How to enforce stricter Any type checking in Pyright strict mode?

[rafrafek]

Hello,
I'm using Pyright in strict mode, and I need the Any type to be validated. I want the type checker to prevent me from using Any where a function specifically requires a string, but allow it for functions that can handle a parameter of any type. I'm not sure whether Any means "any type" or "ignore type" in Python. Should I continue using Any, or should I use a different type annotation, like object, to achieve that?

from typing import Any


def accept_any(foo: Any) -> None:
    print(type(foo))  # Should be OK, but it's not OK


def accept_str(bar: str) -> None:
    print(type(bar))


def call_the_functions_above(foo: Any) -> None:
    accept_any(foo)  # Should be OK, and it's OK

    accept_str(foo)  # Should not be OK, but it's OK

[erictraut]

Any has a very specific meaning in the Python typing spec, and pyright conforms to the spec. For more details, refer to this section of the spec.

If you want your code to be fully type checked, you should avoid using Any wherever possible. When you use Any, you're effectively telling the type checker "I don't know what type this is, so assume that it's any type that could possibly satisfy type checking constraints".

[rafrafek]

Thank you for the clarification! That makes sense. I'll use object instead of Any for stricter type validation.