[expo] iOS native Google sign-in fails with "Unable to open Safari." — getPresentingViewController picks an arbitrary scene and window

[Fastdrecad]

Package

@clerk/expo@3.6.5 (useSignInWithGoogle, iOS). The same code is present verbatim in
@clerk/expo-google-signin@1.0.1, so upgrading does not resolve it.

What happens

On a release iOS build, tapping "Continue with Google" never reaches Google. The promise
rejects with one of:

• Unable to open Safari.
• The authorization attempt failed for an unknown reason
• No presenting view controller available

Retrying reproduces it every time within the same session. Sign in with Apple on the same
build is unaffected.

Cause

ios/ClerkGoogleSignInModule.swift resolves the presenting controller like this:

private func getPresentingViewController() -> UIViewController? {
  guard let scene = UIApplication.shared.connectedScenes.first as? UIWindowScene,
        let window = scene.windows.first,
        let rootVC = window.rootViewController else {
    return nil
  }
  ...
}

connectedScenes is a Set and UIWindowScene.windows is unordered, so .first returns an
arbitrary element in both cases — neither checks activationState nor isKeyWindow. An app
with more than one window (splash, keyboard, an overlay from another module) can therefore
hand GIDSignIn a controller that is not in the visible hierarchy.

That produces the two observed outcomes:

• resolution returns nil → the module's own "No presenting view controller available"
• resolution returns an off-screen window → GIDSignIn cannot present its authorization
  session and AppAuth reports OIDErrorCodeSafariOpenError, surfaced through
  handleSignInResult as error.localizedDescription → "Unable to open Safari."

Suggested fix

private func getPresentingViewController() -> UIViewController? {
  let scenes = UIApplication.shared.connectedScenes.compactMap { $0 as? UIWindowScene }
  let scene = scenes.first { $0.activationState == .foregroundActive }
    ?? scenes.first { $0.activationState == .foregroundInactive }
    ?? scenes.first

  guard let window = scene?.windows.first(where: { $0.isKeyWindow })
          ?? scene?.windows.first(where: { !$0.isHidden && $0.rootViewController != nil }),
        let rootVC = window.rootViewController else {
    return nil
  }

  var topVC = rootVC
  while let presentedVC = topVC.presentedViewController, !presentedVC.isBeingDismissed {
    topVC = presentedVC
  }
  return topVC
}

The isBeingDismissed guard covers a related case: a controller mid-dismissal is still
reachable through presentedViewController but can no longer present.

Environment

• Expo SDK 55, React Native 0.83.2, Hermes, Fabric
• iOS 26.5 / 26.6, physical devices and simulator
• GoogleSignIn ~> 9.0 as declared by ClerkGoogleSignIn.podspec

[wobsoriano]

Thanks for reporting! Fix here #9505