fix: improve promotional offer error handling and logging

- Add detailed error logging for invalid nonce and signature formats
- Throw explicit error when promotional offer validation fails
- Change purchaseOptions to throw errors instead of silently ignoring invalid offers
- Add debug logging to track promotional offer creation

This fix helps developers identify issues with promotional offer signatures
and prevents silent failures when offers are invalid.

Fixes promotional offer "Unable to Purchase" errors by providing clear
error messages when nonce is not a valid UUID or signature is not base64 encoded.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: hyochan

Sources/Helpers/StoreKitTypesBridge.swift

@@ -167,15 +167,22 @@ enum StoreKitTypesBridge {
         return nil
     }
 
-    static func purchaseOptions(from props: RequestPurchaseIosProps) -> Set<StoreKit.Product.PurchaseOption> {
+    static func purchaseOptions(from props: RequestPurchaseIosProps) throws -> Set<StoreKit.Product.PurchaseOption> {
         var options: Set<StoreKit.Product.PurchaseOption> = []
         if let quantity = props.quantity, quantity > 1 {
             options.insert(.quantity(quantity))
         }
         if let token = props.appAccountToken, let uuid = UUID(uuidString: token) {
             options.insert(.appAccountToken(uuid))
         }
-        if let offerInput = props.withOffer, let option = promotionalOffer(from: offerInput) {
+        if let offerInput = props.withOffer {
+            guard let option = promotionalOffer(from: offerInput) else {
+                throw PurchaseError.make(
+                    code: .developerError,
+                    productId: props.sku,
+                    message: "Invalid promotional offer: nonce must be valid UUID and signature must be base64 encoded"
+                )
+            }
             options.insert(option)
         }
         return options
@@ -278,11 +285,19 @@ private extension StoreKitTypesBridge {
     }
 
     static func promotionalOffer(from offer: DiscountOfferInputIOS) -> StoreKit.Product.PurchaseOption? {
-        guard let nonce = UUID(uuidString: offer.nonce),
-              let signature = Data(base64Encoded: offer.signature) else {
+        guard let nonce = UUID(uuidString: offer.nonce) else {
+            OpenIapLog.error("❌ Invalid nonce format: \(offer.nonce)")
+            return nil
+        }
+
+        guard let signature = Data(base64Encoded: offer.signature) else {
+            OpenIapLog.error("❌ Invalid signature format (must be base64): \(offer.signature)")
             return nil
         }
+
         let timestamp = Int(offer.timestamp)
+        OpenIapLog.debug("✅ Creating promotional offer - ID: \(offer.identifier), KeyID: \(offer.keyIdentifier), Timestamp: \(timestamp)")
+
         return .promotionalOffer(
             offerID: offer.identifier,
             keyID: offer.keyIdentifier,

Sources/OpenIapModule.swift

@@ -170,7 +170,7 @@ public final class OpenIapModule: NSObject, OpenIapModuleProtocol {
         let iosProps = try resolveIosPurchaseProps(from: params)
         let sku = iosProps.sku
         let product = try await storeProduct(for: sku)
-        let options = StoreKitTypesBridge.purchaseOptions(from: iosProps)
+        let options = try StoreKitTypesBridge.purchaseOptions(from: iosProps)
 
         let result: StoreKit.Product.PurchaseResult
         #if canImport(UIKit)

openiap-versions.json

@@ -1,4 +1,4 @@
 {
-  "apple": "1.2.11",
+  "apple": "1.2.12",
   "gql": "1.0.12"
 }