Inital commit

2026-07-29 01:00:10 -05:00
commit 23e8ea90e4
3301 changed files with 1376308 additions and 0 deletions
@@ -0,0 +1,100 @@
+#!/usr/bin/env python3
+"""
+MCP server (NDJSON JSON-RPC over stdio) that spawns a long-lived grandchild which inherits
+this process's stdin/stdout/stderr and keeps them open.
+
+This reproduces the reader-teardown deadlock: killing the direct MCP child (SIGKILL, which is
+all subprocess_terminate() does) does NOT close the stdout/stderr pipe write ends, because the
+grandchild still holds them. A server that reads those pipes with a blocking read would then
+wait forever for an EOF that never arrives, hanging teardown (both warmup shutdown at startup
+and process shutdown). The polled, running-aware reader must exit regardless.
+"""
+import json
+import os
+import subprocess
+import sys
+
+# Spawn a grandchild that inherits our std handles (fds 0/1/2 = the MCP pipes) and lives well
+# past any teardown in the tests. We do NOT redirect its stdio, so it keeps the pipe write ends
+# open even after this process is killed.
+subprocess.Popen([sys.executable, "-c", "import time; time.sleep(30)"])
+
+TOOLS = [
+    {
+        "name": "echo",
+        "description": "Echo back the input message",
+        "inputSchema": {
+            "type": "object",
+            "properties": {"message": {"type": "string", "description": "Message to echo"}},
+            "required": ["message"],
+        },
+    }
+]
+
+
+def handle_initialize(params, req_id):
+    return {
+        "jsonrpc": "2.0",
+        "id": req_id,
+        "result": {
+            "protocolVersion": "2024-11-05",
+            "capabilities": {"tools": {}},
+            "serverInfo": {"name": "grandchild-test", "version": "1.0"},
+        },
+    }
+
+
+def handle_tools_list(params, req_id):
+    return {"jsonrpc": "2.0", "id": req_id, "result": {"tools": TOOLS}}
+
+
+def handle_tools_call(params, req_id):
+    if params.get("name") == "echo":
+        message = params.get("arguments", {}).get("message", "")
+        return {
+            "jsonrpc": "2.0",
+            "id": req_id,
+            "result": {"content": [{"type": "text", "text": f"echo: {message}"}]},
+        }
+    return {"jsonrpc": "2.0", "id": req_id, "error": {"code": -32602, "message": "Unknown tool"}}
+
+
+HANDLERS = {
+    "initialize": handle_initialize,
+    "tools/list": handle_tools_list,
+    "tools/call": handle_tools_call,
+}
+
+
+def main():
+    sys.stdout = os.fdopen(sys.stdout.fileno(), "w", buffering=1)
+    sys.stderr = os.fdopen(sys.stderr.fileno(), "w", buffering=1)
+
+    for line in sys.stdin:
+        line = line.strip()
+        if not line:
+            continue
+        try:
+            request = json.loads(line)
+        except json.JSONDecodeError:
+            continue
+
+        method = request.get("method")
+        req_id = request.get("id")
+        params = request.get("params", {})
+
+        if req_id is None:
+            continue  # notification, no response
+
+        handler = HANDLERS.get(method)
+        if handler:
+            response = handler(params, req_id)
+        else:
+            response = {"jsonrpc": "2.0", "id": req_id, "error": {"code": -32601, "message": f"Method not found: {method}"}}
+
+        sys.stdout.write(json.dumps(response) + "\n")
+        sys.stdout.flush()
+
+
+if __name__ == "__main__":
+    main()