Fix process termination in stdio client

Github-Issue: #391

Author: ashrobertsdragon

src/mcp/client/stdio/__init__.py

@@ -6,17 +6,16 @@
 
 import anyio
 import anyio.lowlevel
-from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
+from anyio.streams.memory import (
+    MemoryObjectReceiveStream,
+    MemoryObjectSendStream,
+)
 from anyio.streams.text import TextReceiveStream
 from pydantic import BaseModel, Field
 
 import mcp.types as types
 
-from .win32 import (
-    create_windows_process,
-    get_windows_executable_command,
-    terminate_windows_process,
-)
+from .win32 import create_windows_process, get_windows_executable_command
 
 # Environment variables to inherit by default
 DEFAULT_INHERITED_ENV_VARS = (
@@ -173,10 +172,9 @@ async def stdin_writer():
             yield read_stream, write_stream
         finally:
             # Clean up process to prevent any dangling orphaned processes
-            if sys.platform == "win32":
-                await terminate_windows_process(process)
-            else:
-                process.terminate()
+            tg.cancel_scope.cancel()
+            process.terminate()
+            await process.wait()
 
 
 def _get_executable_command(command: str) -> str:

src/mcp/client/stdio/win32.py

@@ -9,7 +9,6 @@
 from typing import TextIO
 
 import anyio
-from anyio.abc import Process
 
 
 def get_windows_executable_command(command: str) -> str:
@@ -86,24 +85,3 @@ async def create_windows_process(
             [command, *args], env=env, stderr=errlog, cwd=cwd
         )
         return process
-
-
-async def terminate_windows_process(process: Process):
-    """
-    Terminate a Windows process.
-
-    Note: On Windows, terminating a process with process.terminate() doesn't
-    always guarantee immediate process termination.
-    So we give it 2s to exit, or we call process.kill()
-    which sends a SIGKILL equivalent signal.
-
-    Args:
-        process: The process to terminate
-    """
-    try:
-        process.terminate()
-        with anyio.fail_after(2.0):
-            await process.wait()
-    except TimeoutError:
-        # Force kill if it doesn't terminate
-        process.kill()