Fix orphaned lsp_server.py processes accumulating on Remote SSH hosts

bundled/tool/lsp_server.py

@@ -10,6 +10,7 @@
 import re
 import sys
 import sysconfig
+import threading
 import traceback
 from typing import Any, Optional, Sequence
 
@@ -601,5 +602,29 @@ def log_always(message: str) -> None:
 # *****************************************************
 # Start the server.
 # *****************************************************
+def _stdin_watchdog() -> None:
+    """Watch for stdin closure and exit if the parent process is gone."""
+    while True:
+        try:
+            if sys.stdin.closed:
+                os._exit(0)
+            # On Unix, select() on a closed pipe returns the fd as readable,
+            # and a subsequent read returns EOF. On Windows, just poll the closed flag.
+            if hasattr(__import__("select"), "select"):
+                readable, _, _ = __import__("select").select([sys.stdin], [], [], 5.0)
+                if readable:
+                    data = sys.stdin.read(1)
+                    if data == "":
+                        os._exit(0)
+            else:
+                __import__("time").sleep(5)
+                if sys.stdin.closed:
+                    os._exit(0)
+        except Exception:  # pylint: disable=broad-except
+            os._exit(0)
+
+
 if __name__ == "__main__":
+    watchdog = threading.Thread(target=_stdin_watchdog, daemon=True)
+    watchdog.start()
     LSP_SERVER.start_io()

src/common/server.ts

@@ -86,7 +86,9 @@ export async function restartServer(
 ): Promise<LanguageClient | undefined> {
     if (lsClient) {
         traceInfo(`Server: Stop requested`);
-        await lsClient.stop();
+        await lsClient.stop(2000).catch(() => {
+            traceError(`Server: Stop timed out, forcing termination`);
+        });
         _disposables.forEach((d) => d.dispose());
         _disposables = [];
     }

src/extension.ts

@@ -18,6 +18,7 @@ import { getLSClientTraceLevel } from './common/utilities';
 import { createOutputChannel, onDidChangeConfiguration, registerCommand } from './common/vscodeapi';
 
 let lsClient: LanguageClient | undefined;
+let _isRestarting = false;
 export async function activate(context: vscode.ExtensionContext): Promise<void> {
     // This is required to get server name and module. This should be
     // the first thing that we do in this extension.
@@ -49,28 +50,36 @@ export async function activate(context: vscode.ExtensionContext): Promise<void>
     traceVerbose(`Full Server Info: ${JSON.stringify(serverInfo)}`);
 
     const runServer = async () => {
-        const interpreter = getInterpreterFromSetting(serverId);
-        if (interpreter && interpreter.length > 0) {
-            if (checkVersion(await resolveInterpreter(interpreter))) {
-                traceVerbose(`Using interpreter from ${serverInfo.module}.interpreter: ${interpreter.join(' ')}`);
-                lsClient = await restartServer(serverId, serverName, outputChannel, lsClient);
-            }
+        if (_isRestarting) {
             return;
         }
+        _isRestarting = true;
+        try {
+            const interpreter = getInterpreterFromSetting(serverId);
+            if (interpreter && interpreter.length > 0) {
+                if (checkVersion(await resolveInterpreter(interpreter))) {
+                    traceVerbose(`Using interpreter from ${serverInfo.module}.interpreter: ${interpreter.join(' ')}`);
+                    lsClient = await restartServer(serverId, serverName, outputChannel, lsClient);
+                }
+                return;
+            }
 
-        const interpreterDetails = await getInterpreterDetails();
-        if (interpreterDetails.path) {
-            traceVerbose(`Using interpreter from Python extension: ${interpreterDetails.path.join(' ')}`);
-            lsClient = await restartServer(serverId, serverName, outputChannel, lsClient);
-            return;
-        }
+            const interpreterDetails = await getInterpreterDetails();
+            if (interpreterDetails.path) {
+                traceVerbose(`Using interpreter from Python extension: ${interpreterDetails.path.join(' ')}`);
+                lsClient = await restartServer(serverId, serverName, outputChannel, lsClient);
+                return;
+            }
 
-        traceError(
-            'Python interpreter missing:\r\n' +
-                '[Option 1] Select python interpreter using the ms-python.python.\r\n' +
-                `[Option 2] Set an interpreter using "${serverId}.interpreter" setting.\r\n` +
-                'Please use Python 3.8 or greater.',
-        );
+            traceError(
+                'Python interpreter missing:\r\n' +
+                    '[Option 1] Select python interpreter using the ms-python.python.\r\n' +
+                    `[Option 2] Set an interpreter using "${serverId}.interpreter" setting.\r\n` +
+                    'Please use Python 3.8 or greater.',
+            );
+        } finally {
+            _isRestarting = false;
+        }
     };
 
     context.subscriptions.push(