Python / FastAPI: RuntimeWarning: coroutine '...' was never awaited
RuntimeWarning: coroutine 'fetch_user_data' was never awaited
Enable tracemalloc to get the object allocation traceback
Immediate Remediation
python
# Ensure async coroutine call is prefixed with await:
@app.get("/users/{user_id}")
async def get_user(user_id: str):
# Fix: Added await keyword before async function call
user_data = await fetch_user_data(user_id)
return {"user": user_data}Root Cause Analysis
An asynchronous function (defined with async def) was invoked synchronously without the await keyword, returning an unexecuted coroutine object instead of its return value.
Verification & Guardrails
- If running in synchronous def endpoints, use asyncio.run(coroutine) or refactor endpoint to async def.
- Run python with -X dev to get exact allocation line tracebacks.
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