Add compatibility imports from legacy package in __all__.

Supersedes #1400.

src/websockets/auth.py

@@ -1,4 +1,6 @@
 from __future__ import annotations
 
 # See #940 for why lazy_import isn't used here for backwards compatibility.
+# See #1400 for why listing compatibility imports in __all__ helps PyCharm.
 from .legacy.auth import *
+from .legacy.auth import __all__  # noqa: F401

src/websockets/client.py

@@ -38,10 +38,12 @@
 
 
 # See #940 for why lazy_import isn't used here for backwards compatibility.
+# See #1400 for why listing compatibility imports in __all__ helps PyCharm.
 from .legacy.client import *  # isort:skip  # noqa: I001
+from .legacy.client import __all__ as legacy__all__
 
 
-__all__ = ["ClientProtocol"]
+__all__ = ["ClientProtocol"] + legacy__all__
 
 
 class ClientProtocol(Protocol):

src/websockets/server.py

@@ -39,10 +39,12 @@
 
 
 # See #940 for why lazy_import isn't used here for backwards compatibility.
+# See #1400 for why listing compatibility imports in __all__ helps PyCharm.
 from .legacy.server import *  # isort:skip  # noqa: I001
+from .legacy.server import __all__ as legacy__all__
 
 
-__all__ = ["ServerProtocol"]
+__all__ = ["ServerProtocol"] + legacy__all__
 
 
 class ServerProtocol(Protocol):

tests/test_exports.py

@@ -1,24 +1,20 @@
 import unittest
 
 import websockets
+import websockets.auth
 import websockets.client
 import websockets.exceptions
-import websockets.legacy.auth
-import websockets.legacy.client
 import websockets.legacy.protocol
-import websockets.legacy.server
 import websockets.server
 import websockets.typing
 import websockets.uri
 
 
 combined_exports = (
-    websockets.legacy.auth.__all__
-    + websockets.legacy.client.__all__
-    + websockets.legacy.protocol.__all__
-    + websockets.legacy.server.__all__
+    websockets.auth.__all__
     + websockets.client.__all__
     + websockets.exceptions.__all__
+    + websockets.legacy.protocol.__all__
     + websockets.server.__all__
     + websockets.typing.__all__
     + websockets.uri.__all__