feat: optional scene life cycle so the app starts when built with the iOS 27 SDK #145

app.config.js

@@ -149,6 +149,8 @@ module.exports = {
           sounds: ['./assets/sounds/involved_notification.wav'],
         },
       ],
+      // Builds with the iOS 27 SDK (Xcode 27) must use the scene life cycle.
+      ...(process.env.IOS_SCENE_LIFECYCLE === '1' ? ['./plugins/ios-scene-lifecycle'] : []),
     ],
     extra: {
       commit: COMMIT,

docs/ios-release.md

@@ -158,6 +158,12 @@ Holder has to accept an updated agreement under Business in App Store Connect.
 
 ## What does not work on iOS yet
 
+- **iPhone Duo (#145).** The release is built with Xcode 26, so iOS shows the
+  app at a reduced size there. A build with Xcode 27 needs the scene life
+  cycle: `IOS_SCENE_LIFECYCLE=1` at prebuild adds it
+  (plugins/ios-scene-lifecycle). With it the app starts on the Duo simulator
+  and fills the outer display; links that start the app and push are not yet
+  run under scenes, and nothing is laid out for the inner display.
 - **Client certificates, partly (#3).** The app imports a .p12 into its own
   keychain (plugins/ios-client-cert) and every request of the app answers the
   server's certificate request with it. Two places can't: the notification

plugins/ios-scene-lifecycle.js

@@ -0,0 +1,111 @@
+// UIScene life cycle for builds with the iOS 27 SDK (Xcode 27).
+//
+// The iOS 27 SDK refuses to launch an app that has not adopted scenes
+// ("UIScene life cycle is required for apps built with this SDK"), and Expo
+// ships a scene delegate only from SDK 57.0.23. Until the app is on such an
+// SDK this plugin adopts scenes itself: it declares the scene manifest and
+// moves the window and React Native's start from the app delegate into a
+// scene delegate. The manifest alone is not enough: UIKit then creates the
+// scene, but a window made with UIWindow(frame:) is never attached to it and
+// the app stays black.
+//
+// After expo/expo#50179. The scene delegate is appended to AppDelegate.swift
+// so the Xcode project needs no new file reference.
+const { withAppDelegate, withInfoPlist } = require('expo/config-plugins');
+
+const MARKER = '// plugins/ios-scene-lifecycle';
+
+const WINDOW_RE = /^[ \t]*window = UIWindow\(frame: UIScreen\.main\.bounds\)\r?\n/m;
+const START_RE = /^[ \t]*factory\.startReactNative\(\r?\n[\s\S]*?launchOptions: launchOptions\)\r?\n/m;
+const WINDOW_PROPERTY = '  var window: UIWindow?\n';
+
+const SCENE_DELEGATE = `
+${MARKER}
+class SceneDelegate: UIResponder, UIWindowSceneDelegate {
+  var window: UIWindow?
+
+  func scene(
+    _ scene: UIScene,
+    willConnectTo session: UISceneSession,
+    options connectionOptions: UIScene.ConnectionOptions
+  ) {
+    guard let windowScene = scene as? UIWindowScene,
+          let appDelegate = UIApplication.shared.delegate as? AppDelegate,
+          let factory = appDelegate.reactNativeFactory else {
+      return
+    }
+    let window = UIWindow(windowScene: windowScene)
+    self.window = window
+    // React Native and Expo modules still look for the app delegate's window.
+    appDelegate.window = window
+    factory.startReactNative(
+      withModuleName: "main",
+      in: window,
+      launchOptions: appDelegate.launchOptions)
+    // With scenes, a link that starts the app arrives here and
+    // application(_:open:options:) is never called.
+    open(connectionOptions.urlContexts)
+    for activity in connectionOptions.userActivities {
+      self.scene(scene, continue: activity)
+    }
+  }
+
+  func scene(_ scene: UIScene, openURLContexts URLContexts: Set<UIOpenURLContext>) {
+    open(URLContexts)
+  }
+
+  func scene(_ scene: UIScene, continue userActivity: NSUserActivity) {
+    _ = UIApplication.shared.delegate?.application?(
+      UIApplication.shared, continue: userActivity, restorationHandler: { _ in })
+  }
+
+  // Through the app delegate, whose override hands the link to Expo's
+  // subscribers and to RCTLinkingManager, once.
+  private func open(_ contexts: Set<UIOpenURLContext>) {
+    for context in contexts {
+      _ = UIApplication.shared.delegate?.application?(UIApplication.shared, open: context.url, options: [:])
+    }
+  }
+}
+`;
+
+function withSceneAppDelegate(config) {
+  return withAppDelegate(config, (cfg) => {
+    let contents = cfg.modResults.contents;
+    if (contents.includes(MARKER)) return cfg;
+    for (const [found, what] of [
+      [WINDOW_RE.test(contents), 'window creation'],
+      [START_RE.test(contents), 'startReactNative call'],
+      [contents.includes(WINDOW_PROPERTY), 'window property'],
+    ]) {
+      if (!found) {
+        throw new Error(`ios-scene-lifecycle: AppDelegate.swift has no ${what}; the Expo template changed`);
+      }
+    }
+    contents = contents
+      .replace(WINDOW_RE, '    // The window and React Native start in SceneDelegate (plugins/ios-scene-lifecycle).\n    self.launchOptions = launchOptions\n')
+      .replace(START_RE, '')
+      .replace(WINDOW_PROPERTY, `${WINDOW_PROPERTY}  var launchOptions: [UIApplication.LaunchOptionsKey: Any]?\n`);
+    cfg.modResults.contents = contents + SCENE_DELEGATE;
+    return cfg;
+  });
+}
+
+function withSceneManifest(config) {
+  return withInfoPlist(config, (cfg) => {
+    cfg.modResults.UIApplicationSceneManifest = {
+      UIApplicationSupportsMultipleScenes: false,
+      UISceneConfigurations: {
+        UIWindowSceneSessionRoleApplication: [
+          {
+            UISceneConfigurationName: 'Default Configuration',
+            UISceneDelegateClassName: '$(PRODUCT_MODULE_NAME).SceneDelegate',
+          },
+        ],
+      },
+    };
+    return cfg;
+  });
+}
+
+module.exports = (config) => withSceneManifest(withSceneAppDelegate(config));