Inject Shipping Address Element dependencies

Committed-By-Agent: codex
Co-authored-by: codex <noreply@openai.com>

Author: gbirch-stripe

StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Checkout/Checkout.swift

@@ -60,7 +60,7 @@ public final class Checkout: ObservableObject {
     private var currencySelectorElement: CurrencySelectorElement?
 
     /// The ShippingAddressElement for this Checkout instance.
-    private var shippingAddressElement: ShippingAddressElement!
+    private let shippingAddressElement: ShippingAddressElement
 
     // TODO(gbirch) TODO(porter) remove this nonisolatedSession
     //  once MPE is properly MainActor isolated
@@ -131,12 +131,30 @@ public final class Checkout: ObservableObject {
             )
             let loadedSession = apiResponse.makePublicSession()
             self.session = loadedSession
-            self.nonisolatedSession = session // temporary hack
+            self.nonisolatedSession = loadedSession // temporary hack
+
+            let defaultShippingAddress: Session.ShippingAddress?
+            if let shippingDetails = configuration.defaults.shippingDetails,
+               let address = shippingDetails.address {
+                defaultShippingAddress = Session.ShippingAddress(
+                    name: shippingDetails.name,
+                    address: address
+                )
+            } else {
+                defaultShippingAddress = nil
+            }
+
+            self.shippingAddressElement = ShippingAddressElement(
+                configuration: configuration.shippingAddressElement,
+                initialShippingAddress: defaultShippingAddress ?? loadedSession.shippingAddress,
+                allowedCountries: loadedSession.allowedShippingCountries,
+                apiClient: configuration.apiClient,
+                useAutocompleteEndpoints: loadedSession.elementsSession.shouldUseAutocompleteProxyEndpoints
+            )
 
             try await applyDefaults()
 
-            // Load elements
-            self.shippingAddressElement = ShippingAddressElement(checkout: self)
+            // Load remaining elements
             self.paymentElement = try await PaymentElement(checkout: self)
             let sessionSource = CheckoutSessionSource(initialSession: session, sessionPublisher: $session)
             self.expressCheckoutElement = ExpressCheckoutElement(

StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Checkout/Shipping Address Element/ShippingAddressElement.swift

@@ -4,6 +4,8 @@
 //
 //  Created by George Birch on 8/4/26.
 
+@_spi(STP) import StripeCore
+
 /// A shipping address form backed by a Checkout Session.
 @MainActor
 @_spi(STP)
@@ -12,15 +14,21 @@ public final class ShippingAddressElement {
 
     private(set) var addressViewController: AddressViewController!
 
-    init(checkout: Checkout) {
-        let configuration = checkout.configuration.shippingAddressElement.makeAddressViewControllerConfiguration(
-            shippingAddress: checkout.session.shippingAddress,
-            allowedCountries: checkout.session.allowedShippingCountries,
-            apiClient: checkout.apiClient,
-            useAutocompleteEndpoints: checkout.session.elementsSession.shouldUseAutocompleteProxyEndpoints
+    init(
+        configuration: Configuration,
+        initialShippingAddress: Checkout.Session.ShippingAddress?,
+        allowedCountries: [String]?,
+        apiClient: STPAPIClient,
+        useAutocompleteEndpoints: Bool
+    ) {
+        let addressViewControllerConfiguration = configuration.makeAddressViewControllerConfiguration(
+            shippingAddress: initialShippingAddress,
+            allowedCountries: allowedCountries,
+            apiClient: apiClient,
+            useAutocompleteEndpoints: useAutocompleteEndpoints
         )
         addressViewController = AddressViewController(
-            configuration: configuration,
+            configuration: addressViewControllerConfiguration,
             delegate: self
         )
     }