fix(bedrock): consume orphaned task exception on stream cancellation#2269
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AnnasMazhar wants to merge 1 commit intostrands-agents:mainfrom
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fix(bedrock): consume orphaned task exception on stream cancellation#2269AnnasMazhar wants to merge 1 commit intostrands-agents:mainfrom
AnnasMazhar wants to merge 1 commit intostrands-agents:mainfrom
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When a consumer cancels, breaks from, or times out on BedrockModel.stream, the internal asyncio.Task wrapping asyncio.to_thread is never awaited. If boto3 eventually raises, asyncio emits 'Task exception was never retrieved'. Add a done-callback on the unhappy path that retrieves the exception, silencing the warning without interrupting the background thread. Resolves: strands-agents#2266
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Motivation
When a consumer cancels, breaks from, or times out on
BedrockModel.stream, the internalasyncio.Taskwrappingasyncio.to_threadis never awaited. If boto3 eventually raises (e.g.,ReadTimeoutErrorafterread_timeout), asyncio emits "Task exception was never retrieved" — polluting application logs across three common usage patterns:asyncio.wait_for,async for ... break, and client disconnects in streaming HTTP handlers.The happy path already awaits the task. The unhappy path (any
BaseExceptioninterrupting the yield loop) leaves it orphaned.Resolves: #2266
Public API Changes
No public API changes. Internal cleanup only —
BedrockModel.streamnow ensures the background task's exception is consumed on all exit paths via a done-callback.Checked
AnthropicModel.streamandOpenAIModel.stream— neither usesasyncio.create_taskorasyncio.to_thread, so this pattern is unique to the Bedrock provider.