Selecting "camera" causes Terminated due to signal 9

Question

In iOS Swift 3.1 I'm trying to access the camera, the same way I have done successfully in other apps. However, in this one particular app, it always crashes on the self.present(imagePicker, animated: true, completion: nil) line. The message in the console is Message from debugger: Terminated due to signal 9. Does this usually signal a memory related error?

@IBAction func onChooseImageClick(_ sender: AnyObject) {
    if UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.savedPhotosAlbum){

        let imagePicker = UIImagePickerController()
        imagePicker.delegate = self

        //Create the AlertController and add Its action like button in Actionsheet
        let actionSheetControllerForImage: UIAlertController = UIAlertController(title: "Please select", message: "Option to select", preferredStyle: .actionSheet)

        let cancelActionButton: UIAlertAction = UIAlertAction(title: "Cancel", style: .cancel) { action -> Void in
            print("Cancel")
        }
        actionSheetControllerForImage.addAction(cancelActionButton)

        let cameraActionButton: UIAlertAction = UIAlertAction(title: "Camera", style: .default)
        { action -> Void in
            print("Camera")
            if(UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.camera)) {
                imagePicker.sourceType = UIImagePickerControllerSourceType.camera
                let mediaTypes:[String] = [kUTTypeImage as String]
                imagePicker.mediaTypes = mediaTypes
                imagePicker.allowsEditing = false

                self.present(imagePicker, animated: true, completion: nil)
            } else {
                let alertController = UIAlertController(title: "error", message: "Camera not found!", preferredStyle: .alert)

                let OKAction = UIAlertAction(title: "OK", style: .cancel) { action in
                    // ...
                }
                alertController.addAction(OKAction)

                self.present(alertController, animated: true)
            }
        }
        actionSheetControllerForImage.addAction(cameraActionButton)

        let galleryActionButton: UIAlertAction = UIAlertAction(title: "Image Gallery", style: .default)
        { action -> Void in
            imagePicker.sourceType = UIImagePickerControllerSourceType.savedPhotosAlbum;
            imagePicker.allowsEditing = false
            self.present(imagePicker, animated: true, completion: nil)
        }
        actionSheetControllerForImage.popoverPresentationController?.sourceView = self.view
        actionSheetControllerForImage.addAction(galleryActionButton)
   ===> self.present(actionSheetControllerForImage, animated: true, completion: nil)
    }
}

Answer 1

You need a string in your plist file that explains why your app need permission to use the camera. There's a great summary of these strings in the question at iOS 10 - Changes in asking permissions of Camera, microphone and Photo Library causing application to crash, with a list you can copy from in the answer at https://stackoverflow.com/a/40734360/968577

Without the required strings, your app will crash in this manner. However, the console output will explain what the problem is.