fix(ui): preserve desktop platform listeners (#1483)

ui/flutter/lib/app/application/app_platform_controller.dart

@@ -54,6 +54,9 @@ class AppPlatformState {
 enum AppUpdateStatus { idle, checking, upToDate, available, failed }
 
 class AppPlatformController extends AsyncNotifier<AppPlatformState> with WindowListener, TrayListener {
+  @protected
+  bool get isDesktop => Util.isDesktop();
+
   bool _started = false;
   String? _trayLocaleConfig;
   bool _updateInitialized = false;
@@ -74,30 +77,54 @@ class AppPlatformController extends AsyncNotifier<AppPlatformState> with WindowL
 
   @override
   Future<AppPlatformState> build() async {
-    final runtime = ref.watch(appRuntimeControllerProvider).value;
-    if (runtime == null || kIsWeb) {
-      return _snapshot();
-    }
-    if (!Util.isDesktop()) {
-      _scheduleInitialUpdateCheck();
-      return _snapshot();
-    }
-    if (_started) {
-      final localeConfig = runtime.downloaderConfig.extra.locale;
-      if (_trayLocaleConfig != localeConfig) await _initTray();
-      return _snapshot();
-    }
-    await _start();
-    _scheduleInitialUpdateCheck();
+    ref.listen(appRuntimeControllerProvider, (_, next) {
+      unawaited(
+        _handleRuntimeChange(next.value).catchError((Object error, StackTrace stackTrace) {
+          if (ref.mounted) state = AsyncValue.error(error, stackTrace);
+        }),
+      );
+    });
     ref.onDispose(() {
+      if (!_started) return;
+      _started = false;
       windowManager.removeListener(this);
       trayManager.removeListener(this);
       unawaited(HostRpcService.instance.stop());
       unawaited(AppWindowCapabilityHost.instance.stop());
     });
+    final runtime = ref.read(appRuntimeControllerProvider).value;
+    if (runtime == null || kIsWeb) {
+      return _snapshot();
+    }
+    if (!isDesktop) {
+      _scheduleInitialUpdateCheck();
+      return _snapshot();
+    }
+    if (_started) {
+      return _snapshot();
+    }
+    await _start();
+    _scheduleInitialUpdateCheck();
     return _snapshot();
   }
 
+  Future<void> _handleRuntimeChange(AppRuntimeState? runtime) async {
+    if (runtime == null || kIsWeb) return;
+    if (!isDesktop) {
+      _scheduleInitialUpdateCheck();
+      return;
+    }
+    if (!_started) {
+      await _start();
+      _scheduleInitialUpdateCheck();
+      _emit();
+      return;
+    }
+    if (_trayLocaleConfig != runtime.downloaderConfig.extra.locale) {
+      await _initTray();
+    }
+  }
+
   void _scheduleInitialUpdateCheck() {
     if (_updateInitialized) return;
     _updateInitialized = true;

ui/flutter/test/app/application/app_platform_controller_test.dart

@@ -0,0 +1,88 @@
+import 'dart:async';
+
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:gopeed/api/model/downloader_config.dart';
+import 'package:gopeed/app/application/app_platform_controller.dart';
+import 'package:gopeed/app/application/app_runtime_controller.dart';
+import 'package:gopeed/core/common/api_server_state.dart';
+import 'package:gopeed/core/common/start_config.dart';
+import 'package:gopeed/util/updater.dart';
+
+void main() {
+  test('runtime updates do not rebuild the platform controller', () async {
+    final container = ProviderContainer(
+      overrides: [
+        appRuntimeControllerProvider.overrideWith(_TestRuntimeController.new),
+        appPlatformControllerProvider.overrideWith(_TestPlatformController.new),
+      ],
+    );
+    addTearDown(container.dispose);
+    final subscription = container.listen(appPlatformControllerProvider, (_, _) {}, fireImmediately: true);
+    addTearDown(subscription.close);
+
+    await container.read(appPlatformControllerProvider.future);
+    final platformController = container.read(appPlatformControllerProvider.notifier) as _TestPlatformController;
+    final runtimeController = container.read(appRuntimeControllerProvider.notifier) as _TestRuntimeController;
+
+    expect(platformController.buildCount, 1);
+
+    runtimeController.completeRuntime();
+    await container.read(appRuntimeControllerProvider.future);
+    await Future<void>.delayed(Duration.zero);
+    expect(platformController.updateCheckCount, 1);
+
+    final config = DownloaderConfig.fromJson(runtimeController.state.requireValue.downloaderConfig.toJson());
+    config.extra.locale = 'zh';
+    runtimeController.replaceDownloaderConfig(config);
+    await container.pump();
+
+    expect(platformController.buildCount, 1);
+  });
+}
+
+class _TestPlatformController extends AppPlatformController {
+  int buildCount = 0;
+  int updateCheckCount = 0;
+
+  @override
+  bool get isDesktop => false;
+
+  @override
+  Future<AppPlatformState> build() {
+    buildCount++;
+    return super.build();
+  }
+
+  @override
+  Future<VersionInfo?> checkForUpdate() async {
+    updateCheckCount++;
+    return null;
+  }
+}
+
+class _TestRuntimeController extends AppRuntimeController {
+  final _pendingRuntime = Completer<AppRuntimeState>();
+
+  @override
+  Future<AppRuntimeState> build() => _pendingRuntime.future;
+
+  void completeRuntime() {
+    _pendingRuntime.complete(
+      AppRuntimeState(
+        startConfig: StartConfig(),
+        apiServerState: const ApiServerState(
+          enabled: false,
+          mcpEnabled: false,
+          running: false,
+          network: '',
+          address: '',
+          runningPort: 0,
+          pendingApply: false,
+          lastError: '',
+        ),
+        downloaderConfig: DownloaderConfig(),
+      ),
+    );
+  }
+}