fix(debug): debug-brk option does not work for iOS Simulator (#3340)

The `debug-brk` option was broken in a previous commit as we were trying to connect to the backend port (18181). The problem is that connecting to it makes the runtime thinks debugger is attached and it continues to next statements.
Instead of connecting to the port, check if it is in LISTEN state.

Author: rosen-vladimirov

lib/common

@@ -32,7 +32,8 @@ export class IOSDebugService extends DebugServiceBase implements IPlatformDebugS
 		private $iOSNotification: IiOSNotification,
 		private $iOSSocketRequestExecutor: IiOSSocketRequestExecutor,
 		private $processService: IProcessService,
-		private $socketProxyFactory: ISocketProxyFactory) {
+		private $socketProxyFactory: ISocketProxyFactory,
+		private $net: INet) {
 		super(device, $devicesService);
 		this.$processService.attachToProcessExitSignals(this, this.debugStop);
 		this.$socketProxyFactory.on(CONNECTION_ERROR_EVENT_NAME, (e: Error) => this.emit(CONNECTION_ERROR_EVENT_NAME, e));
@@ -125,29 +126,28 @@ export class IOSDebugService extends DebugServiceBase implements IPlatformDebugS
 		const lineStream = byline(child_process.stdout);
 		this._childProcess = child_process;
 
-		await new Promise((resolve: () => void, reject) => {
-			lineStream.on('data', (line: NodeBuffer) => {
-				const lineText = line.toString();
-				if (lineText && _.startsWith(lineText, debugData.applicationIdentifier)) {
-					const pid = getPidFromiOSSimulatorLogs(debugData.applicationIdentifier, lineText);
-					if (!pid) {
-						this.$logger.trace(`Line ${lineText} does not contain PID of the application ${debugData.applicationIdentifier}.`);
-						return;
-					}
-
-					this._lldbProcess = this.$childProcess.spawn("lldb", ["-p", pid]);
-					if (log4js.levels.TRACE.isGreaterThanOrEqualTo(this.$logger.getLevel())) {
-						this._lldbProcess.stdout.pipe(process.stdout);
-					}
-					this._lldbProcess.stderr.pipe(process.stderr);
-					this._lldbProcess.stdin.write("process continue\n");
-					this.connectToApplicationOnEmulator(debugData.deviceIdentifier).then(resolve, reject);
-				} else {
-					process.stdout.write(line + "\n");
+		lineStream.on('data', (line: NodeBuffer) => {
+			const lineText = line.toString();
+			if (lineText && _.startsWith(lineText, debugData.applicationIdentifier)) {
+				const pid = getPidFromiOSSimulatorLogs(debugData.applicationIdentifier, lineText);
+				if (!pid) {
+					this.$logger.trace(`Line ${lineText} does not contain PID of the application ${debugData.applicationIdentifier}.`);
+					return;
 				}
-			});
+
+				this._lldbProcess = this.$childProcess.spawn("lldb", ["-p", pid]);
+				if (log4js.levels.TRACE.isGreaterThanOrEqualTo(this.$logger.getLevel())) {
+					this._lldbProcess.stdout.pipe(process.stdout);
+				}
+				this._lldbProcess.stderr.pipe(process.stderr);
+				this._lldbProcess.stdin.write("process continue\n");
+			} else {
+				process.stdout.write(line + "\n");
+			}
 		});
 
+		await this.waitForBackendPortToBeOpened(debugData.deviceIdentifier);
+
 		return this.wireDebuggerClient(debugData, debugOptions);
 	}
 
@@ -158,13 +158,13 @@ export class IOSDebugService extends DebugServiceBase implements IPlatformDebugS
 
 		const iOSEmulatorService = <Mobile.IiOSSimulatorService>this.$iOSEmulatorServices;
 		await iOSEmulatorService.postDarwinNotification(attachRequestMessage);
-		await this.connectToApplicationOnEmulator(debugData.deviceIdentifier);
+		await this.waitForBackendPortToBeOpened(debugData.deviceIdentifier);
 		return result;
 	}
 
-	private async connectToApplicationOnEmulator(deviceIdentifier: string): Promise<void> {
-		const socket = await this.$iOSEmulatorServices.connectToPort({ port: inspectorBackendPort });
-		if (!socket) {
+	private async waitForBackendPortToBeOpened(deviceIdentifier: string): Promise<void> {
+		const portListens = await this.$net.waitForPortToListen({ port: inspectorBackendPort, timeout: 10000, interval: 200 });
+		if (!portListens) {
 			const error = <Mobile.IDeviceError>new Error("Unable to connect to application. Ensure application is running on simulator.");
 			error.deviceIdentifier = deviceIdentifier;
 			throw error;

lib/services/ios-debug-service.ts

@@ -17,9 +17,10 @@ class IOSDebugServiceInheritor extends IOSDebugService {
 		$iOSNotification: IiOSNotification,
 		$iOSSocketRequestExecutor: IiOSSocketRequestExecutor,
 		$processService: IProcessService,
-		$socketProxyFactory: ISocketProxyFactory) {
+		$socketProxyFactory: ISocketProxyFactory,
+		$net: INet) {
 		super(<any>{}, $devicesService, $platformService, $iOSEmulatorServices, $childProcess, $hostInfo, $logger, $errors,
-			$npmInstallationManager, $iOSNotification, $iOSSocketRequestExecutor, $processService, $socketProxyFactory);
+			$npmInstallationManager, $iOSNotification, $iOSSocketRequestExecutor, $processService, $socketProxyFactory, $net);
 	}
 
 	public getChromeDebugUrl(debugOptions: IDebugOptions, port: number): string {
@@ -49,7 +50,8 @@ const createTestInjector = (): IInjector => {
 	});
 
 	testInjector.register("net", {
-		getAvailablePortInRange: async (startPort: number, endPort?: number): Promise<number> => 41000
+		getAvailablePortInRange: async (startPort: number, endPort?: number): Promise<number> => 41000,
+		waitForPortToListen: async (opts: { port: number, timeout: number, interval?: number }): Promise<boolean> => true
 	});
 
 	return testInjector;