Error with @inject typing and mypy

[zulrang]

This code works with mypy:

class MyClass:
    pass


di[MyClass] = MyClass()


async def my_async_func(my_class: MyClass) -> str:
    return MyClass.__class__.__name__


async def calling_func() -> str:
    return await my_async_func(di[MyClass])

While this code results in an error:

class MyClass:
    pass


di[MyClass] = MyClass()


@inject
async def my_async_func(my_class: MyClass) -> str:
    return MyClass.__class__.__name__


async def calling_func() -> str:
    return await my_async_func()

mypy error: error: Incompatible types in "await" (actual type "Union[Any, Callable[..., Any]]", expected type "Awaitable[Any]")

Aside from ignoring the calling line, is there any way to make mypy happy with the type returned from the @Inject decorator?

[dkraczkowski]

@zulrang Thanks for raising this issue, I think @Inject decorator return types might need a fix. Will update you later on today on this.

[seanlossef-kce]

Any update on this?

[andrewbutlerboudakiankce]

Any update on this?

[zulrang]

I think this will be necessary: https://peps.python.org/pep-0612/

[skewty]

This is also problematic in PyCharm 2023.,2.

@zulrang were you able to figure out typing using PEP612 that seems to work in PyCharm / VSCode?

Perhaps something more simple (and backwards compatible) is possible using typing.overload?

[andrewbutlerboudakiankce]

@overload
def inject(
        _service: None = None,
        alias: Any | None = None,
        bind: Dict[str, Any] | None = None,
        container: Container = di,
        use_factory: bool = False) -> Callable[[ServiceDefinition], ServiceResult]: ...


@overload
def inject(
        _service: ServiceDefinition,
        alias: Any | None = None,
        bind: Dict[str, Any] | None = None,
        container: Container = di,
        use_factory: bool = False) -> ServiceResult: ...

^Try this

[skewty]

Those overloads are not working for me in PyCharm.. Are they working for you in VSCode?

# Python version 3.11.4
from typing import Any, Callable, Type, TypeVar, cast, overload

from kink import Container as KinkContainer, di as kink_di, inject as kink_inject
from kink.inject import ServiceDefinition, ServiceResult

T = TypeVar("T")


class Container(KinkContainer):
    @overload
    def __getitem__(self, key: str) -> Any:
        ...

    @overload
    def __getitem__(self, key: Type[T]) -> T:
        ...

    def __getitem__(self, key):
        return super().__getitem__(key)


di = cast(Container, kink_di)


@overload
def inject(
    _service: None = None,
    alias: Any | None = None,
    bind: dict[str, Any] | None = None,
    container: Container = di,
    use_factory: bool = False,
) -> Callable[[ServiceDefinition], ServiceResult]:
    ...


@overload
def inject(
    _service: ServiceDefinition,
    alias: Any | None = None,
    bind: dict[str, Any] | None = None,
    container: Container = di,
    use_factory: bool = False,
) -> ServiceResult:
    ...


def inject(
    _service: ServiceDefinition = None,
    alias: Any = None,
    bind: dict[str, Any] = None,
    container: Container = di,
    use_factory: bool = False,
):
    return kink_inject(_service, alias, bind, container, use_factory)


@inject
class TestA:
    def as_dict(self) -> dict:
        return self.__dict__


@inject()
class TestB:
    def as_dict(self) -> dict:
        return self.__dict__


di[bytes].|    # auto-complete  -- but inject decorator not used
di[TestA].|    # no auto-complete
di[TestB].|    # no auto-complete

[seanlossef-kce]

Those overloads are working for me in vscode

[seanlossef-kce]

To clarify, those overloads fix the issue where mypy cannot resolve the return type of an injected function because the injected parameters are not being explicitly passed in.

It seems like the issue you're talking about might be different. I also do not get intellisense on the di container itself when doing di[TestA].

[andrewbutlerboudakiankce]

Adding inject overloads as well as overloads in your snippet to __getitem__, as well as an additional overload to __setitem__ as follows appears to work in VS Code for autocomplete:

    @overload
    def __setitem__(self, key: Type[T], value: T) -> None:
        ...

    @overload
    def __setitem__(self, key: str, value: Any) -> None:
        ...