fix: end existing clients on new start and properly await stop

src/env.ts

@@ -169,9 +169,6 @@ export class Environment {
   }
 
   get client(): LanguageClient | null {
-    if (!this._client) {
-      window.showWarningMessage("Semgrep Language Server not active");
-    }
     return this._client;
   }
 

src/lsp.ts

@@ -8,13 +8,13 @@
   ExecutableOptions,
   LanguageClient,
   type LanguageClientOptions,
   MessageType,
   type NotificationHandler,
   NotificationHandler0,
   type ServerOptions,
   ShowMessageNotification,
   ShowMessageParams,
   TransportKind,
 } from "vscode-languageclient/node";
 import which from "which";
 import {
@@ -25,7 +25,7 @@
   VERSION_PATH,
 } from "./constants";
 import type { Environment } from "./env";
 import { type LspErrorParams, rulesRefreshed } from "./lspExtensions";
 import { setupLanguageClientTracing, topLevelSpan } from "./utilities/tracing";
 
 const execShell = (cmd: string, args: string[]) =>
@@ -76,7 +76,7 @@
   if (!env.config.cfg.get("ignoreCliVersion") && serverPath) {
     // 'osemgrep --version' fails; not sure how intentional that is.
     const version = await execShell(serverPath, ["show", "version"]);
     const semVersion = new semver.SemVer(version);
     env.semgrepVersion = version;
     await env.reloadConfig();
   }
@@ -220,6 +220,12 @@
   // TODO: Remove when semgrep is no longer experimental on Windows.
   if (process.platform === "win32") process.env.SEMGREP_FORCE_INSTALL = "1";
 
+  if (env.client) {
+    env.logger.log("Language client already running, stopping it...");
+    await env.client.stop();
+    env.client = null;
+  }
+
   // Compute LSP server and client options
   const [serverOptions, clientOptions] = await lspOptions(env);
 
@@ -266,10 +272,7 @@
   if (!client) {
     return;
   }
-  await client.sendRequest("shutdown");
-  env?.logger.log("Exiting");
-  await client.sendNotification("exit");
-  client.stop();
+  await client.stop();
   env?.logger.log("Language client stopped...");
 }