Lifespan example with state throws "The server does not support "state" in the lifespan scope." error

[RoyWiggins]

Hi,

The mechanism described here where the lifespan can yield a dictionary into app.state produces an error for me on startup:

INFO:     Started server process [716821]
INFO:     Waiting for application startup.
ERROR:    Traceback (most recent call last):
  File "/opt/mercure/env/lib/python3.10/site-packages/starlette/routing.py", line 696, in lifespan
    raise RuntimeError('The server does not support "state" in the lifespan scope.')
RuntimeError: The server does not support "state" in the lifespan scope.

ERROR:    Application startup failed. Exiting.

This is the exact code that I'm running under uvicorn (identical with the example), with starlette==0.38.5, uvicorn == 0.16.0 and httpx in a fresh virtualenv in python3.10:

import contextlib
from typing import AsyncIterator, TypedDict

import httpx
from starlette.applications import Starlette
from starlette.requests import Request
from starlette.responses import PlainTextResponse
from starlette.routing import Route

class State(TypedDict):
    http_client: httpx.AsyncClient


@contextlib.asynccontextmanager
async def lifespan(app: Starlette) -> AsyncIterator[State]:
    async with httpx.AsyncClient() as client:
        yield {"http_client": client}


async def homepage(request: Request) -> PlainTextResponse:
    client = request.state.http_client
    response = await client.get("https://www.example.com")
    return PlainTextResponse(response.text)


app = Starlette(
    lifespan=lifespan,
    routes=[Route("/", homepage)]
)

A minimal example:

from starlette.applications import Starlette

async def lifespan(app):
    yield {}

app = Starlette(lifespan=lifespan)

[RoyWiggins]

Oh, fixing this is just a matter of updating uvicorn to the latest version (0.30.6).