Fix Custom Fields Handling in Storage for both Orders and Products

RELEASE-NOTES.txt

@@ -7,6 +7,7 @@
 
 20.6
 -----
+- [**] Users can experience orders not loading or loading slowly if they have a large number of custom fields. This has been fixed now. [https://github.com/woocommerce/woocommerce-ios/pull/14110]
 - [*] Dashboard: Cards are now displayed in 2 columns on large screen sizes. [https://github.com/woocommerce/woocommerce-ios/pull/13983]
 - [*] Jetpack setup: fixed issue checking site info after activating Jetpack for sites with Jetpack connection package. [https://github.com/woocommerce/woocommerce-ios/pull/13993]
 - [*] Blaze: Campaign status is now updated immediately after being canceled. [https://github.com/woocommerce/woocommerce-ios/pull/13992]

Yosemite/Yosemite/Stores/Order/OrdersUpsertUseCase.swift

@@ -304,11 +304,10 @@ struct OrdersUpsertUseCase {
     /// Updates, inserts, or prunes the provided `storageOrder`'s custom fields using the provided `readOnlyOrder`'s custom fields
     ///
     private func handleOrderCustomFields(_ readOnlyOrder: Networking.Order, _ storageOrder: Storage.Order, _ storage: StorageType) {
+        let storedMetaData = storageOrder.customFields
         // Upsert the `customFields` from the `readOnlyOrder`
         readOnlyOrder.customFields.forEach { readOnlyCustomField in
-            if let existingStorageMetaData = storage.loadOrderMetaData(siteID: readOnlyOrder.siteID,
-                                                                       orderID: storageOrder.orderID,
-                                                                       metadataID: readOnlyCustomField.metadataID) {
+            if let existingStorageMetaData = storedMetaData?.first(where: { $0.metadataID == readOnlyCustomField.metadataID }) {
                 existingStorageMetaData.update(with: readOnlyCustomField)
             } else {
                 let newStorageMetaData = storage.insertNewObject(ofType: Storage.MetaData.self)

Yosemite/Yosemite/Stores/ProductStore.swift

@@ -1162,11 +1162,10 @@ extension ProductStore {
     /// Updates, inserts, or prunes the provided `storageProduct`'s custom fields using the provided `readOnlyProduct`'s custom fields
     ///
     private func handleProductCustomFields(_ readOnlyProduct: Networking.Product, _ storageProduct: Storage.Product, _ storage: StorageType) {
+        let storedMetaData = storageProduct.customFields
         // Upsert the `customFields` from the `readOnlyProduct`
         readOnlyProduct.customFields.forEach { readOnlyCustomField in
-            if let existingStorageMetaData = storage.loadProductMetaData(siteID: readOnlyProduct.siteID,
-                                                                         productID: storageProduct.productID,
-                                                                         metadataID: readOnlyCustomField.metadataID) {
+            if let existingStorageMetaData = storedMetaData?.first(where: { $0.metadataID == readOnlyCustomField.metadataID }) {
                 existingStorageMetaData.update(with: readOnlyCustomField)
             } else {
                 let newStorageMetaData = storage.insertNewObject(ofType: Storage.MetaData.self)

Yosemite/YosemiteTests/Stores/Order/OrdersUpsertUseCaseTests.swift

@@ -2,8 +2,7 @@ import XCTest
 
 import Fakes
 import Storage
-import Networking
-
+@testable import Networking
 @testable import Yosemite
 
 final class OrdersUpsertUseCaseTests: XCTestCase {
@@ -262,6 +261,30 @@ final class OrdersUpsertUseCaseTests: XCTestCase {
         XCTAssertEqual(storageCustomField.toReadOnly(), customField)
     }
 
+    func test_it_handles_large_number_of_custom_fields_for_order_and_product_without_deadlock_in_small_amount_of_time() throws {
+        // Given
+        let customFields = (1...2500).map { MetaData(metadataID: $0, key: "Key\($0)", value: "Value\($0)") }
+        let order = makeOrder().copy(siteID: 3, orderID: 98, customFields: customFields)
+        let product = Product.fake().copy(siteID: 3, productID: 99, customFields: customFields)
+        let backgroundContext = storageManager.writerDerivedStorage
+        let orderUseCase = OrdersUpsertUseCase(storage: backgroundContext)
+        let dispatcher = Dispatcher()
+        let network = MockNetwork()
+        let productStore = ProductStore(dispatcher: dispatcher, storageManager: storageManager, network: network)
+
+        // When
+        DispatchQueue.global(qos: .background).async {
+            orderUseCase.upsert([order])
+            productStore.upsertStoredProducts(readOnlyProducts: [product], in: backgroundContext)
+            backgroundContext.saveIfNeeded()
+        }
+
+        // Then
+        self.waitUntil {
+            self.viewStorage.countObjects(ofType: Storage.MetaData.self) == 5000
+        }
+    }
+
     func test_it_persists_order_gift_card_in_storage() throws {
         // Given
         let giftCard = OrderGiftCard(giftCardID: 2, code: "SU9F-MGB5-KS5V-EZFT", amount: 20)