your reply Serhiy. Test added. :-)

New changeset 6f75bc003ab4d5294b0291289ae03f7a8d305f46 by Xiang Zhang in branch 'master':
bpo-30301: Fix AttributeError when using SimpleQueue.empty() (#1601)
https://github.com/python/cpython/commit/6f75bc003ab4d5294b0291289ae03f7a8d305f46

New changeset 9081b36f330964faa4dee3af03228d2ca7c71835 by Xiang Zhang in branch '3.5':
bpo-30301: Fix AttributeError when using SimpleQueue.empty() (#1601) (#1627)
https://github.com/python/cpython/commit/9081b36f330964faa4dee3af03228d2ca7c71835

New changeset 43d4c0329e2348540a3a16ac61b3032f04eefd34 by Xiang Zhang in branch '3.6':
bpo-30301: Fix AttributeError when using SimpleQueue.empty() (#1601) (#1628)
https://github.com/python/cpython/commit/43d4c0329e2348540a3a16ac61b3032f04eefd34