Subclassed generic (Async)Resource fails py3.8.9

[EdwardBlair]

Given python-dependency-injector@4.35.2

# my_module.py
from typing import Any
from dependency_injector import resources

class MyDep:
    ...

class MyDepAsyncResource(resources.AsyncResource[MyDep]):
    async def init(self, *args: Any, **kwargs: Any) -> MyDep:
        return MyDep()

    async def shutdown(self, resource: MyDep) -> None:
        ...

# oh_no.py
from my_module import MyDepAsyncResource

Fails to run on python 3.8.9 with

$python oh_no.py
oh_no.py:1: in <module>
    from my_module import MyDepAsyncResource
my_module.py:7: in <module>
    class MyDepAsyncResource(resources.AsyncResource[MyDep]):
../../../Library/Caches/pypoetry/virtualenvs/xxxxxxx-py3.8/lib/python3.8/site-packages/dependency_injector/resources.py:20: in __getitem__
    return cls(item)
../../../.pyenv/versions/3.8.9/lib/python3.8/typing.py:875: in __new__
    obj = super().__new__(cls, *args, **kwds)
E   TypeError: object.__new__() takes exactly one argument (the type to instantiate)

Removing this seems to fix it

python-dependency-injector/src/dependency_injector/resources.py

Lines 18 to 20 in 155f598

	def __getitem__(cls, item):
	# Spike for Python 3.6
	return cls(item)

What's that for?

[rmk135]

Hey @EdwardBlair. I did have mypy tests for generic typing of these classes, but didn't have runtime testing when generic typing is used. It has been broken for a while. Thanks for reporting the issue.

I fixed it. PR #490 . The fix is in the develop branch. I can not publish it on PyPI right now because project has reached PyPI size limit. I'll go ahead with publishing right after size issue is addressed.

[rmk135]

PR #490 is published in 4.36.0.