Deprecate ServerState in the main module (#2581)

Author: Kludex

tests/protocols/test_http.py

@@ -14,8 +14,8 @@
 from uvicorn.config import WS_PROTOCOLS, Config
 from uvicorn.lifespan.off import LifespanOff
 from uvicorn.lifespan.on import LifespanOn
-from uvicorn.main import ServerState
 from uvicorn.protocols.http.h11_impl import H11Protocol
+from uvicorn.server import ServerState
 
 try:
     from uvicorn.protocols.http.httptools_impl import HttpToolsProtocol

tests/test_auto_detection.py

@@ -5,9 +5,9 @@
 
 from uvicorn.config import Config
 from uvicorn.loops.auto import auto_loop_setup
-from uvicorn.main import ServerState
 from uvicorn.protocols.http.auto import AutoHTTPProtocol
 from uvicorn.protocols.websockets.auto import AutoWebSocketsProtocol
+from uvicorn.server import ServerState
 
 try:
     importlib.import_module("uvloop")

tests/test_main.py

@@ -1,10 +1,12 @@
+import importlib
 import inspect
 import socket
 from logging import WARNING
 
 import httpx
 import pytest
 
+import uvicorn.server
 from tests.utils import run_server
 from uvicorn import Server
 from uvicorn._types import ASGIReceiveCallable, ASGISendCallable, Scope
@@ -113,3 +115,12 @@ async def test_exit_on_create_server_with_invalid_host() -> None:
         server = Server(config=config)
         await server.serve()
     assert exc_info.value.code == 1
+
+
+def test_deprecated_server_state_from_main() -> None:
+    with pytest.deprecated_call(
+        match="uvicorn.main.ServerState is deprecated, use uvicorn.server.ServerState instead."
+    ):
+        main = importlib.import_module("uvicorn.main")
+        server_state_cls = getattr(main, "ServerState")
+    assert server_state_cls is uvicorn.server.ServerState

uvicorn/main.py

@@ -6,6 +6,7 @@
 import platform
 import ssl
 import sys
+import warnings
 from configparser import RawConfigParser
 from typing import IO, Any, Callable
 
@@ -29,7 +30,7 @@
     LoopSetupType,
     WSProtocolType,
 )
-from uvicorn.server import Server, ServerState  # noqa: F401  # Used to be defined here.
+from uvicorn.server import Server
 from uvicorn.supervisors import ChangeReload, Multiprocess
 
 LEVEL_CHOICES = click.Choice(list(LOG_LEVELS.keys()))
@@ -587,5 +588,17 @@ def run(
         sys.exit(STARTUP_FAILURE)
 
 
+def __getattr__(name: str) -> Any:
+    if name == "ServerState":
+        warnings.warn(
+            "uvicorn.main.ServerState is deprecated, use uvicorn.server.ServerState instead.",
+            DeprecationWarning,
+        )
+        from uvicorn.server import ServerState
+
+        return ServerState
+    raise AttributeError(f"module {__name__} has no attribute {name}")
+
+
 if __name__ == "__main__":
     main()  # pragma: no cover