Merge branch 'main' into feat/sep-2207

Author: wdawson

pyproject.toml

@@ -25,7 +25,7 @@ classifiers = [
     "Programming Language :: Python :: 3.14",
 ]
 dependencies = [
-    "anyio>=4.5",
+    "anyio>=4.9",
     "httpx>=0.27.1",
     "httpx-sse>=0.4",
     "pydantic>=2.12.0",

src/mcp/client/sse.py

@@ -160,3 +160,5 @@ async def post_writer(endpoint_url: str):
         finally:
             await read_stream_writer.aclose()
             await write_stream.aclose()
+            await read_stream.aclose()
+            await write_stream_reader.aclose()

src/mcp/client/streamable_http.py

@@ -577,3 +577,5 @@ def start_get_stream() -> None:
         finally:
             await read_stream_writer.aclose()
             await write_stream.aclose()
+            await read_stream.aclose()
+            await write_stream_reader.aclose()

src/mcp/client/websocket.py

@@ -38,11 +38,10 @@ async def websocket_client(
     write_stream: MemoryObjectSendStream[SessionMessage]
     write_stream_reader: MemoryObjectReceiveStream[SessionMessage]
 
-    read_stream_writer, read_stream = anyio.create_memory_object_stream(0)
-    write_stream, write_stream_reader = anyio.create_memory_object_stream(0)
-
     # Connect using websockets, requesting the "mcp" subprotocol
     async with ws_connect(url, subprotocols=[Subprotocol("mcp")]) as ws:
+        read_stream_writer, read_stream = anyio.create_memory_object_stream(0)
+        write_stream, write_stream_reader = anyio.create_memory_object_stream(0)
 
         async def ws_reader():
             """Reads text messages from the WebSocket, parses them as JSON-RPC messages,
@@ -68,7 +67,13 @@ async def ws_writer():
                     msg_dict = session_message.message.model_dump(by_alias=True, mode="json", exclude_unset=True)
                     await ws.send(json.dumps(msg_dict))
 
-        async with anyio.create_task_group() as tg:
+        async with (
+            read_stream_writer,
+            read_stream,
+            write_stream,
+            write_stream_reader,
+            anyio.create_task_group() as tg,
+        ):
             # Start reader and writer tasks
             tg.start_soon(ws_reader)
             tg.start_soon(ws_writer)

src/mcp/os/win32/utilities.py

@@ -123,6 +123,11 @@ def pid(self) -> int:
         """Return the process ID."""
         return self.popen.pid
 
+    @property
+    def returncode(self) -> int | None:
+        """Return the exit code, or ``None`` if the process has not yet terminated."""
+        return self.popen.returncode
+
 
 # ------------------------
 # Updated function