fix(player): 修复切换频道时复用已释放的视频控制器

test/playback/playback_session_test.dart

@@ -123,6 +123,38 @@ void main() {
     await session.close();
   });
 
+  test(
+    'should_detach_retiring_player_before_disposal_finishes',
+    () async {
+      final disposeStarted = Completer<void>();
+      final disposeGate = Completer<void>();
+      final factory = FakeFactory(
+        firstDisposeStarted: disposeStarted,
+        firstDisposeGate: disposeGate,
+      );
+      final session = PlaybackSession(
+        episodes: episodes,
+        factory: factory.create,
+        canPlay: (episode) => episode.isFree,
+      );
+      await session.select(0);
+      final retiring = factory.created.single;
+
+      final switching = session.select(1);
+      await disposeStarted.future;
+
+      expect(retiring.disposed, isFalse);
+      expect(session.active, isNull);
+      expect(session.preparedPlayerAt(0), isNull);
+
+      disposeGate.complete();
+      await switching;
+      expect(retiring.disposed, isTrue);
+      expect(session.active, isA<FakePlayer>());
+      await session.close();
+    },
+  );
+
   test('should_keep_user_pause_when_reselecting_the_same_episode', () async {
     final factory = FakeFactory();
     final session = PlaybackSession(
@@ -164,8 +196,14 @@ void main() {
 }
 
 class FakeFactory {
-  FakeFactory({this.holdFirstInitialize = false});
+  FakeFactory({
+    this.holdFirstInitialize = false,
+    this.firstDisposeStarted,
+    this.firstDisposeGate,
+  });
   final bool holdFirstInitialize;
+  final Completer<void>? firstDisposeStarted;
+  final Completer<void>? firstDisposeGate;
   final List<FakePlayer> created = [];
   final Completer<void> firstCreated = Completer<void>();
   int live = 0;
@@ -176,6 +214,8 @@ class FakeFactory {
     if (live > peakLive) peakLive = live;
     final player = FakePlayer(
       holdInitialize: holdFirstInitialize && created.isEmpty,
+      disposeStarted: created.isEmpty ? firstDisposeStarted : null,
+      disposeGate: created.isEmpty ? firstDisposeGate : null,
       onDispose: () => live--,
     );
     created.add(player);
@@ -185,9 +225,16 @@ class FakeFactory {
 }
 
 class FakePlayer implements PlayerPort {
-  FakePlayer({required this.holdInitialize, required this.onDispose});
+  FakePlayer({
+    required this.holdInitialize,
+    required this.onDispose,
+    this.disposeStarted,
+    this.disposeGate,
+  });
   final bool holdInitialize;
   final void Function() onDispose;
+  final Completer<void>? disposeStarted;
+  final Completer<void>? disposeGate;
   final Completer<void> _initializeGate = Completer<void>();
   bool initialized = false;
   bool disposed = false;
@@ -211,6 +258,10 @@ class FakePlayer implements PlayerPort {
   @override
   Future<void> dispose() async {
     if (disposed) return;
+    if (disposeStarted != null && !disposeStarted!.isCompleted) {
+      disposeStarted!.complete();
+    }
+    await disposeGate?.future;
     disposed = true;
     onDispose();
   }