Confusing and broken behavior of interactive dismissal on iOS 13

[borut-t]

Step 1: Are you in the right place?

I am 🙄

Step 2: Describe your environment

• Objective C or Swift: Swift
• iOS version: 13.1.2
• Firebase SDK version: 6.9
• FirebaseUI version: 8.2
• CocoaPods Version: 1.8.3

Step 3: Describe the problem:

Steps to reproduce:

Open login UI with only password method.

Observed Results:

When setting shouldHideCancelButton = true on Auth instance, cancel button is hidden but the interactive dismiss is still possible.

Expected Results:

Interactive dismiss should be disabled in this case. It looks like you've only applied interactive dismiss handling on the login method selection screen, but not on a particular screen. I'm not sure about the sdk implementation for this case, but it doesn't work 🤷‍♂

Another interesting thing is if this would work as expected (interactive dismissal disabled), it's really confusing and broken. When the screen is presented, the user cannot cancel the flow if he decides so. I think you should not tie interactive dismissal to the cancel button.
I should be able to:

1. disable interactive dismissal but still be able to cancel the flow or
2. disable cancel and enable interactive dismissal, but interactive dismiss should be handled as cancel event

Relevant Code:

This is a snippet from my code to present email/password login UI:

func presentLoginUI(from vc: UIViewController) {
  let authUi = Auth.auth()
  authUi.tosurl = URL(string: Constants.Legal.tosUrl)
  authUi.delegate = self
  authUi.shouldHideCancelButton = true
  
  let emailAuth = FUIEmailAuth(authAuthUI: authUi, signInMethod: "password", forceSameDevice: true, allowNewEmailAccounts: true, actionCodeSetting: ActionCodeSettings())
  emailAuth.signIn(withPresenting: vc, email: nil)
}

Please fix this asap.

[borut-t]

@morganchen12 can I get some attention here?

[morganchen12]

Yeah, I'll fix this this week. Thanks for reporting 👍

[morganchen12]

You can try the changes here: https://github.com/firebase/FirebaseUI-iOS/pull/792/files

Note that reporting the interactive dismissal cancelation varies based on the presentation method. Currently, if you use the auth picker screen, your presenting view controller's presentation controller will receive dismissal events. If you skip the auth picker view controller, the navigation controller created by FirebaseUI is the one that receives the dismissal events, but since that controller is retained only by the view hierarchy, it's difficult to capture the interactive dismissal event.

I think the best way to resolve this is to expose the created navigation controller in the auth provider sign in method (via return value). This gives users the freedom to do whatever they want to the returned controller, but it's also a breaking API change, so it will not be in the next release.

We can look at adding the new method signature earlier and deprecating the old method.

[borut-t]

@morganchen12 I can confirm your solution works as expected. The idea around the navigation controller exposal is great, but not necessary for this to work.
When can I expect this to be merged and released?

[morganchen12]

I'll release it today or tomorrow.

[morganchen12]

The fix has been released.

[borut-t]

Thanks @morganchen12 🙌