[demolaf]

• Related to Customizable SwiftUI auth UI: content slots, per-screen state, and theming #1400

Adds public MFAResolutionScreen and MFAManagementScreen, so apps can draw the MFA sign-in and factor management screens themselves while the library keeps sending codes, resolving sign-in, unenrolling, reauthenticating and reporting errors.

Changes

• Each screen owns its state and passes its content a MFAResolutionContentState or MFAManagementContentState: Bindings for input, closures for actions, plus isLoading and a localized errorMessage.
• DefaultMFAResolutionContent and DefaultMFAManagementContent hold the stock markup, and MFAResolutionView and MFAManagementView keep their signatures by rendering them through the screens.
• MFAManagementScreen keeps the reauthentication modifier outside the content, so the reauth sheet still presents for custom content.
• isLoading now also covers the AuthService signing in, and the actions ignore repeated taps.

API Usage

AuthPickerView { authenticatedApp }
  .pickerDestination { screen in
    switch screen {
    case let .mfaResolution(mfaRequired):
      MFAResolutionScreen(mfaRequired: mfaRequired) { state in
        TextField("Code", text: state.totpCode)
        Button("Verify", action: state.resolve)
          .disabled(!state.isValid || state.isLoading)
      }
    case .mfaManagement:
      MFAManagementScreen { DefaultMFAManagementContent(state: $0) }
    default:
      DefaultAuthPickerDestination(screen: screen)
    }
  }

Preview

Default resolution, custom resolution, default management, custom management:

---

Maintainer note: Fixes internal CPRN-521

[gemini-code-assist]

Code Review

This pull request refactors the Multi-Factor Authentication (MFA) management and resolution screens by separating state management from UI layout into reusable screen and content views, such as DefaultMFAManagementContent and DefaultMFAResolutionContent. The review feedback highlights three key areas for improvement: replacing a risky force cast with a conditional cast to prevent runtime crashes, avoiding a SwiftUI anti-pattern by enumerating collections instead of using indices with self as the identifier in ForEach, and ensuring backward compatibility for older iOS versions by explicitly discarding the argument in onChange closures.

[gemini-code-assist]

Using a force cast (as!) can lead to runtime crashes if the underlying type is not what is expected (e.g., during testing or if SDK behavior changes). It is safer to use a conditional cast (as?) combined with the existing if check.

        if factor.factorID == PhoneMultiFactorID, let phoneInfo = factor as? PhoneMultiFactorInfo {
          Text("SMS: \(phoneInfo.phoneNumber)")
            .authFont(.caption)
            .foregroundColor(.secondary)
        } else {

[gemini-code-assist]

Using state.hints.indices with id: \.self in a ForEach is a SwiftUI anti-pattern. If the collection changes, the indices can refer to incorrect elements or cause out-of-bounds crashes. Since MFAHint conforms to Hashable, you can safely enumerate the collection and use the element itself as the identifier.

      ForEach(Array(state.hints.enumerated()), id: \.element) { index, hint in
        hintSelectionButton(hint: hint, index: index)
      }

[gemini-code-assist]

In SwiftUI, .onChange(of:action:) with a 0-argument closure was introduced in iOS 17.0. If this library supports older iOS versions (e.g., iOS 14-16), using this signature will cause compilation errors. To maintain backward compatibility, explicitly accept and discard the closure's argument using _ in.

Suggested change

	.onChange(of: selectedHintIndex) {
	verificationCode = ""
	totpCode = ""
	verificationId = nil
	errorMessage = nil
	}
	.onChange(of: verificationCode) { errorMessage = nil }
	.onChange(of: totpCode) { errorMessage = nil }
	.onChange(of: selectedHintIndex) { _ in
	verificationCode = ""
	totpCode = ""
	verificationId = nil
	errorMessage = nil
	}
	.onChange(of: verificationCode) { _ in errorMessage = nil }
	.onChange(of: totpCode) { _ in errorMessage = nil }