[camera] Dispose resources correctly on setDescription (#4003)

setDescription for CameraController was not correctly handling resources. It would recreate the _deviceOrientationSubscription each time it was called, which caused the subscription to not be disposed correctly. It also was not disposing of the previous device camera

*List which issues are fixed by this PR. You must list at least one issue.*

Issue seen here: https://github.com/flutter/flutter/issues/126823

packages/camera/camera/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 0.10.5+5
+
+* Fixes bug where old camera resources were not disposed when switching between camera descriptions.
+* Fixes bug where _deviceOrientationSubscription was recreated every time the camera description was
+  changed.
+
 ## 0.10.5+4
 
 * Adds pub topics to package metadata.

packages/camera/camera/lib/src/camera_controller.dart

@@ -265,7 +265,10 @@ class CameraController extends ValueNotifier<CameraValue> {
 
   bool _isDisposed = false;
   StreamSubscription<CameraImageData>? _imageStreamSubscription;
-  FutureOr<bool>? _initCalled;
+  // A Future awaiting an attempt to initialize (e.g. after `initialize` was
+  // just called). If the controller has not been initialized at least once,
+  // this value is null.
+  Future<void>? _initializeFuture;
   StreamSubscription<DeviceOrientationChangedEvent>?
       _deviceOrientationSubscription;
 
@@ -294,11 +297,15 @@ class CameraController extends ValueNotifier<CameraValue> {
         'initialize was called on a disposed CameraController',
       );
     }
+
+    final Completer<void> initializeCompleter = Completer<void>();
+    _initializeFuture = initializeCompleter.future;
+
     try {
       final Completer<CameraInitializedEvent> initializeCompleter =
           Completer<CameraInitializedEvent>();
 
-      _deviceOrientationSubscription = CameraPlatform.instance
+      _deviceOrientationSubscription ??= CameraPlatform.instance
           .onDeviceOrientationChanged()
           .listen((DeviceOrientationChangedEvent event) {
         value = value.copyWith(
@@ -343,9 +350,9 @@ class CameraController extends ValueNotifier<CameraValue> {
       );
     } on PlatformException catch (e) {
       throw CameraException(e.code, e.message);
+    } finally {
+      initializeCompleter.complete();
     }
-
-    _initCalled = true;
   }
 
   /// Prepare the capture session for video recording.
@@ -402,6 +409,11 @@ class CameraController extends ValueNotifier<CameraValue> {
       await CameraPlatform.instance.setDescriptionWhileRecording(description);
       value = value.copyWith(description: description);
     } else {
+      if (_initializeFuture != null) {
+        await _initializeFuture;
+        await CameraPlatform.instance.dispose(_cameraId);
+      }
+
       await _initializeWithDescription(description);
     }
   }
@@ -841,8 +853,8 @@ class CameraController extends ValueNotifier<CameraValue> {
     _unawaited(_deviceOrientationSubscription?.cancel());
     _isDisposed = true;
     super.dispose();
-    if (_initCalled != null) {
-      await _initCalled;
+    if (_initializeFuture != null) {
+      await _initializeFuture;
       await CameraPlatform.instance.dispose(_cameraId);
     }
   }

packages/camera/camera/pubspec.yaml

@@ -4,7 +4,7 @@ description: A Flutter plugin for controlling the camera. Supports previewing
   Dart.
 repository: https://github.com/flutter/packages/tree/main/packages/camera/camera
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.10.5+4
+version: 0.10.5+5
 
 environment:
   sdk: ">=2.19.0 <4.0.0"

packages/camera/camera/test/camera_test.dart

@@ -192,6 +192,42 @@ void main() {
           .called(1);
     });
 
+    test('setDescription waits for initialize before calling dispose',
+        () async {
+      final CameraController cameraController = CameraController(
+        const CameraDescription(
+          name: 'cam',
+          lensDirection: CameraLensDirection.back,
+          sensorOrientation: 90,
+        ),
+        ResolutionPreset.max,
+        imageFormatGroup: ImageFormatGroup.bgra8888,
+      );
+
+      final Completer<void> initializeCompleter = Completer<void>();
+      when(CameraPlatform.instance.initializeCamera(
+        mockInitializeCamera,
+        imageFormatGroup: ImageFormatGroup.bgra8888,
+      )).thenAnswer(
+        (_) => initializeCompleter.future,
+      );
+
+      unawaited(cameraController.initialize());
+
+      final Future<void> setDescriptionFuture = cameraController.setDescription(
+        const CameraDescription(
+            name: 'cam2',
+            lensDirection: CameraLensDirection.front,
+            sensorOrientation: 90),
+      );
+      verifyNever(CameraPlatform.instance.dispose(mockInitializeCamera));
+
+      initializeCompleter.complete();
+
+      await setDescriptionFuture;
+      verify(CameraPlatform.instance.dispose(mockInitializeCamera));
+    });
+
     test('prepareForVideoRecording() calls $CameraPlatform ', () async {
       final CameraController cameraController = CameraController(
           const CameraDescription(