python runtime_error ai_generated true

RuntimeError: Cannot run the event loop while another loop is running

ID: python/asyncio-loop-already-running-nested

Also available as: JSON · Markdown · 中文
80%Fix Rate
87%Confidence
0Evidence
2024-06-01First Seen

Version Compatibility

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

Root Cause

loop.run_until_complete() was called from inside a coroutine that is already executing on the same loop, causing nested loop execution which asyncio forbids.

generic

中文

在已运行于同一循环的协程内部调用了 loop.run_until_complete()，导致 asyncio 禁止的嵌套循环执行。

Workarounds

  1. 95% success 
    async def outer():
    # WRONG: loop.run_until_complete(inner())
    await inner()  # correct
  2. 88% success 
    result = await asyncio.to_thread(sync_blocking_fn, arg1, arg2)

Dead Ends

Common approaches that don't work:

  1. 90% fail

    get_event_loop returns the running loop; run_until_complete still raises.

  2. 85% fail

    The loop is still running; a yield point does not allow re-entrant run_until_complete.