Fixes and testing for merchant-initiated repair flows (#4522)

## Summary
<!-- Simple summary of what was changed. -->

This pull request includes fixes for merchant-initiated repair flows in
Financial Connections. We also now allow testing these flows from the
playground by entering a customer and authorization ID.

## Motivation
<!-- Why are you making this change? If it's for fixing a bug, if
possible, please include a code snippet or example project that
demonstrates the issue. -->

## Testing
<!-- How was the code tested? Be as specific as possible. -->

## Changelog
<!-- Is this a notable change that affects users? If so, add a line to
`CHANGELOG.md` and prefix the line with one of the following:
    - [Added] for new features.
    - [Changed] for changes in existing functionality.
    - [Deprecated] for soon-to-be removed features.
    - [Removed] for now removed features.
    - [Fixed] for any bug fixes.
    - [Security] in case of vulnerabilities.
-->

Example/FinancialConnections Example/FinancialConnections Example/Playground/PlaygroundConfiguration.swift

@@ -371,6 +371,36 @@ final class PlaygroundConfiguration {
             configurationStore[Self.phoneKey] = newValue
         }
     }
+
+    // MARK: - Relink Authorization
+
+    private static let customerIdKey = "customer_id"
+    var customerId: String {
+        get {
+            if let customerId = configurationStore[Self.customerIdKey] as? String {
+                return customerId
+            } else {
+                return ""
+            }
+        }
+        set {
+            configurationStore[Self.customerIdKey] = newValue
+        }
+    }
+
+    private static let relinkAuthorizationKey = "relink_authorization"
+    var relinkAuthorization: String {
+        get {
+            if let relinkAuthorization = configurationStore[Self.relinkAuthorizationKey] as? String {
+                return relinkAuthorization
+            } else {
+                return ""
+            }
+        }
+        set {
+            configurationStore[Self.relinkAuthorizationKey] = newValue
+        }
+    }
 
     // MARK: - Permissions
 

Example/FinancialConnections Example/FinancialConnections Example/Playground/PlaygroundView.swift

@@ -114,6 +114,17 @@ struct PlaygroundView: View {
                                 .accessibility(identifier: "playground-phone")
                         }
                     }
+
+                    Section(header: Text("Relink")) {
+                        TextField("Customer ID (cus_)", text: viewModel.customerId)
+                            .keyboardType(.default)
+                            .autocapitalization(.none)
+                            .accessibility(identifier: "playground-customer-id")
+
+                        TextField("Relink authorization (fcauth_)", text: viewModel.relinkAuthorization)
+                            .keyboardType(.default)
+                            .accessibility(identifier: "playground-relink-authorization")
+                    }
 
                     Section(header: Text("PERMISSIONS")) {
                         Toggle("Balances", isOn: viewModel.balancesPermission)

Example/FinancialConnections Example/FinancialConnections Example/Playground/PlaygroundViewModel.swift

@@ -155,6 +155,30 @@ final class PlaygroundViewModel: ObservableObject {
             }
         )
     }
+
+    var customerId: Binding<String> {
+        Binding(
+            get: {
+                self.playgroundConfiguration.customerId
+            },
+            set: {
+                self.playgroundConfiguration.customerId = $0
+                self.objectWillChange.send()
+            }
+        )
+    }
+
+    var relinkAuthorization: Binding<String> {
+        Binding(
+            get: {
+                self.playgroundConfiguration.relinkAuthorization
+            },
+            set: {
+                self.playgroundConfiguration.relinkAuthorization = $0
+                self.objectWillChange.send()
+            }
+        )
+    }
 
     var balancesPermission: Binding<Bool> {
         Binding(

StripeFinancialConnections/StripeFinancialConnections/Source/Native/NativeFlowController.swift

@@ -179,7 +179,10 @@ extension NativeFlowController {
         //
         // keeping this logic in `pushPane` is helpful because we want to
         // reuse `skipSuccessPane` and `manualEntryMode == .custom` logic
-        clearNavigationStack: Bool = false
+        clearNavigationStack: Bool = false,
+        // Useful for cases where we want to prevent the current pane from being shown again,
+        // but not affect any previous panes.
+        removeCurrent: Bool = false
     ) {
         if pane == .success && dataManager.manifest.skipSuccessPane == true {
             closeAuthFlow(error: nil)
@@ -192,8 +195,11 @@ extension NativeFlowController {
                 nativeFlowController: self,
                 dataManager: dataManager
             )
-            if clearNavigationStack, let paneViewController = paneViewController {
+            if clearNavigationStack, let paneViewController {
                 setNavigationControllerViewControllers([paneViewController], animated: animated)
+            } else if removeCurrent, let paneViewController {
+                let viewControllers = Array(navigationController.viewControllers.dropLast())
+                setNavigationControllerViewControllers(viewControllers + [paneViewController], animated: animated)
             } else {
                 pushViewController(paneViewController, animated: animated)
             }
@@ -829,6 +835,14 @@ extension NativeFlowController: PartnerAuthViewControllerDelegate {
 
         showErrorPane(forError: error, referrerPane: .partnerAuth)
     }
+
+    func partnerAuthViewController(
+        _ viewController: PartnerAuthViewController,
+        didRequestNextPane nextPane: FinancialConnectionsSessionManifest.NextPane
+    ) {
+        dataManager.authSession = nil // clear any lingering auth sessions
+        pushPane(nextPane, animated: true, removeCurrent: true)
+    }
 }
 
 // MARK: - AccountPickerViewControllerDelegate

StripeFinancialConnections/StripeFinancialConnections/Source/Native/PartnerAuth/PartnerAuthViewController.swift

@@ -25,6 +25,10 @@ protocol PartnerAuthViewControllerDelegate: AnyObject {
         _ viewController: PartnerAuthViewController,
         didReceiveError error: Error
     )
+    func partnerAuthViewController(
+        _ viewController: PartnerAuthViewController,
+        didRequestNextPane nextPane: FinancialConnectionsSessionManifest.NextPane
+    )
 }
 
 final class PartnerAuthViewController: SheetViewController {
@@ -157,7 +161,20 @@ final class PartnerAuthViewController: SheetViewController {
                 },
                 didSelectCancel: { [weak self] in
                     guard let self = self else { return }
-                    self.delegate?.partnerAuthViewControllerDidRequestToGoBack(self)
+                    let isModal = panePresentationStyle == .sheet
+
+                    self.dataSource.analyticsClient.log(
+                        eventName: isModal ? "click.prepane.cancel" : "click.prepane.choose_another_bank",
+                        pane: .partnerAuth
+                    )
+
+                    self.dataSource.cancelPendingAuthSessionIfNeeded()
+
+                    if isModal {
+                        self.delegate?.partnerAuthViewControllerDidRequestToGoBack(self)
+                    } else {
+                        self.delegate?.partnerAuthViewController(self, didRequestNextPane: .institutionPicker)
+                    }
                 }
             )
             self.prepaneViews = prepaneViews