httpx.Response.stream does not detect inital EOF

[D1-3105]

Version: 0.26.0
Steps to reproduce:
0. Create httpx.AsyncClient instance

1. Send POST request to some web-server which responds with EOF as body with some status code different to 204 (I used webhook.site)
2. Call async for _ in response.stream
3. The httpx stream is deadlocked, while underlying tcp connection is closed.

Full snippet:

import asyncio
import sys
import httpx
import time

last_timer = time.perf_counter()
async def call_me():
    client = httpx.AsyncClient()

    last_status_code = None
    global last_timer
    while last_status_code != 429:
        response = await client.post("https://webhook.site/7c7048f3-44ac-4cac-8450-96031dd41a0a", timeout=httpx.Timeout(5))
        try:
            last_status_code = response.status_code
            print(f"{last_status_code=}")
            print(f"{response.stream._stream._httpcore_stream._closed=}")
            async for i in response.stream:
                print(i, flush=True)
        except Exception as e:
            print(e, flush=True)
        finally:
            await response.aclose()

try:
    asyncio.run(call_me())
finally:
    print(time.perf_counter() - last_timer)

My output:

$ python3 test.py
last_status_code=200
response.stream._stream._httpcore_stream._closed=True
^C18.568296384997666

As you can see, the httpx stream was waiting for nothing.

[lovelydinosaur]

You're using client.post(...) so the entire response has already been streamed and is available in response.content.
Use with client.stream(...) as response for streaming responses.

Tho yes, there's some possible tighter API constraints we could put in place there. 🤔

[D1-3105]

I feel if you allow devs to iter through something than you have to raise StopIteration/StopAsyncIteration if the iterator exceeded. Also, if there is a content in response body - .stream method raises StopIteration as it is expected. I caught a few deadlocks because of this case (httpx.Timeout does not do a thing, as you can see).
Nevertheless, thanks for the proper way to iter streams, forgot about this func.

[lovelydinosaur]

Send POST request to some web-server which responds with EOF as body with some status code different to 204

Are you able to demo a little server or similar to test this against?
I'm only seeing properly formed 200 responses against that particular URL.

[D1-3105]

Send POST request to some web-server which responds with EOF as body with some status code different to 204

Are you able to demo a little server or similar to test this against? I'm only seeing properly formed 200 responses against that particular URL.

Could you please provide your output and version, I'd like to test with your environment.