If the lifetime is frozen, the app will not respond to the Ctrl + C

[suiseriff]

Initial Checks

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Discussion Link

https://github.com/Kludex/uvicorn/discussions/2716

Description

When the application hangs during its lifespan, it becomes completely unresponsive to the Ctrl+C command (SIGINT), preventing a graceful shutdown. This forces users to resort to using the kill -9 command.

Example Code

import asyncio
from collections.abc import AsyncIterator
from contextlib import asynccontextmanager

import uvicorn
from fastapi import FastAPI

@asynccontextmanager
async def lifespan(_: FastAPI) -> AsyncIterator[None]:
    await asyncio.sleep(5000)  # Simulates hanging operation
    yield

def create_app() -> FastAPI:
    return FastAPI(lifespan=lifespan)

if __name__ == "__main__":
    uvicorn.run(create_app(), host="0.0.0.0", port=8000)

Python, Uvicorn & OS Version

Running uvicorn 0.38.0 with CPython 3.12.11 on Linux
fastapi: 0.121.0
OS: Arch Linux x86_64
Kernel: 6.17.7-arch1-1