fix: fix athrow() RuntimeError on streaming responses#912
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This pull request replaces the aconnect_sse utility with a custom _SSEEventSource class to prevent async generator leaks and associated RuntimeError during event-loop shutdown. An integration test has been added to ensure proper cleanup. Reviewer feedback recommends using httpx.Headers for more robust header management and updating a placeholder issue reference in the test file.
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
🧪 Code Coverage (vs
|
| Base | PR | Delta | |
|---|---|---|---|
| src/a2a/client/transports/http_helpers.py | 94.64% | 94.44% | 🔴 -0.20% |
| src/a2a/server/tasks/task_manager.py | 97.44% | 98.29% | 🟢 +0.85% |
| Total | 91.57% | 91.59% | 🟢 +0.02% |
Generated by coverage-comment.yml
sokoliva
approved these changes
Mar 27, 2026
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When the server sends a
Messageevent in the SSE stream,_process_streamdoes an early return abandoning the generator chain while the SSE connection is still open.send_http_stream_requestyields insideasync with aconnect_sse(...).aconnect_sse(from httpx-sse) is an@asynccontextmanager.During event loop shutdown,
shutdown_asyncgenstries to finalize all tracked generators independently - twoathrow()calls hit the same chain, producing theRuntimeError.Replace
aconnect_ssewith_SSEEventSource- a class-based async context manager that callshttpx_client.send(..., stream=True)directly andresponse.aclose()in__aexit__.Added test fails without a fix: https://github.com/a2aproject/a2a-python/actions/runs/23648762100/job/68887648853.
Fixes #911