python type_error ai_generated true

TypeError: object NoneType can't be used in 'await' expression

ID: python/fastapi-await-none-coroutine

Also available as: JSON · Markdown · 中文
80%Fix Rate
85%Confidence
0Evidence
2024-12-15First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.x active — — —

Root Cause

An async route awaits a call that is actually synchronous (e.g. a sync DB driver or a function returning None).

generic

中文

异步路由 await 了一个实际上是同步的调用（例如同步数据库驱动或返回 None 的函数）。

Workarounds

  1. 88% success 
    Use an async driver or run sync in a threadpool:
from starlette.concurrency import run_in_threadpool
result = await run_in_threadpool(sync_fn)
  2. 90% success 
    Remove await when calling a synchronous function.

Dead Ends

Common approaches that don't work:

  1. 60% fail

    Fixes this call but blocks the event loop for other requests.

  2. 85% fail

    Doesn't make the awaited object awaitable.