[camera_avfoundation] dealloc camera on dispose (flutter#7211)

When is camera disposed in `disposeCamera` it calls `close` and leaves `_camera` untouched so after another call to `sessionQueueCreateCameraWithName` it calls `close` second time and only here is `_camera` disposed by assigning new value into that variable. Calling `close` 2x may be unexpected and prone to later errors if someone adds here something which expects that it will be called only once. Also having dangling `_camera` after dispose (without creating new one) can have other unintended consequences although maybe benign for now. For example there is `[_motionManager stopAccelerometerUpdates]` which is called only in `dealloc`.

Author: misos1

packages/camera/camera_avfoundation/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.17+3
+
+* Fixes deallocation of camera on dispose.
+
 ## 0.9.17+2
 
 * Fixes stopVideoRecording waiting indefinitely and lag at start of video.

packages/camera/camera_avfoundation/example/ios/RunnerTests/CameraMethodChannelTests.m

@@ -50,4 +50,42 @@ - (void)testCreate_ShouldCallResultOnMainThread {
   XCTAssertNotNil(resultValue);
 }
 
+- (void)testDisposeShouldDeallocCamera {
+  CameraPlugin *camera = [[CameraPlugin alloc] initWithRegistry:nil messenger:nil];
+
+  id avCaptureDeviceInputMock = OCMClassMock([AVCaptureDeviceInput class]);
+  OCMStub([avCaptureDeviceInputMock deviceInputWithDevice:[OCMArg any] error:[OCMArg anyObjectRef]])
+      .andReturn([AVCaptureInput alloc]);
+
+  id avCaptureSessionMock = OCMClassMock([AVCaptureSession class]);
+  OCMStub([avCaptureSessionMock alloc]).andReturn(avCaptureSessionMock);
+  OCMStub([avCaptureSessionMock canSetSessionPreset:[OCMArg any]]).andReturn(YES);
+
+  XCTestExpectation *createExpectation =
+      [self expectationWithDescription:@"create's result block must be called"];
+  [camera createCameraOnSessionQueueWithName:@"acamera"
+                                    settings:[FCPPlatformMediaSettings
+                                                 makeWithResolutionPreset:
+                                                     FCPPlatformResolutionPresetMedium
+                                                          framesPerSecond:nil
+                                                             videoBitrate:nil
+                                                             audioBitrate:nil
+                                                              enableAudio:YES]
+                                  completion:^(NSNumber *_Nullable result,
+                                               FlutterError *_Nullable error) {
+                                    [createExpectation fulfill];
+                                  }];
+  [self waitForExpectationsWithTimeout:30 handler:nil];
+  XCTAssertNotNil(camera.camera);
+
+  XCTestExpectation *disposeExpectation =
+      [self expectationWithDescription:@"dispose's result block must be called"];
+  [camera disposeCamera:0
+             completion:^(FlutterError *_Nullable error) {
+               [disposeExpectation fulfill];
+             }];
+  [self waitForExpectationsWithTimeout:30 handler:nil];
+  XCTAssertNil(camera.camera, @"camera should be deallocated after dispose");
+}
+
 @end

packages/camera/camera_avfoundation/ios/camera_avfoundation/Sources/camera_avfoundation/CameraPlugin.m

@@ -416,6 +416,7 @@ - (void)disposeCamera:(NSInteger)cameraId
   __weak typeof(self) weakSelf = self;
   dispatch_async(self.captureSessionQueue, ^{
     [weakSelf.camera close];
+    weakSelf.camera = nil;
     completion(nil);
   });
 }

packages/camera/camera_avfoundation/pubspec.yaml

@@ -2,7 +2,7 @@ name: camera_avfoundation
 description: iOS implementation of the camera plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/camera/camera_avfoundation
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.9.17+2
+version: 0.9.17+3
 
 environment:
   sdk: ^3.2.3