[in_app_purchase] Fixes StoreKit 2 date format does not match in_app_purchase_platform_interface

- As per `PurchaseDetails.transactionDate` api documentation, date should be `Milliseconds since epoch` but the migration to StoreKit2 probably mistakenly changed the date format to "yyyy-MM-dd HH:mm:ss". The issue originated in StoreKit2Translators.swift `extension Transaction convertToPigeon` which was using a magic hardcoded formatter dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
- Fixes both `SK2Transaction.purchaseDate` and `SK2Transaction.expirationDate` and ultimately `PurchaseDetails.transactionDate`

Fixes flutter/flutter#175072

Author: absar

packages/in_app_purchase/in_app_purchase_storekit/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.4.10
+
+* Fixes StoreKit 2 date format does not match in_app_purchase_platform_interface PurchaseDetails.transactionDate format. 
+  Fixes both `SK2Transaction.purchaseDate` and `SK2Transaction.expirationDate`.
+
 ## 0.4.9
 
 * Add support for offer codes in StoreKit 2.

packages/in_app_purchase/in_app_purchase_storekit/darwin/in_app_purchase_storekit/Sources/in_app_purchase_storekit/StoreKit2/StoreKit2Messages.g.swift

@@ -507,8 +507,8 @@ struct SK2TransactionMessage: Hashable {
   var id: Int64
   var originalId: Int64
   var productId: String
-  var purchaseDate: String? = nil
-  var expirationDate: String? = nil
+  var purchaseDate: Double? = nil
+  var expirationDate: Double? = nil
   var purchasedQuantity: Int64
   var appAccountToken: String? = nil
   var receiptData: String? = nil
@@ -523,8 +523,8 @@ struct SK2TransactionMessage: Hashable {
     let id = pigeonVar_list[0] as! Int64
     let originalId = pigeonVar_list[1] as! Int64
     let productId = pigeonVar_list[2] as! String
-    let purchaseDate: String? = nilOrValue(pigeonVar_list[3])
-    let expirationDate: String? = nilOrValue(pigeonVar_list[4])
+    let purchaseDate: Double? = nilOrValue(pigeonVar_list[3])
+    let expirationDate: Double? = nilOrValue(pigeonVar_list[4])
     let purchasedQuantity = pigeonVar_list[5] as! Int64
     let appAccountToken: String? = nilOrValue(pigeonVar_list[6])
     let receiptData: String? = nilOrValue(pigeonVar_list[7])

packages/in_app_purchase/in_app_purchase_storekit/darwin/in_app_purchase_storekit/Sources/in_app_purchase_storekit/StoreKit2/StoreKit2Translators.swift

@@ -194,16 +194,12 @@ extension Product.PurchaseResult {
 extension Transaction {
   func convertToPigeon(receipt: String?, status: SK2PurchaseStatusMessage) -> SK2TransactionMessage
   {
-
-    let dateFormatter = DateFormatter()
-    dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
-
     return SK2TransactionMessage(
       id: Int64(id),
       originalId: Int64(originalID),
       productId: productID,
-      purchaseDate: dateFormatter.string(from: purchaseDate),
-      expirationDate: expirationDate.map { dateFormatter.string(from: $0) },
+      purchaseDate: purchaseDate.timeIntervalSince1970,
+      expirationDate: expirationDate.map { $0.timeIntervalSince1970 },
       purchasedQuantity: Int64(purchasedQuantity),
       appAccountToken: appAccountToken?.uuidString,
       receiptData: receipt,

packages/in_app_purchase/in_app_purchase_storekit/lib/src/sk2_pigeon.g.dart

@@ -580,9 +580,9 @@ class SK2TransactionMessage {
 
   String productId;
 
-  String? purchaseDate;
+  double? purchaseDate;
 
-  String? expirationDate;
+  double? expirationDate;
 
   int purchasedQuantity;
 
@@ -624,8 +624,8 @@ class SK2TransactionMessage {
       id: result[0]! as int,
       originalId: result[1]! as int,
       productId: result[2]! as String,
-      purchaseDate: result[3] as String?,
-      expirationDate: result[4] as String?,
+      purchaseDate: result[3] as double?,
+      expirationDate: result[4] as double?,
       purchasedQuantity: result[5]! as int,
       appAccountToken: result[6] as String?,
       receiptData: result[7] as String?,

packages/in_app_purchase/in_app_purchase_storekit/lib/src/store_kit_2_wrappers/sk2_transaction_wrapper.dart

@@ -44,9 +44,13 @@ class SK2Transaction {
 
   /// The date that the App Store charged the user's account for a purchased or
   /// restored product, or for a subscription purchase or renewal after a lapse.
+  ///
+  /// Milliseconds since epoch.
   final String purchaseDate;
 
   /// The date the subscription expires or renews.
+  ///
+  /// Milliseconds since epoch.
   final String? expirationDate;
 
