Subprocess kill win32

RELEASE.md

@@ -11,3 +11,5 @@ Create a GitHub release via UI with the tag being `vX.Y.Z` where `X.Y.Z` is the
 and the release title being the same. Then ask someone to review the release.
 
 The package version will be set automatically from the tag.
+
+

pyproject.toml

@@ -31,6 +31,7 @@ dependencies = [
     "sse-starlette>=1.6.1",
     "pydantic-settings>=2.5.2",
     "uvicorn>=0.23.1; sys_platform != 'emscripten'",
+    "psutil>=5.9.0",
     "jsonschema>=4.20.0",
 ]
 

src/mcp/client/stdio/win32.py

@@ -8,7 +8,7 @@
 from pathlib import Path
 from typing import BinaryIO, TextIO, cast
 
-import anyio
+import psutil
 from anyio import to_thread
 from anyio.abc import Process
 from anyio.streams.file import FileReadStream, FileWriteStream
@@ -61,6 +61,7 @@ def __init__(self, popen_obj: subprocess.Popen[bytes]):
         self.stdin_raw = popen_obj.stdin  # type: ignore[assignment]
         self.stdout_raw = popen_obj.stdout  # type: ignore[assignment]
         self.stderr = popen_obj.stderr  # type: ignore[assignment]
+        self.pid = popen_obj.pid
 
         self.stdin = FileWriteStream(cast(BinaryIO, self.stdin_raw)) if self.stdin_raw else None
         self.stdout = FileReadStream(cast(BinaryIO, self.stdout_raw)) if self.stdout_raw else None
@@ -162,6 +163,22 @@ async def create_windows_process(
 
 
 async def terminate_windows_process(process: Process | FallbackProcess):
+    """
+    Terminate a process and subprocesses.
+    """
+    try:
+        parent = psutil.Process(process.pid)
+    except psutil.NoSuchProcess:
+        return
+    except Exception:
+        pass  # Optionally log the exception
+    parent = psutil.Process(process.pid)
+    children = parent.children(recursive=True)
+    await terminate_psutil_process(children)
+    await terminate_psutil_process([parent])
+
+
+async def terminate_psutil_process(processes: list[psutil.Process]):
     """
     Terminate a Windows process.
 
@@ -173,10 +190,19 @@ async def terminate_windows_process(process: Process | FallbackProcess):
     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()
+    for process in processes:
+        try:
+            process.terminate()  # Send SIGTERM (or equivalent on Windows)
+        except psutil.NoSuchProcess:
+            pass
+        except Exception:
+            pass
+    # Allow some time for children to terminate gracefully
+    _, alive = psutil.wait_procs(processes, timeout=2.0)
+    for child in alive:
+        try:
+            child.kill()  # Force kill if still alive
+        except psutil.NoSuchProcess:
+            pass  # Already gone
+        except Exception:
+            pass