typing_extensions.Annotated not supported

[hodgespodge]

Howdy,

For the time being, I'm unfortunately stuck targeting python 3.8. As such, I am using the typing_extensions package to get Annotated.
My goal is to create a custom type checker using beartype.vale.Is. The code is confirmed to work with the new python typing, but fails for typing_extensions. I think it would be great to support typing_extensions.Annotated since beartype.beartype recommends using typing_extensions for python < 3.9 in its documentation.

import sys
from beartype.vale import Is
from plum import dispatch

if sys.version_info < (3, 9):
    from typing_extensions import Annotated
else:
    from typing import Annotated


class MyClass():
    def __init__(self) -> None:
        self.special_attr = 'special_value'

class ClassWithAnnotatedTypeChecker():

    my_type_check = Annotated[object, Is[lambda value: hasattr(value,'special_attr')]]

    @dispatch
    def myFunction(self, value: my_type_check):
        print(f'Value has special_attr={value.special_attr}')

    @dispatch
    def myFunction(self, value: str):
        print(f'Value is a string={value}')

    @dispatch
    def myFunction(self, value: int):
        print(f'Value is an int={value}')


my_class = MyClass()
my_class_with_annotated_type_checker = ClassWithAnnotatedTypeChecker()

# This all works for python >= 3.9
# Else: plum.resolver.ambiguousLookupError
my_class_with_annotated_type_checker.myFunction(my_class)
my_class_with_annotated_type_checker.myFunction('Hello')
my_class_with_annotated_type_checker.myFunction(1)

Thanks!

[wesselb]

Hey @hodgespodge! :)

I think the problem is as follows:

>>> from typing_extensions import Annotated

>>> from beartype.vale import Is

>>> from beartype.door import TypeHint, is_bearable

>>> is_bearable("hello", Annotated[object, Is[lambda value: hasattr(value, 'special_attr')]])
True

I've opened an issue at @beartype to get the bear master's (@leycec's) thoughts.

[leycec]

Resolved by beartype/beartype@76e609dd484339ae. I'm willing to pretend this didn't happen if everyone else is. 🥲

[wesselb]

@hodgespodge if this isn’t top-notch super quick bug solving, then I don’t know what is. Hats off to @leycec!

[hodgespodge]

Thanks a ton both of y'all!