   /// The number of consumable products purchased.
@@ -125,8 +129,12 @@ extension on SK2TransactionMessage {
       id: id.toString(),
       originalId: originalId.toString(),
       productId: productId,
-      purchaseDate: purchaseDate ?? '',
-      expirationDate: expirationDate,
+      purchaseDate: purchaseDate != null
+          ? _secondsToMillisecondsSinceEpochString(purchaseDate!)
+          : '',
+      expirationDate: expirationDate != null
+          ? _secondsToMillisecondsSinceEpochString(expirationDate!)
+          : null,
       appAccountToken: appAccountToken,
       receiptData: receiptData,
       jsonRepresentation: jsonRepresentation,
@@ -154,12 +162,17 @@ extension on SK2TransactionMessage {
         serverVerificationData: receiptData ?? '',
         source: kIAPSource,
       ),
-      transactionDate: purchaseDate,
+      transactionDate: purchaseDate != null
+          ? _secondsToMillisecondsSinceEpochString(purchaseDate!)
+          : null,
       status: purchaseStatus,
       purchaseID: id > 0 ? id.toString() : null,
       appAccountToken: appAccountToken,
     );
   }
+
+  String _secondsToMillisecondsSinceEpochString(double date) =>
+      (date * 1000).round().toString();
 }
 
 /// An observer that listens to all transactions created

packages/in_app_purchase/in_app_purchase_storekit/pigeons/sk2_pigeon.dart

@@ -186,8 +186,8 @@ class SK2TransactionMessage {
   final int id;
   final int originalId;
   final String productId;
-  final String? purchaseDate;
-  final String? expirationDate;
+  final double? purchaseDate;
+  final double? expirationDate;
   final int purchasedQuantity;
   final String? appAccountToken;
   final String? receiptData;

packages/in_app_purchase/in_app_purchase_storekit/pubspec.yaml

@@ -2,7 +2,7 @@ name: in_app_purchase_storekit
 description: An implementation for the iOS and macOS platforms of the Flutter `in_app_purchase` plugin. This uses the StoreKit Framework.
 repository: https://github.com/flutter/packages/tree/main/packages/in_app_purchase/in_app_purchase_storekit
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+in_app_purchase%22
-version: 0.4.9
+version: 0.4.10
 
 environment:
   sdk: ^3.10.0

packages/in_app_purchase/in_app_purchase_storekit/test/fakes/fake_storekit_platform.dart

@@ -392,7 +392,6 @@ class FakeStoreKit2Platform implements InAppPurchase2API {
       id: 123,
       originalId: 321,
       productId: '',
-      purchaseDate: '',
       appAccountToken: '',
       status: SK2PurchaseStatusMessage.restored,
     );
@@ -439,7 +438,8 @@ class FakeStoreKit2Platform implements InAppPurchase2API {
           id: 1,
           originalId: 2,
           productId: id,
-          purchaseDate: 'purchaseDate',
+          purchaseDate: 123123.121,
+          expirationDate: 321321.32,
           appAccountToken: 'appAccountToken',
           receiptData: 'receiptData',
           jsonRepresentation: 'jsonRepresentation',
@@ -488,7 +488,7 @@ class FakeStoreKit2Platform implements InAppPurchase2API {
         id: 123,
         originalId: 123,
         productId: 'product_id',
-        purchaseDate: '12-12',
+        purchaseDate: 123123.121,
         status: SK2PurchaseStatusMessage.purchased,
       ),
     ]);
@@ -501,7 +501,8 @@ class FakeStoreKit2Platform implements InAppPurchase2API {
         id: 123,
         originalId: 123,
         productId: 'product_id',
-        purchaseDate: '12-12',
+        purchaseDate: 123123.121,
+        expirationDate: 321321.32,
         receiptData: 'fake_jws_representation',
         appAccountToken: 'fake_app_account_token',
         status: SK2PurchaseStatusMessage.purchased,
@@ -593,7 +594,7 @@ SK2TransactionMessage createPendingTransaction(String id, {int quantity = 1}) {
     id: 1,
     originalId: 2,
     productId: id,
-    purchaseDate: 'purchaseDate',
+    purchaseDate: 123123.121,
     appAccountToken: 'appAccountToken',
     receiptData: 'receiptData',
     jsonRepresentation: 'jsonRepresentation',

packages/in_app_purchase/in_app_purchase_storekit/test/in_app_purchase_storekit_2_platform_test.dart

@@ -122,6 +122,10 @@ void main() {
         expect(result.first.productID, dummyProductWrapper.id);
         expect(result.first.status, PurchaseStatus.purchased);
         expect(result.first.pendingCompletePurchase, true);
+        expect(
+          result.first.transactionDate,
+          (123123.121 * 1000).round().toString(),
+        );
       },
     );
 
@@ -154,6 +158,10 @@ void main() {
         final List<PurchaseDetails> result = await completer.future;
         expect(result.length, 1);
         expect(result.first.productID, dummyProductWrapper.id);
+        expect(
+          result.first.transactionDate,
+          (123123.121 * 1000).round().toString(),
+        );
       },
     );
 
@@ -783,6 +791,10 @@ void main() {
       expect(transactions, isNotEmpty);
       expect(transactions.first.id, '123');
       expect(transactions.first.productId, 'product_id');
+      expect(
+        transactions.first.expirationDate,
+        (321321.32 * 1000).round().toString(),
+      );
     });
 
     test(