[ndonkoHenri]

Apps made with flet build ipa and Xcode 27 crash at launch on iOS 27, before Python starts. The crash is in UIKit, while the app's first scene is being created:

UIKitCore  _UIApplicationEvaluateRuntimeIssueForNoSceneLifecycleAdoption_block_invoke
UIKitCore  -[UIApplication workspace:didCreateScene:withTransitionContext:completion:]

UIKit logs the reason:

Application failed to launch: UIScene life cycle is required for apps built with this SDK.

The build itself succeeds, so the failure only shows when the app runs on iOS 27. The iOS 26.5 simulator doesn't show it, and CI builds with Xcode 26.6. The build template doesn't adopt the UIScene lifecycle, while client/ios already does.

Fix

The template now matches client/ios/Runner:

• Info.plist: adds UIApplicationSceneManifest with FlutterSceneDelegate.
• AppDelegate.swift: adopts FlutterImplicitEngineDelegate and registers plugins in didInitializeImplicitFlutterEngine, through engineBridge.pluginRegistry. The flutter_local_notifications registrant callback moves there too. UNUserNotificationCenter.current().delegate stays in didFinishLaunchingWithOptions.

Custom build templates need the same two changes, which the changelog notes.

Testing

Built with flet build ipa on Xcode 27.2 and Flutter 3.47.9, with no manual patching of the generated project. The app included flet-audio and flet-notifications, so the flutter_local_notifications branch of AppDelegate.swift was compiled and used.

Before and after, same app:

Build	iOS 27.2 simulator	iOS 26.5 simulator	iPhone, iOS 27.0.1
Without the fix	Crashes at launch (2 of 2 runs)	Works	Crashes at launch
With the fix	Works, audio plays	Works, audio plays	Works, audio plays

"Without the fix" on the simulators is the generated project with the template's previous AppDelegate.swift restored and the scene manifest removed. The iPhone crash came from an earlier app built the same way with the previous template.

With the fix, in more detail:

Check	iPhone 11 Pro Max, iOS 27.0.1	iOS 18.6 simulator
App launches	Works	Works
Audio plays	Works	Works
File picker	Opens and cancels	Not run
Share sheet	Opens and closes	Not run
Notification banner and tap	Works, tap reaches on_tap	Not run
Custom scheme deep link, app closed	page.route is /cold?id=1	Not run
Custom scheme deep link, app running	on_route_change fires	Not verified, no route change logged
Switching apps and back	Correct lifecycle events	Not run

Older SDKs: a copy of the unfixed app with its recorded SDK version changed to 26.5 with vtool launched and played audio on the iOS 27.2 simulator, with no scene error logged. That fits UIKit's message: the requirement seems to apply to apps built with the iOS 27 SDK, so apps already built with an older Xcode should keep launching. It wasn't a real build from an older Xcode.

Not tested

• iOS 15 to 17, and real devices other than this iPhone.
• A real build from an older Xcode running on iOS 27. Every build here used Xcode 27.
• Universal Links, and tapping a notification while the app is closed.
• flet debug and flet test on a device, which use the same template.
• Other plugins that expect the app delegate to have a window. The file picker and share plugins look up the scene's window themselves, and others weren't checked.

Summary by Sourcery

Adopt the UIScene lifecycle in generated iOS apps and align CI coverage with Xcode 27 and iOS 27.

Bug Fixes:

• Prevent iOS apps built with Xcode 27 from crashing at launch on iOS 27 by adopting the required UIScene lifecycle in generated projects.

CI:

• Run iOS tests on Xcode 27 using an available iOS 27 simulator runtime.

Documentation:

• Document the required AppDelegate.swift and Info.plist updates for custom iOS build templates.

[sourcery-ai]

Hey - I've reviewed your changes and they look great!

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