[ty] Support dataclass_transform as a function call

[charliermarsh]

Summary

Instead of just as a decorator.

Closes astral-sh/ty#2319.

[astral-sh-bot]

Diagnostic diff on typing conformance tests

No changes detected when running ty on typing conformance tests ✅

[astral-sh-bot]

mypy_primer results

Changes were detected when running on open source projects

attrs (https://github.com/python-attrs/attrs)
- tests/test_annotations.py:644:13: error[invalid-assignment] Object of type `<decorator produced by dataclass-like function>` is not assignable to `<class 'C'>`
+ tests/test_annotations.py:644:13: error[invalid-assignment] Object of type `<class 'tests.test_annotations.TestAnnotations.<locals of function 'test_init_type_hints_fake_module'>.C @ tests/test_annotations.py:640'>` is not assignable to `<class 'tests.test_annotations.TestAnnotations.<locals of function 'test_init_type_hints_fake_module'>.C @ tests/test_annotations.py:640'>`
- tests/test_make.py:620:13: error[invalid-assignment] Object of type `<decorator produced by dataclass-like function>` is not assignable to `<class 'C'>`
+ tests/test_make.py:620:13: error[invalid-assignment] Object of type `<class 'tests.test_make.TestAttributes.<locals of function 'test_adds_all_by_default'>.C @ tests/test_make.py:615'>` is not assignable to `<class 'tests.test_make.TestAttributes.<locals of function 'test_adds_all_by_default'>.C @ tests/test_make.py:615'>`

pydantic (https://github.com/pydantic/pydantic)
- pydantic/fields.py:943:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, int | float | str | ... omitted 3 union elements] | ((dict[str, int | float | str | ... omitted 3 union elements], /) -> None) | None`
+ pydantic/fields.py:943:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, Divergent] | ((dict[str, Divergent], /) -> None) | None`
- pydantic/fields.py:983:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, int | float | str | ... omitted 3 union elements] | ((dict[str, int | float | str | ... omitted 3 union elements], /) -> None) | None`
+ pydantic/fields.py:983:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, Divergent] | ((dict[str, Divergent], /) -> None) | None`
- pydantic/fields.py:1026:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, int | float | str | ... omitted 3 union elements] | ((dict[str, int | float | str | ... omitted 3 union elements], /) -> None) | None`
+ pydantic/fields.py:1026:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, Divergent] | ((dict[str, Divergent], /) -> None) | None`
- pydantic/fields.py:1066:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, int | float | str | ... omitted 3 union elements] | ((dict[str, int | float | str | ... omitted 3 union elements], /) -> None) | None`
+ pydantic/fields.py:1066:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, Divergent] | ((dict[str, Divergent], /) -> None) | None`
- pydantic/fields.py:1109:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, int | float | str | ... omitted 3 union elements] | ((dict[str, int | float | str | ... omitted 3 union elements], /) -> None) | None`
+ pydantic/fields.py:1109:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, Divergent] | ((dict[str, Divergent], /) -> None) | None`
- pydantic/fields.py:1148:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, int | float | str | ... omitted 3 union elements] | ((dict[str, int | float | str | ... omitted 3 union elements], /) -> None) | None`
+ pydantic/fields.py:1148:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, Divergent] | ((dict[str, Divergent], /) -> None) | None`
- pydantic/fields.py:1188:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, int | float | str | ... omitted 3 union elements] | ((dict[str, int | float | str | ... omitted 3 union elements], /) -> None) | None`
+ pydantic/fields.py:1188:5: error[invalid-parameter-default] Default value of type `PydanticUndefinedType` is not assignable to annotated parameter type `dict[str, Divergent] | ((dict[str, Divergent], /) -> None) | None`
- pydantic/fields.py:1567:13: error[invalid-argument-type] Argument is incorrect: Expected `dict[str, int | float | str | ... omitted 3 union elements] | ((dict[str, int | float | str | ... omitted 3 union elements], /) -> None) | None`, found `Top[dict[Unknown, Unknown]] | (((dict[str, int | float | str | ... omitted 3 union elements], /) -> None) & ~Top[dict[Unknown, Unknown]]) | None`
+ pydantic/fields.py:1567:13: error[invalid-argument-type] Argument is incorrect: Expected `dict[str, Divergent] | ((dict[str, Divergent], /) -> None) | None`, found `Top[dict[Unknown, Unknown]] | (((dict[str, Divergent], /) -> None) & ~Top[dict[Unknown, Unknown]]) | None`

xarray (https://github.com/pydata/xarray)
- xarray/core/dataarray.py:5757:16: error[invalid-return-type] Return type does not match returned value: expected `T_Xarray@map_blocks`, found `DataArray | Dataset`
+ xarray/core/dataarray.py:5757:16: error[invalid-return-type] Return type does not match returned value: expected `T_Xarray@map_blocks`, found `T_Xarray@map_blocks | DataArray | Dataset`

