[WIP/RFC] multiprocessing: proxy: keep _manager after forking #17333
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Fixes iterating over dicts:
import multiprocessing as mp
def run(d):
for k in d:
print(k)
manager = mp.Manager()
d = manager.dict({1: 2, 3: 4})
process = mp.Process(target=run, args=(d,))
process.start()
process.join()
With this fix:
_callmethod __iter__ #PROXY (('__next__', 'send', 'throw', 'close'), Token(typeid='Iterator', address='/tmp/pymp-wfn3r3nd/listener-ze4ow_dl', id='7f12414ca130'))
_callmethod __next__ #RETURN 1
1
_callmethod __next__ #RETURN 3
3
_callmethod __next__ #ERROR
Without:
_callmethod __iter__ #PROXY (('__next__', 'send', 'throw', 'close'), Token(typeid='Iterator', address='/tmp/pymp-uppzhf9p/listener-mvmwwxma', id='7f5b7b42da90'))
Process Process-2:
Traceback (most recent call last):
File "…/pyenv/3.8.0/lib/python3.8/multiprocessing/process.py", line 313, in _bootstrap
self.run()
File "…/pyenv/3.8.0/lib/python3.8/multiprocessing/process.py", line 108, in run
self._target(*self._args, **self._kwargs)
File "t-mp.py", line 5, in run
for k in d:
File "<string>", line 2, in __iter__
File "…/pyenv/3.8.0/lib/python3.8/multiprocessing/managers.py", line 842, in _callmethod
proxytype = self._manager._registry[token.typeid][-1]
AttributeError: 'NoneType' object has no attribute '_registry'
The line is from when multiprocessing was added in e711caf, so I am
probably missing something here? This PR is meant to get tests run with
it, and of course for any feedback already.
blueyed
added a commit
to blueyed/pytest
that referenced
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Nov 22, 2019
Use `dict.keys()` to work around `__iter__` not working with a multiprocessing DictProxy. Ref: python/cpython#17333 Fixes pytest-dev#6254. Ref: kevlened/pytest-parallel#36
blueyed
added a commit
to blueyed/pytest
that referenced
this pull request
Nov 22, 2019
Use `dict.keys()` to work around `__iter__` not working with a multiprocessing DictProxy. Ref: python/cpython#17333 Fixes pytest-dev#6254. Ref: kevlened/pytest-parallel#36 (cherry picked from commit 1f736a6)
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/cc @benjaminp |
vinaycalastry
pushed a commit
to vinaycalastry/pytest
that referenced
this pull request
Dec 11, 2019
Use `dict.keys()` to work around `__iter__` not working with a multiprocessing DictProxy. Ref: python/cpython#17333 Fixes pytest-dev#6254. Ref: kevlened/pytest-parallel#36
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@benjaminp Do you know why The above-referenced issue prevents dictionary syntax like However, |
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Fixes iterating over dicts:
With this fix:
Without:
The line is from when multiprocessing was added in e711caf, so I am
probably missing something here? This PR is meant to get tests run with
it, and of course for any feedback already.