| from __future__ import annotations |
| |
| from typing import Callable |
| |
| from mypy.plugin import AttributeContext, Plugin |
| from mypy.types import AnyType, Type, TypeOfAny |
| |
| |
| class AttrPlugin(Plugin): |
| def get_attribute_hook(self, fullname: str) -> Callable[[AttributeContext], Type] | None: |
| if fullname == "m.Magic.magic_field": |
| return magic_field_callback |
| if fullname == "m.Magic.nonexistent_field": |
| return nonexistent_field_callback |
| if fullname == "m.Magic.no_assignment_field": |
| return no_assignment_field_callback |
| return None |
| |
| |
| def magic_field_callback(ctx: AttributeContext) -> Type: |
| return ctx.api.named_generic_type("builtins.str", []) |
| |
| |
| def nonexistent_field_callback(ctx: AttributeContext) -> Type: |
| ctx.api.fail("Field does not exist", ctx.context) |
| return AnyType(TypeOfAny.from_error) |
| |
| |
| def no_assignment_field_callback(ctx: AttributeContext) -> Type: |
| if ctx.is_lvalue: |
| ctx.api.fail(f"Cannot assign to field", ctx.context) |
| return AnyType(TypeOfAny.from_error) |
| return ctx.default_attr_type |
| |
| |
| def plugin(version: str) -> type[AttrPlugin]: |
| return AttrPlugin |
