fix chat messages disappearing when a move is made

Closes #2495
Closes #2781

Author: tom-anders

lib/src/model/chat/chat_controller.dart

@@ -111,14 +111,20 @@ class ChatController extends AsyncNotifier<ChatState> {
       _subscription?.cancel();
     });
 
+    // Do NOT use ref.read() here, since we just need to get the initial messages.
+    // The game/tournament/study controllers do NOT update their `chat` fields when a new
+    // chat message is received, instead the ChatController itselfs listens to this socket event.
+    // This means that with ref.watch(), whenever the game/tournament/study controller updates,
+    // (e.g. when a new move has been made), the `ChatController` would rebuild and we'd lose
+    // any chat messages that have been received since the last build.
     final initialMessages = switch (options) {
-      GameChatOptions(:final id) => (await ref.watch(
+      GameChatOptions(:final id) => (await ref.read(
         gameControllerProvider(id).future,
       )).game.chat?.lines,
-      TournamentChatOptions(:final id) => (await ref.watch(
+      TournamentChatOptions(:final id) => (await ref.read(
         tournamentControllerProvider(id).future,
       )).tournament.chat?.lines,
-      StudyChatOptions(:final id) => (await ref.watch(
+      StudyChatOptions(:final id) => (await ref.read(
         studyControllerProvider(id).future,
       )).study.chat?.lines,
     };

test/view/game/game_screen_test.dart

@@ -23,6 +23,7 @@ import 'package:lichess_mobile/src/model/settings/preferences_storage.dart';
 import 'package:lichess_mobile/src/network/http.dart';
 import 'package:lichess_mobile/src/network/socket.dart';
 import 'package:lichess_mobile/src/styles/lichess_icons.dart';
+import 'package:lichess_mobile/src/view/chat/chat_screen.dart';
 import 'package:lichess_mobile/src/view/game/game_screen.dart';
 import 'package:lichess_mobile/src/view/game/game_screen_providers.dart';
 import 'package:lichess_mobile/src/widgets/bottom_bar.dart';
@@ -963,6 +964,25 @@ void main() {
           () => mockSoundService.play(Sound.confirmation, volume: any(named: 'volume')),
         ).called(1);
       });
+
+      testWidgets('chat messages do not disappear when game state changes', (
+        WidgetTester tester,
+      ) async {
+        await createTestGame(tester, pgn: 'e4 e5');
+        sendServerSocketMessages(testGameSocketUri, [
+          '{"t":"message","d":{"u":"Steven","t":"Hello!"}}',
+        ]);
+        await tester.pump();
+
+        // Play a move to update the GameController's state.
+        // There used to be a bug where this would make chat messages disappear.
+        await playMove(tester, 'g1', 'f3');
+
+        await tester.tap(find.byType(ChatBottomBarButton));
+        await tester.pumpAndSettle(); // wait for chat to open
+
+        expect(find.text('Hello!'), findsOneWidget);
+      });
     });
 
     group('Disabled', () {