8

Mypy produce an error with this dataclass inheritance: 

import dataclasses
import datetime

import typing


@dataclasses.dataclass
class Crud:
    creation_datetime: typing.Optional[datetime.datetime] = dataclasses.field(init=False)

    def __post_init__(self) -> None:
        self.creation_datetime = getattr(self, "creation_datetime", datetime.datetime.utcnow())


@dataclasses.dataclass
class MyFoo(Crud):
    name: str

t.py:17: error: Attributes without a default cannot follow attributes with one

Does exist a way to supress this error or design the code differently to avoid mypy error ?

bux
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  • A technical explanation and a workaround are provided here: https://stackoverflow.com/questions/51575931/class-inheritance-in-python-3-7-dataclasses. It does not really answer to *why* though. – Joël Jan 26 '21 at 09:30

1 Answers1

-4

For information, this error can be avoided with # type: ignore

@dataclasses.dataclass
class MyFoo(Crud):
    name: str  # type: ignore
bux
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