Incorrect typing on AsyncResponse.iter_content()

[judilsteve]

One must run async for chunk in await async_response.iter_content() (which conflicts with the type hints provided for AsyncResponse.iter_content()) instead of the expected async for chunk in async_response.iter_content().

Expected Result

Content of the HTTP response to be printed in chunks to stdout.

Actual Result

Exception:

Traceback (most recent call last):
  File "<redacted>/test.py", line 10, in <module>
    if __name__ == '__main__': asyncio.run(_main())
                               ^^^^^^^^^^^^^^^^^^^^
  File "/home/james/.pyenv/versions/3.12.1/lib/python3.12/asyncio/runners.py", line 194, in run
    return runner.run(main)
           ^^^^^^^^^^^^^^^^
  File "/home/james/.pyenv/versions/3.12.1/lib/python3.12/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/james/.pyenv/versions/3.12.1/lib/python3.12/asyncio/base_events.py", line 684, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File "<redacted>/test.py", line 7, in _main
    async for chunk in resp.iter_content():
TypeError: 'async for' requires an object with __aiter__ method, got coroutine

Reproduction Steps

import asyncio
from niquests import AsyncSession

async def _main():
    async with AsyncSession() as session:
        resp = await session.get('https://github.com/jawah/niquests', stream=True)
        async for chunk in resp.iter_content():
            print(chunk)

if __name__ == '__main__': asyncio.run(_main())

System Information

$ python -m niquests.help

{
  "charset_normalizer": {
    "version": "3.4.0"
  },
  "http1": {
    "h11": "0.14.0"
  },
  "http2": {
    "jh2": "5.0.4"
  },
  "http3": {
    "enabled": true,
    "qh3": "1.2.1"
  },
  "idna": {
    "version": "3.10"
  },
  "implementation": {
    "name": "CPython",
    "version": "3.12.1"
  },
  "niquests": {
    "version": "3.11.1"
  },
  "ocsp": {
    "enabled": true
  },
  "platform": {
    "release": "5.15.153.1-microsoft-standard-WSL2",
    "system": "Linux"
  },
  "system_ssl": {
    "version": "300000d0"
  },
  "urllib3.future": {
    "cohabitation_version": null,
    "version": "2.12.900"
  },
  "wassima": {
    "certifi_fallback": false,
    "enabled": true,
    "version": "1.1.5"
  }
}

Workaround

import asyncio
from niquests import AsyncSession
from typing import cast, Coroutine, AsyncGenerator

async def _main():
    async with AsyncSession() as session:
        resp = await session.get('https://github.com/jawah/niquests', stream=True)
        async for chunk in await cast(Coroutine[None, None, AsyncGenerator[bytes, None]], resp.iter_content()):
            print(chunk)

if __name__ == '__main__': asyncio.run(_main())

[Ousret]

It's true, something isn't right. But it is not what you think it is.
I suspect there's a bug (some edge case) that bring this bad UX. It does not seems to be something we can deal with within Niquests.

If you have a (rather clean, without breakage) solution that we can apply that makes both modern IDEs and mypy happy with, we'll proceed.

async def reproducer() -> typing.AsyncGenerator[bytes, None]:
    async def gen() -> typing.AsyncGenerator[bytes, None]:
        yield b"foo"
        yield b"bar"
    return gen()

So there you have to await reproducer() as their is no yield within reproducer. This minimal code does not confuse mypy or IDEs. But Niquests makes it glitch somehow, making it "okay" to not await the method.

We'll need a typing expert to investigate.

Regards,

[gremlation]

I'm experiencing the same problem with niquests==3.11.3:

async with niquests.AsyncSession() as session:
    response = await session.get(url, stream=True)
    async for chunk in await response.iter_content(chunk_size=4096):

This causes Pylance to generate the warning:

"AsyncGenerator[bytes, None]" is not awaitable
  "AsyncGenerator[bytes, None]" is incompatible with protocol "Awaitable[_T_co@Awaitable]"
    "__await__" is not present

Could this be reopened @Ousret ?

[Ousret]

Could you share the exact environment you are in? IDE version, Pylance version?
FWIW I have no issue with PyCharm + Mypy at all. There was one before 3.11.3 but not anymore.

Does Pylance have a issue tracker? If so could you ask for their expertise on that matter?

Regards,