The subclass in Callable

[HouLingLXH]

EventTest is the subclass of EventBase, how to fixed it?

[carljm]

You asked for a callable that can take any EventBase as an argument, you provided one that only accepts an EventTest. This is a type error because the thing you provided is "less capable" than the expected type. In type system terms, a callable type is "contravariant" in its accepted arguments: if you accept only a subtype of the arguments of another callable type, that makes you a supertype of it -- the relationship is reversed.

In this case, you either need to provide a callback that can accept any EventBase, or you might want to use a typevar (eg EventBaseT = TypeVar("EventBaseT", bound=EventBase) to replace EventBase in the type annotations.

[TeamSpen210]

You want event_class: type[TEventBase] to indicate it requires the type itself not a subclass.

[HouLingLXH]

I want to rule the type of param in Callable by the type of event_class , rather than only is the subclass of EventBase.
add_listener(AEvent,call_testA) √
add_listener(BEvent,call_back) √
add_listener(BEvent,call_testA) ×

[Akuli]

As the answer says, you can use a TypeVar:

from typing import TypeVar, Callable

class EventBase:
    pass

class EventA(EventBase):
    pass

class EventB(EventBase):
    pass

T = TypeVar("T", bound=EventBase)

def add_listener(event_class: type[T], want_do: Callable[[T], None]) -> None:
    pass

def foo(data: EventA) -> None:
    pass

add_listener(EventA, foo)  # ok
add_listener(EventB, foo)  # error: Argument 2 to "add_listener" has incompatible type "Callable[[EventA], None]"; expected "Callable[[EventB], None]"

[HouLingLXH]

Why not error in my pycharm?

[carljm]

I don't use Pycharm so not sure. It's possible that pycharm is focused more on autocomplete etc and not so much on type errors and is more permissive than dedicated type checkers like mypy or pyre or pyright.