fix: end existing clients on new start and properly await stop (#264)

* end existing clients on new start and properly await stop

* remove get client warning so it doesn't warn on startup

---------

Co-authored-by: Katrina Liu <katrina@semgrep.com>

Author: brandonspark

src/env.ts

@@ -167,9 +167,6 @@ export class Environment {
   }
 
   get client(): LanguageClient | null {
-    if (!this._client) {
-      window.showWarningMessage("Semgrep Language Server not active");
-    }
     return this._client;
   }
 

src/lsp.ts

@@ -220,6 +220,12 @@ async function start(env: Environment): Promise<void> {
   // 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 @@ async function stop(env: Environment | null): Promise<void> {
   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...");
 }