Picker's configuration is not a valid configuration, Swift

Question

I am working on new image picker API provided by Apple in WWDC2020 named as PHPicker. I am getting this error when I select the image form the picker second time. First time the code works perfectly. Second time when I click on the button to open the picker, app crashes with the following error. "Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Picker's configuration is not a valid configuration.'".

 @IBAction func addVideo(_ sender: UIButton) {
        presentPicker(filter: .videos)
  }

 private func presentPicker(filter: PHPickerFilter?) {
        var configuration = PHPickerConfiguration(photoLibrary: .shared())
        
        // Set the filter type according to the user’s selection.
        configuration.filter = filter
        // Set the mode to avoid transcoding, if possible, if your app supports arbitrary image/video encodings.
        configuration.preferredAssetRepresentationMode = .current
        // Set the selection behavior to respect the user’s selection order.
        configuration.selection = .ordered
        // Set the selection limit to enable multiselection.
        configuration.selectionLimit = 1
        // Set the preselected asset identifiers with the identifiers that the app tracks.
        configuration.preselectedAssetIdentifiers = selectedAssetIdentifiers
        
        let picker = PHPickerViewController(configuration: configuration)
        picker.delegate = self
        present(picker, animated: true)
    }


func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
        dismiss(animated: true)
        
        let existingSelection = self.selection
        var newSelection = [String: PHPickerResult]()
        for result in results {
            let identifier = result.assetIdentifier!
            newSelection[identifier] = existingSelection[identifier] ?? result
        }
        
        // Track the selection in case the user deselects it later.
        selection = newSelection
        selectedAssetIdentifiers = results.map(\.assetIdentifier!)
        selectedAssetIdentifierIterator = selectedAssetIdentifiers.makeIterator()
        
        if selection.isEmpty {
            displayEmptyImage()
        } else {
            displayImage()
        }
    }

I am using the same code that is provide by apple on their website. https://developer.apple.com/documentation/photokit/phpickerviewcontroller. I just have changed the selectionLimit to 1 from 0.

Answer 1

Apparently it is documented (just kidding, it's in a header file) that the preselectedAssetIdentifiers property is only valid when selectionLimit is greater than 1, which is the default.

Here's an answer from the Apple developer forum for reference: https://developer.apple.com/forums/thread/705493

Answer 2

There must be a problem with your code. I've copy-pasted your solution and it works correctly on Simulator (iOS 15.0).