test-data/unit/plugins/add_overloaded_method.py

from __future__ import annotations

from typing import Callable

from mypy.nodes import ARG_POS, Argument, Var
from mypy.plugin import ClassDefContext, Plugin
from mypy.plugins.common import MethodSpec, add_overloaded_method_to_class


class OverloadedMethodPlugin(Plugin):
    def get_base_class_hook(self, fullname: str) -> Callable[[ClassDefContext], None] | None:
        if "AddOverloadedMethod" in fullname:
            return add_overloaded_method_hook
        return None


def add_overloaded_method_hook(ctx: ClassDefContext) -> None:
    add_overloaded_method_to_class(ctx.api, ctx.cls, "method", _generate_method_specs(ctx))
    add_overloaded_method_to_class(
        ctx.api, ctx.cls, "clsmethod", _generate_method_specs(ctx), is_classmethod=True
    )
    add_overloaded_method_to_class(
        ctx.api, ctx.cls, "stmethod", _generate_method_specs(ctx), is_staticmethod=True
    )


def _generate_method_specs(ctx: ClassDefContext) -> list[MethodSpec]:
    return [
        MethodSpec(
            args=[Argument(Var("arg"), ctx.api.named_type("builtins.int"), None, ARG_POS)],
            return_type=ctx.api.named_type("builtins.str"),
        ),
        MethodSpec(
            args=[Argument(Var("arg"), ctx.api.named_type("builtins.str"), None, ARG_POS)],
            return_type=ctx.api.named_type("builtins.int"),
        ),
    ]


def plugin(version: str) -> type[OverloadedMethodPlugin]:
    return OverloadedMethodPlugin