Wrong dataclass_transform parameter name used for DCTransformDeclarative

[ImogenBits]

Describe the bug

This is basically the same issue that happened to pydantic here. Previous versions of PEP 681 had dataclass_transform take a parameter called field_descriptors but this name was changed to field_specifiers. SQLAlchemy still uses the old name for MappedAsDataclass, here.

To Reproduce

from typing import reveal_type
from sqlalchemy.orm import DeclarativeBase, mapped_column, Mapped, MappedAsDataclass

class Model(MappedAsDataclass, DeclarativeBase):
    a: Mapped[int] = mapped_column(default=1)

reveal_type(Model.__init__)

Error

Type of "Model.__init__" is "(self: Model, a: SQLCoreOperations[int] | int = mapped_column(default=1)) -> None"

Versions

• Python: 3.11
• SQLAlchemy: 2.0.0rc1

Additional context

The type of the init method should be (self: Model, a: SQLCoreOperations[int] | int = 1) -> None, which it is if the dataclass_transform call on DCTransformDeclarative uses the correct parameter name.

[CaselIT]

Hi,

Thanks for reporting. Since mypy doesn't support this I guess it was not detected, since we are not currently running pyright on the code

@zzzeek maybe it would be good to try have also pyright run on the code (assuming it would detect this error)?

[CaselIT]

Hi,

Thanks for reporting. Since mypy doesn't support this I guess it was not detected, since we are not currently running pyright on the code

@zzzeek maybe it would be good to try have also pyright run on the code (assuming it would detect this error)?

It seems pyright still accepts both, so it would not have helped in any case:
https://github.com/microsoft/pyright/blob/ddc6932b9c53b09b9b32926addbcefcab37b9b2a/packages/pyright-internal/src/analyzer/dataClasses.ts#L802-L807

[sqla-tester]

Federico Caselli has proposed a fix for this issue in the main branch:

Use field_specifiers instead of deprecated field_descriptors https://gerrit.sqlalchemy.org/c/sqlalchemy/sqlalchemy/+/4346