Sqlalchemy kartiertes Feld nicht richtig überprüft ⇐ Python

[Anonymous]

mit diesem Code: < /p>

Code: Select all

from typing import Protocol
from sqlalchemy import Integer
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column

class SpamProt(Protocol):
id: int

class Base(DeclarativeBase):
pass

class SpamModel(Base):
id: Mapped[int] = mapped_column(Integer())

def do_with_spam(d: SpamProt) -> None:
raise NotImplementedError()

if __name__ == "__main__":
spam = SpamModel(id=10)
do_with_spam(spam)
< /code>
mypy

gibt einen Fehler zurück:

Code: Select all

spam.py:24: error: Argument 1 to "do_with_spam" has incompatible type "SpamModel"; expected "SpamProt"  [arg-type]
spam.py:24: note: Following member(s) of "SpamModel" have conflicts:
spam.py:24: note:     id: expected "int", got "Mapped[int]"
Found 1 error in 1 file (checked 1 source file)
< /code>
As SQLAlchemy claims to have no fully compatible typing without any plugins, I don't understand why this simplest example doesn't work. It is not a result of invariance. It is not an effect of interference from old plugin (here's the whole environment):
╭───────────────────┬─────────┬──────────╮
│ name              │ version │ location │
├───────────────────┼─────────┼──────────┤
│ greenlet          │ 3.1.1   │          │
│ mypy              │ 1.15.0  │          │
│ mypy-extensions   │ 1.0.0   │          │
│ SQLAlchemy        │ 2.0.39  │          │
│ typing_extensions │ 4.12.2  │          │
╰───────────────────┴─────────┴──────────╯
< /code>
do I fundamentally misunderstand how the Mapped

Argumente sollten funktionieren?