[in_app_purchase] add Storefront.countryCode() and AppStore.sync() (flutter#8900)

Fixes flutter/flutter#159631 and fixes flutter/flutter#165659

Adds iap support for accessing store front country code and manual transaction syncing.

## Pre-Review Checklist

Author: LouiseHsu

packages/in_app_purchase/in_app_purchase_storekit/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.3.22
+
+* Adds `sync()` and `countryCode()`.
+
 ## 0.3.21
 
 * Adds Swift Package Manager compatibility.

packages/in_app_purchase/in_app_purchase_storekit/darwin/in_app_purchase_storekit/Sources/in_app_purchase_storekit/StoreKit2/InAppPurchasePlugin+StoreKit2.swift

@@ -6,7 +6,6 @@ import StoreKit
 
 @available(iOS 15.0, macOS 12.0, *)
 extension InAppPurchasePlugin: InAppPurchase2API {
-
   // MARK: - Pigeon Functions
 
   /// Wrapper method around StoreKit2's canMakePayments() method
@@ -146,6 +145,43 @@ extension InAppPurchasePlugin: InAppPurchase2API {
     }
   }
 
+  /// Wrapper method around StoreKit2's countryCode() method
+  /// https://developer.apple.com/documentation/storekit/storefront/countrycode
+  func countryCode(completion: @escaping (Result<String, Error>) -> Void) {
+    Task {
+      guard let currentStorefront = await Storefront.current else {
+        let error = PigeonError(
+          code: "storekit2_failed_to_fetch_country_code",
+          message: "Storekit has failed to fetch the country code.",
+          details: "Storefront.current returned nil.")
+        completion(.failure(error))
+        return
+      }
+      completion(.success(currentStorefront.countryCode))
+      return
+    }
+  }
+
+  /// Wrapper method around StoreKit2's sync() method
+  /// https://developer.apple.com/documentation/storekit/appstore/sync()
+  /// When called, a system prompt will ask users to enter their authentication details
+  func sync(completion: @escaping (Result<Void, Error>) -> Void) {
+    Task {
+      do {
+        try await AppStore.sync()
+        completion(.success(()))
+        return
+      } catch {
+        let pigeonError = PigeonError(
+          code: "storekit2_failed_to_sync_to_app_store",
+          message: "Storekit has failed to sync to the app store.",
+          details: "\(error)")
+        completion(.failure(pigeonError))
+        return
+      }
+    }
+  }
+
   /// This Task listens  to Transation.updates as shown here
   /// https://developer.apple.com/documentation/storekit/transaction/3851206-updates
   /// This function should be called as soon as the app starts to avoid missing any Transactions done outside of the app.

packages/in_app_purchase/in_app_purchase_storekit/darwin/in_app_purchase_storekit/Sources/in_app_purchase_storekit/StoreKit2/sk2_pigeon.g.swift

@@ -1,7 +1,7 @@
 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-// Autogenerated from Pigeon (v22.7.3), do not edit directly.
+// Autogenerated from Pigeon (v25.1.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 
 import Foundation
@@ -18,9 +18,9 @@ import Foundation
 final class PigeonError: Error {
   let code: String
   let message: String?
-  let details: Any?
+  let details: Sendable?
 
-  init(code: String, message: String?, details: Any?) {
+  init(code: String, message: String?, details: Sendable?) {
     self.code = code
     self.message = message
     self.details = details
@@ -521,6 +521,8 @@ protocol InAppPurchase2API {
   func startListeningToTransactions() throws
   func stopListeningToTransactions() throws
   func restorePurchases(completion: @escaping (Result<Void, Error>) -> Void)
+  func countryCode(completion: @escaping (Result<String, Error>) -> Void)
+  func sync(completion: @escaping (Result<Void, Error>) -> Void)
 }
 
 /// Generated setup class from Pigeon to handle messages through the `binaryMessenger`.
@@ -676,6 +678,41 @@ class InAppPurchase2APISetup {
     } else {
       restorePurchasesChannel.setMessageHandler(nil)
     }
+    let countryCodeChannel = FlutterBasicMessageChannel(
+      name:
+        "dev.flutter.pigeon.in_app_purchase_storekit.InAppPurchase2API.countryCode\(channelSuffix)",
+      binaryMessenger: binaryMessenger, codec: codec)
+    if let api = api {
+      countryCodeChannel.setMessageHandler { _, reply in
+        api.countryCode { result in
+          switch result {
+          case .success(let res):
+            reply(wrapResult(res))
+          case .failure(let error):
+            reply(wrapError(error))
+          }
+        }
+      }
+    } else {
+      countryCodeChannel.setMessageHandler(nil)
+    }
+    let syncChannel = FlutterBasicMessageChannel(
+      name: "dev.flutter.pigeon.in_app_purchase_storekit.InAppPurchase2API.sync\(channelSuffix)",
+      binaryMessenger: binaryMessenger, codec: codec)
+    if let api = api {
+      syncChannel.setMessageHandler { _, reply in
+        api.sync { result in
+          switch result {
+          case .success:
+            reply(wrapResult(nil))
+          case .failure(let error):
+            reply(wrapError(error))
+          }
+        }
+      }
+    } else {
+      syncChannel.setMessageHandler(nil)
+    }
   }
 }
 /// Generated protocol from Pigeon that represents Flutter messages that can be called from Swift.
@@ -713,7 +750,7 @@ class InAppPurchase2CallbackAPI: InAppPurchase2CallbackAPIProtocol {
         let details: String? = nilOrValue(listResponse[2])
         completion(.failure(PigeonError(code: code, message: message, details: details)))
       } else {
-        completion(.success(Void()))
+        completion(.success(()))
       }
     }
   }

packages/in_app_purchase/in_app_purchase_storekit/lib/src/in_app_purchase_storekit_platform.dart

@@ -241,6 +241,9 @@ class InAppPurchaseStoreKitPlatform extends InAppPurchasePlatform {
   /// See: https://developer.apple.com/documentation/storekit/skstorefront?language=objc
   @override
   Future<String> countryCode() async {
+    if (_useStoreKit2) {
+      return Storefront().countryCode();
+    }
     return (await _skPaymentQueueWrapper.storefront())?.countryCode ?? '';
   }
 

packages/in_app_purchase/in_app_purchase_storekit/lib/src/in_app_purchase_storekit_platform_addition.dart

@@ -3,16 +3,25 @@
 // found in the LICENSE file.
 
 import 'package:in_app_purchase_platform_interface/in_app_purchase_platform_interface.dart';
-import '../in_app_purchase_storekit.dart';
 
+import '../in_app_purchase_storekit.dart';
+import '../store_kit_2_wrappers.dart';
 import '../store_kit_wrappers.dart';
 
 /// Contains InApp Purchase features that are only available on iOS.
 class InAppPurchaseStoreKitPlatformAddition
     extends InAppPurchasePlatformAddition {
+  /// Synchronizes your app’s transaction information and subscription status
+  /// with information from the App Store.
+  /// Storekit 2 only
+  Future<void> sync() {
+    return AppStore().sync();
+  }
+
   /// Present Code Redemption Sheet.
   ///
   /// Available on devices running iOS 14 and iPadOS 14 and later.
+  /// Available for StoreKit 1 and 2
   Future<void> presentCodeRedemptionSheet() {
     return SKPaymentQueueWrapper().presentCodeRedemptionSheet();
   }