python runtime_error ai_generated true

asyncio 异常：任务中引发了 CancelledError

asyncio.exceptions.CancelledError: CancelledError raised in task

ID: python/asyncio-task-cancellation-error

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80%修复率
86%置信度
0证据数
2025-06-15首次发现

版本兼容性

版本状态引入弃用备注
3.8 active — — —
3.9 active — — —

根因分析

任务被外部取消（例如通过 task.cancel()），且未处理取消操作，导致其传播。

English

A task was cancelled externally (e.g., via task.cancel()), and the cancellation was not handled, causing it to propagate.

generic

解决方案

  1. 90% 成功率 Catch CancelledError and perform cleanup, then re-raise 
    try:
    await long_running_coro()
except asyncio.CancelledError:
    # cleanup resources
    raise
  2. 85% 成功率 Use asyncio.shield() to protect critical sections 
    await asyncio.shield(critical_coro())

无效尝试

常见但无效的做法:

  1. Catching all exceptions except CancelledError 70% 失败

    CancelledError is a subclass of BaseException, so it may not be caught by except Exception.

  2. Ignoring cancellation and continuing execution 50% 失败

    The event loop may be shutting down, and ignoring cancellation can cause resource leaks or hangs.