Fix client API version bugs

viser/infra/_infra.py

@@ -14,7 +14,6 @@
     Callable,
     Dict,
     List,
-    Literal,
     NewType,
     Optional,
     Sequence,
@@ -32,6 +31,7 @@
 from rich import box, style
 from rich.panel import Panel
 from rich.table import Table
+from typing_extensions import Literal, assert_never
 from websockets.legacy.server import WebSocketServerProtocol
 
 from ._async_message_buffer import AsyncMessageBuffer, MessageWindow
@@ -134,7 +134,7 @@ def __init__(
         self._message_class = message_class
         self._http_server_root = http_server_root
         self._verbose = verbose
-        self._client_api_version = client_api_version
+        self._client_api_version: Literal[0, 1] = client_api_version
 
         self._thread_executor = ThreadPoolExecutor(max_workers=32)
 
@@ -332,7 +332,7 @@ async def _client_producer(
     websocket: WebSocketServerProtocol,
     client_id: ClientId,
     get_next: Callable[[], Awaitable[Message]],
-    client_api_version: int,
+    client_api_version: Literal[0, 1],
 ) -> None:
     """Infinite loop to send messages from a buffer to a single client."""
 
@@ -343,34 +343,38 @@ async def _client_producer(
             message_future = asyncio.ensure_future(get_next())
         outgoing = window.get_window_to_send()
         if outgoing is not None:
-            if client_api_version:
+            if client_api_version == 1:
                 serialized = msgpack.packb(
                     tuple(message.as_serializable_dict() for message in outgoing)
                 )
                 assert isinstance(serialized, bytes)
                 await websocket.send(serialized)
-            else:
+            elif client_api_version == 0:
                 for msg in outgoing:
                     await websocket.send(msg.as_serializable_dict())
+            else:
+                assert_never(client_api_version)
 
 
 async def _broadcast_producer(
     websocket: WebSocketServerProtocol,
     get_next_window: Callable[[], Awaitable[Sequence[Message]]],
-    client_api_version: int,
+    client_api_version: Literal[0, 1],
 ) -> None:
     """Infinite loop to broadcast windows of messages from a buffer."""
     while True:
         outgoing = await get_next_window()
-        if client_api_version:
+        if client_api_version == 1:
             serialized = msgpack.packb(
                 tuple(message.as_serializable_dict() for message in outgoing)
             )
             assert isinstance(serialized, bytes)
             await websocket.send(serialized)
-        else:
+        elif client_api_version == 0:
             for msg in outgoing:
                 await websocket.send(msg.as_serializable_dict())
+        else:
+            assert_never(client_api_version)
 
 
 async def _consumer(