Hey Adam,
I'd spotted this a while back too, but I didn't know enough about how the machinery of async and ASGI works to say for certain that the wrapping up of callables into a get_response would always be static after init. So I'm glad you're pushing it, where I was too uncertain :)

When I was looking at it, I was thinking about re-using the _is_coroutine attribute which is (unfortunately) conditionally set, and doing getattr(self, '_is_coroutine', False); presumably it's slightly faster the way you've done it by adding another attribute?

I'd spotted this a while back too, but I didn't know enough about how the machinery of async and ASGI works to say for certain that the wrapping up of callables into a get_response would always be static after init. So I'm glad you're pushing it, where I was too uncertain :)

Great minds think alike!

When I was looking at it, I was thinking about re-using the _is_coroutine attribute which is (unfortunately) conditionally set, and doing getattr(self, '_is_coroutine', False); presumably it's slightly faster the way you've done it by adding another attribute?

Absolutely right, I missed that, and have updated to use it.

We can see asyncio.iscoroutine checks the attribute to be its special object, so None seems like a legit alternative: https://github.com/python/cpython/blob/e9898bf153d26059261ffef11f7643ae991e2a4c/Lib/asyncio/coroutines.py#L21-L24

This is where we find folks dynamically munging middleware functions. 😜 (I agree that's not expected, so the change should be OK.)

This would already be broken, as async_check() is not rerun