AIO HTTP/2 writer task raises unhandled AWS_ERROR_HTTP_STREAM_HAS_COMPLETED during normal shutdown

[pgrayy]

Describe the bug

Closing an HTTP/2 bidirectional request through the client's async context managers can leave AIOHttp2ClientStream._set_request_body_generator() with an unobserved exception. Its final end-stream write raises AWS_ERROR_HTTP_STREAM_HAS_COMPLETED, producing:

Task exception was never retrieved

Regression Issue

Unchecked — I have not established an earlier working version.

Expected Behavior

Normal stream/client shutdown should not produce an unhandled asyncio task exception. The request-writer task should be observed, and stream completion during its final end-stream write should be handled as part of shutdown.

Current Behavior

Task exception was never retrieved
future: <Task ... coro=<AIOHttp2ClientStream._set_request_body_generator() ...>
Traceback (most recent call last):
  File "awscrt/aio/http.py", line 532, in _set_request_body_generator
    await self._write_data(None, True)
  File "awscrt/aio/http.py", line 524, in _write_data
    _awscrt.http2_client_stream_write_data(...)
RuntimeError: 2080 (AWS_ERROR_HTTP_STREAM_HAS_COMPLETED):
HTTP-stream has completed, action cannot be performed.

Reproduction Steps

Requires AWS credentials and access to Amazon Nova Sonic.

import asyncio
import gc
import json
import os
import uuid

from aws_sdk_bedrock_runtime.client import AsyncBedrockRuntimeClient
from aws_sdk_bedrock_runtime.config import AsyncBedrockRuntimeConfig
from aws_sdk_bedrock_runtime.models import (
    BidirectionalInputPayloadPart,
    InvokeModelWithBidirectionalStreamInputChunk,
    InvokeModelWithBidirectionalStreamOperationInput,
)
from smithy_http.aio.crt import AWSCRTHTTPClient


async def send(stream, event):
    payload = json.dumps({"event": event}).encode()
    await stream.input_stream.send(
        InvokeModelWithBidirectionalStreamInputChunk(
            value=BidirectionalInputPayloadPart(bytes_=payload)
        )
    )


async def main():
    config = await AsyncBedrockRuntimeConfig.resolve(
        region=os.getenv("AWS_REGION", "us-east-1"),
        transport=AWSCRTHTTPClient(),
    )
    async with AsyncBedrockRuntimeClient(config=config) as client:
        stream = await client.invoke_model_with_bidirectional_stream(
            InvokeModelWithBidirectionalStreamOperationInput(
                model_id="amazon.nova-2-sonic-v1:0"
            )
        )
        async with stream:
            prompt = str(uuid.uuid4())
            await send(stream, {"sessionStart": {"inferenceConfiguration": {}}})
            await send(
                stream,
                {
                    "promptStart": {
                        "promptName": prompt,
                        "textOutputConfiguration": {"mediaType": "text/plain"},
                        "audioOutputConfiguration": {
                            "mediaType": "audio/lpcm",
                            "sampleRateHertz": 16000,
                            "sampleSizeBits": 16,
                            "channelCount": 1,
                            "voiceId": "matthew",
                            "encoding": "base64",
                            "audioType": "SPEECH",
                        },
                    }
                },
            )
            await send(stream, {"promptEnd": {"promptName": prompt}})
            await send(stream, {"connectionEnd": {}})

    gc.collect()  # Make reporting of the unobserved task deterministic.
    await asyncio.sleep(0.1)


asyncio.run(main())

Possible Solution

AIOHttpClientStreamUnified creates the request-writer task with create_task() but does not subsequently observe it. The stream should retain and retrieve/await that task during shutdown, handling code 2080 when the stream has already completed.

Additional Information/Context

• Reproduces without an application framework, using the generated client's supported async context managers.
• aws-sdk-bedrock-runtime==0.11.0
• smithy-http==0.5.0
• Related to, but distinct from, aws/aws-sdk-python#13, which reports an InvalidStateError on output-stream close.

aws-crt-python version used

0.32.2

Python version used

3.12.13

Operating System and version

macOS 26.6.2