prefect (https://github.com/PrefectHQ/prefect)
- src/prefect/deployments/runner.py:795:70: warning[possibly-missing-attribute] Attribute `__name__` may be missing on object of type `Unknown | (((...) -> Any) & ((*args: object, **kwargs: object) -> object))`
+ src/prefect/deployments/runner.py:795:70: warning[possibly-missing-attribute] Attribute `__name__` may be missing on object of type `Unknown | ((...) -> Any)`
+ src/prefect/flow_engine.py:812:32: error[invalid-await] `Unknown | R@FlowRunEngine | Coroutine[Any, Any, R@FlowRunEngine]` is not awaitable
+ src/prefect/flow_engine.py:1401:24: error[invalid-await] `Unknown | R@AsyncFlowRunEngine | Coroutine[Any, Any, R@AsyncFlowRunEngine]` is not awaitable
+ src/prefect/flow_engine.py:1482:43: error[invalid-argument-type] Argument to function `next` is incorrect: Expected `SupportsNext[Unknown]`, found `Unknown | R@run_generator_flow_sync`
+ src/prefect/flow_engine.py:1490:21: warning[possibly-missing-attribute] Attribute `throw` may be missing on object of type `Unknown | R@run_generator_flow_sync`
+ src/prefect/flow_engine.py:1524:44: warning[possibly-missing-attribute] Attribute `__anext__` may be missing on object of type `Unknown | R@run_generator_flow_async`
+ src/prefect/flow_engine.py:1531:25: warning[possibly-missing-attribute] Attribute `throw` may be missing on object of type `Unknown | R@run_generator_flow_async`
- src/prefect/flows.py:286:34: error[unresolved-attribute] Object of type `((**P@Flow) -> R@Flow) & ((*args: object, **kwargs: object) -> object)` has no attribute `__name__`
+ src/prefect/flows.py:286:34: error[unresolved-attribute] Object of type `(**P@Flow) -> R@Flow` has no attribute `__name__`
- src/prefect/flows.py:404:68: error[unresolved-attribute] Object of type `((**P@Flow) -> R@Flow) & ((*args: object, **kwargs: object) -> object)` has no attribute `__name__`
+ src/prefect/flows.py:404:68: error[unresolved-attribute] Object of type `(**P@Flow) -> R@Flow` has no attribute `__name__`
- src/prefect/flows.py:1750:53: warning[unused-ignore-comment] Unused blanket `type: ignore` directive
- Found 5526 diagnostics
+ Found 5531 diagnostics

scikit-build-core (https://github.com/scikit-build/scikit-build-core)
- src/scikit_build_core/build/wheel.py:98:20: error[no-matching-overload] No overload of bound method `__init__` matches arguments
- Found 48 diagnostics
+ Found 47 diagnostics

pandas-stubs (https://github.com/pandas-dev/pandas-stubs)
- pandas-stubs/_typing.pyi:1232:16: warning[unused-ignore-comment] Unused blanket `type: ignore` directive
- Found 5156 diagnostics
+ Found 5155 diagnostics

rotki (https://github.com/rotki/rotki)
- rotkehlchen/chain/decoding/tools.py:99:13: error[invalid-argument-type] Argument to function `decode_transfer_direction` is incorrect: Expected `Sequence[A@BaseDecoderTools]`, found `Unknown | tuple[BTCAddress, ...] | tuple[ChecksumAddress, ...] | tuple[SubstrateAddress, ...] | tuple[SolanaAddress, ...]`
+ rotkehlchen/chain/decoding/tools.py:97:13: error[invalid-argument-type] Argument to function `decode_transfer_direction` is incorrect: Expected `(A@BaseDecoderTools & BTCAddress) | (A@BaseDecoderTools & ChecksumAddress) | (A@BaseDecoderTools & SubstrateAddress) | (A@BaseDecoderTools & SolanaAddress)`, found `A@BaseDecoderTools`
+ rotkehlchen/chain/decoding/tools.py:98:13: error[invalid-argument-type] Argument to function `decode_transfer_direction` is incorrect: Expected `(A@BaseDecoderTools & BTCAddress) | (A@BaseDecoderTools & ChecksumAddress) | (A@BaseDecoderTools & SubstrateAddress) | (A@BaseDecoderTools & SolanaAddress) | None`, found `A@BaseDecoderTools | None`
+ rotkehlchen/chain/decoding/tools.py:99:13: error[invalid-argument-type] Argument to function `decode_transfer_direction` is incorrect: Expected `Sequence[(A@BaseDecoderTools & BTCAddress) | (A@BaseDecoderTools & ChecksumAddress) | (A@BaseDecoderTools & SubstrateAddress) | (A@BaseDecoderTools & SolanaAddress)]`, found `Unknown | tuple[BTCAddress, ...] | tuple[ChecksumAddress, ...] | tuple[SubstrateAddress, ...] | tuple[SolanaAddress, ...]`
- Found 2093 diagnostics
+ Found 2095 diagnostics

No memory usage changes detected ✅

[charliermarsh]

(The hydra-zen diagnostic needs work.)

[charliermarsh]

I think this is wrong. It's intended to address cases like:

@dataclass_transform()
def hydrated_dataclass(target: type, *, frozen: bool = False) -> Callable[[type[T]], type[T]]:
    def decorator(cls: type[T]) -> type[T]:
        return cls
    return decorator

@hydrated_dataclass(SomeConfig, frozen=True)
class MyConfig:
    pass

If we make this change without this declared return type handling, then hydrated_dataclass(SomeConfig, frozen=True) returns type[SomeConfig] with dataclass params, and we apply that as a decorator.