Classes and instances produced by dataclasses.make_dataclass are not pickleable #102103
Description
Repro:
## Setup
>>> import pickle
>>> import dataclasses
>>> A = dataclasses.make_dataclass('A', [])
>>> @dataclasses.dataclass
... class B: pass
...
## Correct
>>> pickle.loads(pickle.dumps(B))
<class '__main__.B'>
>>> pickle.loads(pickle.dumps(B()))
B()
## Wrong
>>> pickle.load(pickle.dump(A))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
_pickle.PicklingError: Can't pickle <class 'types.A'>: attribute lookup A on types failed
>>> pickle.loads(pickle.dumps(A()))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
_pickle.PicklingError: Can't pickle <class 'types.A'>: attribute lookup A on types failedI think that this happens because of this:
>>> A.__module__
'types'
>>> B.__module__
'__main__'After a manual fix it works as it should:
>>> A.__module__ = '__main__'
>>> pickle.loads(pickle.dumps(A()))
A()So, I propose to do it for all dataclasses that we create in make_dataclass.
I have a simple PR ready, it is inspired by namedtuple's logic :)