Fix iOS 26.4+ restore: defer handleRestore to allow pending transactions to arrive (#286)

* Initial plan

* Fix iOS restore: defer handleRestore to allow pending transactions to arrive

On iOS 26.4+, restoreCompletedTransactionsFinished may be called before
all restored transactions are delivered via updatedTransactions. This
caused handleRestore to be called with an empty array.

Fix by deferring the handleRestore delivery using a 500ms timer, giving
pending updatedTransactions callbacks time to process restored
transactions first.

Agent-Logs-Url: https://github.com/libgdx/gdx-pay/sessions/9dc875b1-3666-46a7-a485-0946d118e71b

Co-authored-by: keesvandieren <863966+keesvandieren@users.noreply.github.com>

* Add rationale comment for 500ms timer delay

Agent-Logs-Url: https://github.com/libgdx/gdx-pay/sessions/9dc875b1-3666-46a7-a485-0946d118e71b

Co-authored-by: keesvandieren <863966+keesvandieren@users.noreply.github.com>

* Switch from NSTimer to libGDX Timer for restore deferral

Replaces the iOS-specific NSTimer (which didn't compile) with
com.badlogic.gdx.utils.Timer, matching the approach suggested
in issue #285.

Agent-Logs-Url: https://github.com/libgdx/gdx-pay/sessions/042d60fa-727f-43f6-bef1-8e8002016b3b

Co-authored-by: keesvandieren <863966+keesvandieren@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: keesvandieren <863966+keesvandieren@users.noreply.github.com>

Author: Copilot

gdx-pay-iosrobovm-apple/src/main/java/com/badlogic/gdx/pay/ios/apple/PurchaseManageriOSApple.java

@@ -18,6 +18,7 @@
 
 import com.badlogic.gdx.math.MathUtils;
 import com.badlogic.gdx.pay.*;
+import com.badlogic.gdx.utils.Timer;
 import libcore.io.Base64;
 import org.robovm.apple.foundation.*;
 import org.robovm.apple.storekit.*;
@@ -52,6 +53,7 @@ public class PurchaseManageriOSApple implements PurchaseManager {
     private NSArray<SKProduct> products;
 
     private final List<Transaction> restoredTransactions = new ArrayList<Transaction>();
+    private Timer.Task restoreTimerTask;
 
     @Override
     public String storeName () {
@@ -107,6 +109,9 @@ public boolean installed () {
     @Override
     public void dispose () {
         if (appleObserver != null) {
+            // Cancel any pending restore delivery timer.
+            cancelRestoreTimer();
+
             // Remove and null our apple transaction observer.
 
             SKPaymentQueue defaultQueue = SKPaymentQueue.getDefaultQueue();
@@ -151,6 +156,8 @@ public void purchase (String identifier) {
     public void purchaseRestore () {
         log(LOGTYPELOG, "Restoring purchases...");
 
+        // Cancel any pending restore delivery timer.
+        cancelRestoreTimer();
         // Clear previously restored transactions.
         restoredTransactions.clear();
         // Start the restore flow.
@@ -483,16 +490,27 @@ else if (error.getCode() == SKErrorCode.PaymentCancelled.value()) {
 
         @Override
         public void restoreCompletedTransactionsFinished (SKPaymentQueue queue) {
-            // All products have been restored.
             log(LOGTYPELOG, "All transactions have been restored!");
 
-            observer.handleRestore(restoredTransactions.toArray(new Transaction[restoredTransactions.size()]));
-            restoredTransactions.clear();
+            // On iOS 26.4+, restoreCompletedTransactionsFinished may be called
+            // before all restored transactions are delivered via updatedTransactions.
+            // Defer delivery to allow any pending restored transactions to be processed.
+            // 500ms is chosen to safely exceed the observed ~60ms gap between callbacks.
+            cancelRestoreTimer();
+            restoreTimerTask = Timer.schedule(new Timer.Task() {
+                @Override
+                public void run() {
+                    restoreTimerTask = null;
+                    observer.handleRestore(restoredTransactions.toArray(new Transaction[restoredTransactions.size()]));
+                    restoredTransactions.clear();
+                }
+            }, 0.5f);
         }
 
         @Override
         public void restoreCompletedTransactionsFailed (SKPaymentQueue queue, NSError error) {
             // Restoration failed.
+            cancelRestoreTimer();
 
             // Decide if user cancelled or transaction failed.
             if (error.getCode() == SKErrorCode.PaymentCancelled.value()) {
@@ -505,6 +523,13 @@ public void restoreCompletedTransactionsFailed (SKPaymentQueue queue, NSError er
         }
     }
 
+    private void cancelRestoreTimer() {
+        if (restoreTimerTask != null) {
+            restoreTimerTask.cancel();
+            restoreTimerTask = null;
+        }
+    }
+
     void log (final int type, final String message) {
         log(type, message, null);
     }