🔒 Small mypy issue

[knotty herald]

I have the following method:

async def get_by_email(self, email: str) -> User | None:
    """Get a user by email."""
    return await self.session.scalar(select(User).where(User.email == email))

And mypy gives the following error:

error: Returning Any from function declared to return "User | None" [no-any-return]

If i change it to this though:

async def get_by_email(self, email: str) -> User | None:
      """Get a user by email."""
    result = await self.session.scalar(select(User).where(User.email == email))
    return result

The error disappears. I cant seem to find any information about why this happens. Any help would be appreciated

[wispy dome]

@knotty herald

Python help channel opened

Remember to:

• Ask your Python question, not if you can ask or if there's an expert who can help.
• Show a code sample as text (rather than a screenshot) and the error message, if you've got one.
• Explain what you expect to happen and what actually happens.

:warning: Do not pip install anything that isn't related to your question, especially if asked to over DMs.

Closes after a period of inactivity, or when you send !close.

[fluid citrus]

Sounds like a mypy bug, do you have an MRE? What does reveal_type say about various things in the expression

[knotty herald]

For an MRE

This shows the error

from __future__ import annotations

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column


class Base(DeclarativeBase):
    pass


class Model(Base):
    __tablename__ = "model"

    id: Mapped[int] = mapped_column(autoincrement=True, primary_key=True)


engine = create_async_engine("sqlite+aiosqlite:///:memory:")
session = AsyncSession(engine)


async def get_by_id(id: int) -> Model | None:
    return await session.scalar(select(Model).where(Model.id == id))

error: Returning Any from function declared to return "Model | None" [no-any-return]

And same thing, if i assign the result to a variable and return it

It dissapears

What exactly should i check with reveal_type?

[half shuttle]

There're similar issues with return await on mypy's bug tracker.
mypy hangs when checking this for me, do you have an example without sqlalchemy?

[knotty herald]

Ill see if i can make one

[wispy dome]

Python help channel closed for inactivity

This help channel has been closed. Feel free to create a new post in #1035199133436354600. To maximize your chances of getting a response, check out this guide on asking good questions.