Error of in-flight requests using streaming response

[gtsystem]

Hi, I'm trying to debug an issue that started showing up from httpx 0.20.
I created this mini example that is exposing the problem:

import json
import asyncio
import httpx

async def read_lines(client: httpx.AsyncClient):
    async with client.stream("GET", "https://httpbin.org/stream/10") as resp:
        async for line in resp.aiter_lines():
            yield json.loads(line)

async def main():
    client = httpx.AsyncClient()
    async for json_line in read_lines(client):
        print(json_line)
        break   # we interrupt reading the stream

    await client.aclose()

asyncio.run(main())

And it fails with

RuntimeError: The connection pool was closed while 1 HTTP requests/responses were still in-flight.

From my investigation it seems that resp.aclose() is called first (inside the context), but as it is asyncronous, before completing, the code reach async client.aclose() and the error is raised.

Adding await asyncio.sleep(0.1) before async client.aclose() resolve the issue.

Is it a bug or I'm doing something wrong? Any idea?

[guyskk]

Hi @gtsystem, it seems an asynchronous generators finalization problem, FYI: https://peps.python.org/pep-0525/#finalization

Close the generator manually can resolve the problem.

async def main():
    client = httpx.AsyncClient()
    agen = read_lines(client)
    async for json_line in agen:
        print(json_line)
        break  # we interrupt reading the stream
    await agen.aclose()  # --> close it manually
    await client.aclose()

[gtsystem]

Yes, it looks like this is solving the issue for me. Thanks!