Metaclass `__call__` breaks annotation hover of `__init__` in class using the Metadata

[OlavMSG]

Summary

There is a difference in annotation hover and type hint display between ty and Pylance when defining a metaclass with __call__ and a class defining its own __init__ and using the metaclass.

Examlpe code:

from typing import Any, TypeVar, reveal_type

T = TypeVar("T")


class TestMeta(type):
    def __call__(cls: type[T], *args: Any, **kwargs: Any) -> T:  # noqa: ANN401
        # expected to have more logic here...
        return super().__call__(*args, **kwargs)  # ty:ignore[invalid-super-argument]


class TestWithMeta(metaclass=TestMeta):
    def __init__(self, val1: str, val2: int, val3: int | None = None) -> None: ...


class TestWithoutMeta:
    def __init__(self, val1: str, val2: int, val3: int | None = None) -> None: ...


value1 = "val1"
value2 = 2
val_test11 = TestWithMeta(value1, value2)
# Displays TestWithMeta(...) on hover in ty
# but class TestWithMeta(
#     val1: str,
#     val2: int,
#     val3: int | None = None
# ) in Pylance
val_test12 = TestWithoutMeta(value1, value2)
# Displays class TestWithoutMeta(
#     val1: str,
#     val2: int,
#     val3: int | None = None
# ) in ty and Pylance
reveal_type(val_test11)  # Runtime type is 'TestWithMeta'
reveal_type(val_test12)  # Runtime type is 'TestWithoutMeta'

Schreenshot ty:

Schreenshot Pylance:

This Pyright issue seams to be same or similar: microsoft/pyright#5488

I also assume it may be related to the resent changes because of: #2288

Version

ty 0.0.29

[sharkdp]

Thank you for reporting this.

@carljm From a brief look, it seems like we should probably take the signatures of all (up to three) constructors into account when displaying the signature in the LSP, similar to how type context from all constructors is taken into account. Of course, that still leaves the question which signature should be displayed, but it seems reasonable to take the one from the constructor that is called last (here: __init__), instead of the one that is being called first?

It feels like ideally, the signatures would be combined somehow (via an intersection), but that seems hard. And it does not seem like that would result in the best type for displaying in this particular example (as it would mix in Any).