Revert "fix: remove TSC_NONPOLLING_WATCHER env variable" (#1316)

This reverts commit 17708d4.

Fixes #1310

We need to do more investigation into the default watch options and
setting them in the `ProjectService` host configuration.

Author: atscott

client/src/client.ts

@@ -403,7 +403,10 @@ function constructArgs(ctx: vscode.ExtensionContext): string[] {
 
 function getServerOptions(ctx: vscode.ExtensionContext, debug: boolean): lsp.NodeModule {
   // Environment variables for server process
-  const prodEnv = {};
+  const prodEnv = {
+    // Force TypeScript to use the non-polling version of the file watchers.
+    TSC_NONPOLLING_WATCHER: true,
+  };
   const devEnv = {
     ...prodEnv,
     NG_DEBUG: true,

integration/lsp/test_utils.ts

@@ -30,6 +30,9 @@ export function createConnection(serverOptions: ServerOptions): MessageConnectio
   }
   const server = fork(SERVER_PATH, argv, {
     cwd: PROJECT_PATH,
+    env: {
+      TSC_NONPOLLING_WATCHER: 'true',
+    },
     // uncomment to debug server process
     // execArgv: ['--inspect-brk=9330']
   });

server/src/server.ts

@@ -59,6 +59,10 @@ function main() {
     session.info('Angular Language Service is running under DEBUG mode');
   }
 
+  if (process.env.TSC_NONPOLLING_WATCHER !== 'true') {
+    session.warn(`Using less efficient polling watcher. Set TSC_NONPOLLING_WATCHER to true.`);
+  }
+
   session.listen();
 }