python-starlette fails to build with Python 3.14.0a5.

__________________________ test_wsgi_post[asyncio] ____________________________

test_client_factory = functools.partial(<class 'starlette.testclient.TestClient'>, backend='asyncio', backend_options={})

    def test_wsgi_post(test_client_factory: TestClientFactory) -> None:
        app = WSGIMiddleware(echo_body)
        client = test_client_factory(app)
        response = client.post("/", json={"example": 123})
        assert response.status_code == 200
>       assert response.text == '{"example":123}'
E       assert '{"example": 123}' == '{"example":123}'
E         
E         - {"example":123}
E         + {"example": 123}
E         ?            +

tests/middleware/test_wsgi.py:81: AssertionError
_____________________________ test_wsgi_post[trio] _____________________________

test_client_factory = functools.partial(<class 'starlette.testclient.TestClient'>, backend='trio', backend_options={})

    def test_wsgi_post(test_client_factory: TestClientFactory) -> None:
        app = WSGIMiddleware(echo_body)
        client = test_client_factory(app)
        response = client.post("/", json={"example": 123})
        assert response.status_code == 200
>       assert response.text == '{"example":123}'
E       assert '{"example": 123}' == '{"example":123}'
E         
E         - {"example":123}
E         + {"example": 123}
E         ?            +

tests/middleware/test_wsgi.py:81: AssertionError
__________________________ test_request_body[asyncio] __________________________

test_client_factory = functools.partial(<class 'starlette.testclient.TestClient'>, backend='asyncio', backend_options={})

    def test_request_body(test_client_factory: TestClientFactory) -> None:
        async def app(scope: Scope, receive: Receive, send: Send) -> None:
            request = Request(scope, receive)
            body = await request.body()
            response = JSONResponse({"body": body.decode()})
            await response(scope, receive, send)
    
        client = test_client_factory(app)
    
        response = client.get("/")
        assert response.json() == {"body": ""}
    
        response = client.post("/", json={"a": "123"})
>       assert response.json() == {"body": '{"a":"123"}'}
E       assert {'body': '{"a": "123"}'} == {'body': '{"a":"123"}'}
E         
E         Differing items:
E         {'body': '{"a": "123"}'} != {'body': '{"a":"123"}'}
E         
E         Full diff:
E           {
E         -     'body': '{"a":"123"}',...
E         
E         ...Full output truncated (3 lines hidden), use '-vv' to show

tests/test_requests.py:95: AssertionError
_________________________ test_request_stream[asyncio] _________________________

test_client_factory = functools.partial(<class 'starlette.testclient.TestClient'>, backend='asyncio', backend_options={})

    def test_request_stream(test_client_factory: TestClientFactory) -> None:
        async def app(scope: Scope, receive: Receive, send: Send) -> None:
            request = Request(scope, receive)
            body = b""
            async for chunk in request.stream():
                body += chunk
            response = JSONResponse({"body": body.decode()})
            await response(scope, receive, send)
    
        client = test_client_factory(app)
    
        response = client.get("/")
        assert response.json() == {"body": ""}
    
        response = client.post("/", json={"a": "123"})
>       assert response.json() == {"body": '{"a":"123"}'}
E       assert {'body': '{"a": "123"}'} == {'body': '{"a":"123"}'}
E         
E         Differing items:
E         {'body': '{"a": "123"}'} != {'body': '{"a":"123"}'}
E         
E         Full diff:
E           {
E         -     'body': '{"a":"123"}',...
E         
E         ...Full output truncated (3 lines hidden), use '-vv' to show

tests/test_requests.py:116: AssertionError
___________________________ test_request_body[trio] ____________________________

test_client_factory = functools.partial(<class 'starlette.testclient.TestClient'>, backend='trio', backend_options={})

    def test_request_body(test_client_factory: TestClientFactory) -> None:
        async def app(scope: Scope, receive: Receive, send: Send) -> None:
            request = Request(scope, receive)
            body = await request.body()
            response = JSONResponse({"body": body.decode()})
            await response(scope, receive, send)
    
        client = test_client_factory(app)
    
        response = client.get("/")
        assert response.json() == {"body": ""}
    
        response = client.post("/", json={"a": "123"})
>       assert response.json() == {"body": '{"a":"123"}'}
E       assert {'body': '{"a": "123"}'} == {'body': '{"a":"123"}'}
E         
E         Differing items:
E         {'body': '{"a": "123"}'} != {'body': '{"a":"123"}'}
E         
E         Full diff:
E           {
E         -     'body': '{"a":"123"}',...
E         
E         ...Full output truncated (3 lines hidden), use '-vv' to show

tests/test_requests.py:95: AssertionError
__________________________ test_request_stream[trio] ___________________________

test_client_factory = functools.partial(<class 'starlette.testclient.TestClient'>, backend='trio', backend_options={})

    def test_request_stream(test_client_factory: TestClientFactory) -> None:
        async def app(scope: Scope, receive: Receive, send: Send) -> None:
            request = Request(scope, receive)
            body = b""
            async for chunk in request.stream():
                body += chunk
            response = JSONResponse({"body": body.decode()})
            await response(scope, receive, send)
    
        client = test_client_factory(app)
    
        response = client.get("/")
        assert response.json() == {"body": ""}
    
        response = client.post("/", json={"a": "123"})
>       assert response.json() == {"body": '{"a":"123"}'}
E       assert {'body': '{"a": "123"}'} == {'body': '{"a":"123"}'}
E         
E         Differing items:
E         {'body': '{"a": "123"}'} != {'body': '{"a":"123"}'}
E         
E         Full diff:
E           {
E         -     'body': '{"a":"123"}',...
E         
E         ...Full output truncated (3 lines hidden), use '-vv' to show

https://docs.python.org/3.14/whatsnew/3.14.html

For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.14/fedora-rawhide-x86_64/08716724-python-starlette/

For all our attempts to build python-starlette with Python 3.14, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.14/package/python-starlette/

Testing and mass rebuild of packages is happening in copr.
You can follow these instructions to test locally in mock if your package builds with Python 3.14:
https://copr.fedorainfracloud.org/coprs/g/python/python3.14/

Let us know here if you have any questions.

Python 3.14 is planned to be included in Fedora 43.
To make that update smoother, we're building Fedora packages with all pre-releases of Python 3.14.
A build failure prevents us from testing all dependent packages (transitive [Build]Requires),
so if this package is required a lot, it's important for us to get it fixed soon.

We'd appreciate help from the people who know this package best,
but if you don't want to work on this now, let us know so we can try to work around it on our side.