python runtime_error ai_generated true

RuntimeWarning: coroutine 'sleep' was never awaited — did you mean time.sleep?

ID: python/asyncio-sleep-blocks-loop

Also available as: JSON · Markdown · 中文
80%Fix Rate
90%Confidence
0Evidence
2024-02-28First Seen

Version Compatibility

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

Root Cause

time.sleep() was called inside an async function, blocking the entire event loop instead of yielding control.

generic

中文

在异步函数中调用了 time.sleep()，阻塞了整个事件循环，而不是让出控制权。

Workarounds

  1. 98% success 
    Use asyncio.sleep:

import asyncio
await asyncio.sleep(1)
  2. 90% success 
    For CPU-bound work, offload to a thread:

await asyncio.to_thread(cpu_heavy_fn)
  3. 85% success 
    Enable asyncio debug mode to catch blocking calls:

asyncio.run(main(), debug=True)

Dead Ends

Common approaches that don't work:

  1. 90% fail

    Still blocks the loop, just for less time.

  2. 50% fail

    Works but wastes a thread for what asyncio.sleep does natively.

  3. 70% fail

    Overcomplicated; the blocking call still stalls that thread's loop.