ios: Clear transactions which haven't completed

lib/iap.dart

@@ -3,15 +3,19 @@ import 'dart:io' show Platform;
 
 import 'package:http/http.dart' as http;
 import 'package:in_app_purchase/in_app_purchase.dart';
+import 'package:in_app_purchase/store_kit_wrappers.dart';
 import 'package:meta/meta.dart';
 
 import 'package:gitjournal/app.dart';
+import 'package:gitjournal/error_reporting.dart';
 import 'package:gitjournal/features.dart';
 import 'package:gitjournal/settings.dart';
 import 'package:gitjournal/utils/logger.dart';
 
 class InAppPurchases {
   static Future<void> confirmProPurchaseBoot() async {
+    clearTransactionsIos();
+
     if (Features.alwaysPro) {
       return;
     }
@@ -97,6 +101,31 @@ class InAppPurchases {
     }
     return SubscriptionStatus(false, dtNow);
   }
+
+  static Future<void> clearTransactionsIos() async {
+    if (Platform.isIOS) {
+      final transactions = await SKPaymentQueueWrapper().transactions();
+      for (final transaction in transactions) {
+        try {
+          if (transaction.transactionState ==
+              SKPaymentTransactionStateWrapper.purchased) {
+            continue;
+          }
+          if (transaction.transactionState ==
+              SKPaymentTransactionStateWrapper.restored) {
+            continue;
+          }
+
+          if (transaction.transactionState !=
+              SKPaymentTransactionStateWrapper.purchasing) {
+            await SKPaymentQueueWrapper().finishTransaction(transaction);
+          }
+        } catch (e, stackTrace) {
+          logException(e, stackTrace);
+        }
+      }
+    }
+  }
 }
 
 const base_url = 'https://us-central1-gitjournal-io.cloudfunctions.net';