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dataclasses that inherit from Protocol subclasses have wrong __init__ #883
Description
I believe bpo-44806: Fix __init__ in subclasses of protocols has caused a regression when using a Dataclass.
In Python 3.9.7, a dataclass that inherits from a subclass of typing.Protocol (i.e., a user-defined protocol), does not have the correct __init__.
Demonstration
from dataclasses import dataclass
from typing import Protocol
class P(Protocol):
pass
@dataclass
class B(P):
value: str
print(B("test"))In 3.9.7:
Traceback (most recent call last):
File "test.py", line 11, in <module>
print(B("test"))
TypeError: B() takes no argumentsIn 3.9.6:
B(value='test')
Activity
srittau commentedon Sep 1, 2021
Please report this at bugs.python.org.
julianfortune commentedon Sep 1, 2021
Thanks for the fast response.
Python Issue
AthenaCaesura commentedon Feb 17, 2022
This bug was solved in python 3.10, however the issue still remains for 3.9.7.
Is there any workaround that one could use instead of upgrading? Since 3.9.7 is the last version of 3.9 saying we don't support 3.9.7 is more or less the same as saying we don't support 3.9.
I would like to keep the frozen option if at all possible.
hauntsaninja commentedon Feb 17, 2022
Python 3.9.10 is the latest release of 3.9 and presumably contains python/cpython#28132
(this also isn't the right issue tracker for further discussion of this, please redirect to bugs.python.org)