Harden iOS Maestro E2E harness against driver-startup hangs

Summary:
iOS Maestro E2E jobs intermittently fail with `spawnSync /bin/sh ETIMEDOUT` (status 143) and zero Maestro output: Maestro never connects to the simulator driver, so every retry burns the full 10-minute `execSync` timeout before being SIGTERM'd. This change resolves the simulator UDID up front by name (and fails fast with a clear message if no matching device exists) instead of scraping the booted list after an in-flight boot

Changelog: [Internal]

Differential Revision: D109742688

Author: Abbondanzo

.github/workflow-scripts/maestro-ios.js

@@ -38,30 +38,43 @@ const WORKING_DIRECTORY = args[5];
 
 const MAX_ATTEMPTS = 5;
 
-function launchSimulator(simulatorName) {
-  console.log(`Launching simulator ${simulatorName}`);
+function resolveSimulatorUDID(simulatorName) {
+  console.log(`Resolving UDID for simulator "${simulatorName}"`);
+  // Resolve by name (not from the booted list) so we target a specific device
+  // even before it has finished booting.
+  const command = `xcrun simctl list devices available -j | jq -r '[.devices[][] | select(.name == "${simulatorName}")] | first | .udid'`;
+  const udid = String(childProcess.execSync(command)).trim();
+  if (udid === '' || udid === 'null') {
+    throw new Error(
+      `Could not resolve a UDID for a simulator named "${simulatorName}". ` +
+        'Is the device available on this runner?',
+    );
+  }
+  console.log(`UDID is ${udid}`);
+  return udid;
+}
+
+function launchSimulator(udid) {
+  console.log(`Booting simulator ${udid}`);
   try {
-    childProcess.execSync(`xcrun simctl boot "${simulatorName}"`);
+    childProcess.execSync(`xcrun simctl boot "${udid}"`);
   } catch (error) {
     if (
       !error.message.includes('Unable to boot device in current state: Booted')
     ) {
       throw error;
     }
   }
+  // `simctl boot` returns as soon as boot is *initiated*. Block until the device
+  // is fully booted so install/launch/Maestro don't race a half-booted
+  // simulator, which is the usual cause of Maestro hanging on driver startup.
+  console.log('Waiting for the simulator to finish booting');
+  childProcess.execSync(`xcrun simctl bootstatus "${udid}" -b`);
 }
 
-function installAppOnSimulator(appPath) {
+function installAppOnSimulator(udid, appPath) {
   console.log(`Installing app at path ${appPath}`);
-  childProcess.execSync(`xcrun simctl install booted "${appPath}"`);
-}
-
-function extractSimulatorUDID() {
-  console.log('Retrieving device UDID');
-  const command = `xcrun simctl list devices booted -j | jq -r '[.devices[]] | add | first | .udid'`;
-  const udid = String(childProcess.execSync(command)).trim();
-  console.log(`UDID is ${udid}`);
-  return udid;
+  childProcess.execSync(`xcrun simctl install "${udid}" "${appPath}"`);
 }
 
 function bringSimulatorInForeground() {
@@ -123,9 +136,11 @@ function executeTestsWithRetries(
   const recProcess = startVideoRecording(jsengine, currentAttempt);
   try {
     const timeout = 1000 * 60 * 10; // 10 minutes
-    const command = `$HOME/.maestro/bin/maestro --udid="${udid}" test "${maestroFlow}" --format junit -e APP_ID="${appId}"`;
+    const command = `$HOME/.maestro/bin/maestro --udid="${udid}" test "${maestroFlow}" --format junit --debug-output /tmp/MaestroLogs -e APP_ID="${appId}"`;
     console.log(command);
-    childProcess.execSync(`MAESTRO_DRIVER_STARTUP_TIMEOUT=1500000 ${command}`, {
+    // Keep the driver-startup budget well under the execSync `timeout` so a
+    // stuck driver surfaces a real Maestro error instead of a silent SIGTERM.
+    childProcess.execSync(`MAESTRO_DRIVER_STARTUP_TIMEOUT=180000 ${command}`, {
       stdio: 'inherit',
       timeout,
     });
@@ -163,9 +178,9 @@ async function main() {
   console.info('==============================\n');
 
   const simulatorName = 'iPhone 16 Pro';
-  launchSimulator(simulatorName);
-  installAppOnSimulator(APP_PATH);
-  const udid = extractSimulatorUDID();
+  const udid = resolveSimulatorUDID(simulatorName);
+  launchSimulator(udid);
+  installAppOnSimulator(udid, APP_PATH);
   bringSimulatorInForeground();
   await launchAppOnSimulator(APP_ID, udid, IS_DEBUG);
   executeTestsWithRetries(APP_ID, udid, MAESTRO_FLOW, JS_ENGINE, 1);