iOS App Store validation fails due to non-public selector “rootView” in flutter_unity_widget.framework (Unity 6000)

[thedrhax14]

Describe the bug
During iOS distribution, App Store Connect validation fails because flutter_unity_widget.framework references the non-public selector rootView.

To Reproduce
Steps to reproduce the behavior:

1. Go to a Flutter project using flutter_unity_widget from experimental/unity_6000.
2. Integrate Unity as Library using Unity 6000.1.17f1 and export with fuw-6000.0.2.unitypackage.
3. Build/archive iOS app in Release mode.
4. Upload archive to App Store Connect / validate for distribution.
5. See error:
   Validation failed The app references non-public selectors in Payload/Runner.app/Frameworks/flutter_unity_widget.framework/flutter_unity_widget: rootView (ID: 1a405613-6868-4a78-a7a9-e8da0ec43b10)

Expected behavior
iOS archive should pass App Store Connect validation and distribution without non-public selector errors.

Screenshots
Not applicable, during distribution/upload process in XCode the error message

Unity:
OS: iOS
Version: Unity 6000.1.17f1

Smartphone:
Device: iPhone
OS: iOS 16
Version: App build created from Flutter project using experimental/unity_6000
Additional context

I patched my fork by replacing iOS plugin usage of appController()?.rootView
After patching, archive upload succeeded on App Store Connect.
Android worked as-is in my case.
I’m still validating long-term stability, but current results look good.
My fork (with patch):
I would appreciate others to test and confirm.

[timbotimbo]

Hmm, I haven't seen this error before even though I've submitted tons of updates before.
Although the last one was around October/November, so maybe Apple got stricter.

Can you share your Xcode and Flutter version? Can't hurt to test with a setup that closely matches yours.

It might take me a couple of days to get round to this.

Update

I've also spotted this old issue #407 where a wrong signing setting for the UnityFramework resulted in a warning about rootView.
This was an email from apple instead of upload validation, but it seems like it was a false positive here.