python runtime_error ai_generated true

RuntimeError: Task got Future attached to a different loop

ID: python/asyncio-task-got-future-different-loop

Also available as: JSON · Markdown · 中文
80%Fix Rate
88%Confidence
0Evidence
2024-03-27First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.8+ active — — —
3.9+ active — — —
3.10+ active — — —
3.11+ active — — —
3.12+ active — — —

Root Cause

A coroutine or Future created under one event loop was awaited on another loop, e.g. by calling asyncio.run() twice or mixing loop.run_until_complete() with asyncio.run().

generic

中文

在某个事件循环下创建的协程或 Future 被另一个循环 await，例如两次调用 asyncio.run() 或混用 loop.run_until_complete() 与 asyncio.run()。

Workarounds

  1. 95% success 
    loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
loop.run_until_complete(main())  # single entry point
  2. 90% success 
    # In Jupyter/IPython or uvicorn, just 'await main()'
# Do NOT call asyncio.run() inside an already-running loop

Dead Ends

Common approaches that don't work:

  1. 85% fail

    The Future object still references the original loop; identity mismatch remains.

  2. 80% fail

    ensure_future still binds to the current loop, not the Future's original loop.