fix: Allow inheriting dataclasses with defaults #7184
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please review |
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Looks like #7193 addressed the immediate issue. I am however keen on letting the test and extra logic be reviewed and if ok to merge to avoid the warning and ensure compat. |
| def test_can_inherit_stdlib_dataclasses_with_dataclass_fields(): | ||
| @dataclasses.dataclass | ||
| class Base: | ||
| a: int = dataclasses.field(default=5) | ||
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| class Model(BaseModel, Base): | ||
| pass | ||
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| assert Model().a == 5 |
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Can we also add a test for default_factory? I'm assuming it doesn't work?
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@adriangb I added a test that xfails. The internals of stdlib dataclasses does not assign default factory attributes to the class instance (meaning the warning isnt triggered in this case). It also means that you are right, the default factory is not propagated to the resulting FieldInfo instance (because the dataclass.Field isnt assigned to Base but rather Base.__dataclass_fields__.
@dataclasses.dataclass
class Base:
a: int = dataclasses.field(default_factory=lambda: 5)
assert hasattr(Base, 'a') # this failsThere was a problem hiding this comment.
The inheritance works fine if you provide a value, so for my usecase this isn't an important feature to support. I added a test for what we need to work, though.
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tests/test_dataclasses.py
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| @pytest.mark.xfail(raises=ValidationError, require=True) | ||
| def test_can_inherit_stdlib_dataclasses_default_factories_and_use_them(): | ||
| """This test documents that default factories are not supported""" | ||
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| @dataclasses.dataclass | ||
| class Base: | ||
| a: str = dataclasses.field(default_factory=lambda: 'TEST') | ||
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| class Model(BaseModel, Base): | ||
| pass | ||
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| assert Model().a == 'TEST' |
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I'd rather see with pytest.raises(...) since that's what we use elsewhere
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@adriangb Done! |
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please review |
Change Summary
This patch allows for a
pydantic.Basemodelclass to inherit a "pure" stdlib dataclass, even when the attribute name is set on the class instance, as is the case withdataclasses.fieldand default assignments.Related issue number
fix #6984
Checklist
Selected Reviewer: @hramezani