python runtime_error ai_generated true

RuntimeError: Event loop is closed

ID: python/asyncio-event-loop-closed

Also available as: JSON · Markdown · 中文
80%Fix Rate
85%Confidence
0Evidence
2024-02-15First Seen

Version Compatibility

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

Root Cause

Attempting to use an asyncio event loop after it has been explicitly closed, often due to calling loop.close() prematurely or reusing a loop after shutdown.

generic

中文

在事件循环已被显式关闭后尝试使用它，通常是因为过早调用 loop.close() 或在关闭后重用循环。

Workarounds

  1. 95% success Use asyncio.run() for top-level entry point to avoid manual loop management 
    async def main(): await some_coroutine(); asyncio.run(main())
  2. 85% success Check if loop is closed before using it, and create a new one if needed 
    if loop.is_closed(): loop = asyncio.new_event_loop(); asyncio.set_event_loop(loop)

Dead Ends

Common approaches that don't work:

  1. Recreating the loop with asyncio.new_event_loop() without setting it as current 70% fail

    The new loop is not set as the current loop, so asyncio.get_event_loop() still returns a closed loop.

  2. Ignoring the error and continuing execution 90% fail

    The closed loop cannot process coroutines, leading to hangs or crashes later.

  3. Using loop.run_forever() after loop.close() 100% fail

    A closed loop cannot be restarted; run_forever() raises RuntimeError.