New submission from John Didion <[email protected]>:
> @dataclass
> class Foo:
> x: dict = field(default_factory=dict)
> @dataclass
> class Bar(Foo):
> y: int = 1
> @dataclass
> class Baz(Foo):
> def blorf(self):
> print('hello')
> Foo().x
{}
> Bar().x
{}
> Baz().x
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: __init__() missing 1 required positional argument: 'x'
---
I understand that this is desired behavior when the subclass contains
non-default attributes. But subclasses that define no additional attributes
should work just the same as those that define only additional default
attributes.
A similar issue was raised and dismissed when dataclasses was in development on
GitHub: https://github.com/ericvsmith/dataclasses/issues/112, but that only
concerned the case of subclasses defining non-default attributes.
----------
messages: 312496
nosy: John Didion
priority: normal
severity: normal
status: open
title: Error when subclassing a dataclass with a field that uses a
defaultfactory
type: crash
versions: Python 3.7
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Python tracker <[email protected]>
<https://bugs.python.org/issue32896>
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