[Reliability] Add failsafe decoding when String is received for stock_quantity

Networking/Networking/Extensions/KeyedDecodingContainer+Woo.swift

@@ -116,6 +116,11 @@ extension KeyedDecodingContainer {
         return nil
     }
 
+    /// Decodes a Decimal for the specified key. Supported Encodings = [Decimal / Int / String]
+    ///
+    /// This method *does NOT throw*. We want this behavior so that if a malformed entity is received, we just skip it, rather
+    /// than breaking the entire parsing chain.
+    ///
     func failsafeDecodeIfPresent(decimalForKey key: KeyedDecodingContainer<K>.Key) -> Decimal? {
         if let decimal = failsafeDecodeIfPresent(Decimal.self, forKey: key) {
             return decimal
@@ -125,6 +130,10 @@ extension KeyedDecodingContainer {
             return Decimal(integerLiteral: integerAsDecimal)
         }
 
+        if let stringAsDecimal = failsafeDecodeIfPresent(String.self, forKey: key) {
+            return Decimal(string: stringAsDecimal)
+        }
+
         return nil
     }
 

Networking/Networking/Model/Product/Product.swift

@@ -425,7 +425,11 @@ public struct Product: Codable, GeneratedCopiable, Equatable, GeneratedFakeable
                                                                 })
         ]) ?? false
 
-        let stockQuantity = try container.decodeIfPresent(Decimal.self, forKey: .stockQuantity)
+        // Even though WooCommerce Core returns Int or null values,
+        // some plugins alter the field value from Int to Decimal or String.
+        // We handle this as an optional Decimal value.
+        let stockQuantity = container.failsafeDecodeIfPresent(decimalForKey: .stockQuantity)
+
         let stockStatusKey = try container.decode(String.self, forKey: .stockStatusKey)
 
         let backordersKey = try container.decode(String.self, forKey: .backordersKey)

Networking/Networking/Model/Product/ProductVariation.swift

@@ -274,7 +274,11 @@ public struct ProductVariation: Codable, GeneratedCopiable, Equatable, Generated
                                                                 })
         ]) ?? false
 
-        let stockQuantity = try container.decodeIfPresent(Decimal.self, forKey: .stockQuantity)
+        // Even though WooCommerce Core returns Int or null values,
+        // some plugins alter the field value from Int to Decimal or String.
+        // We handle this as an optional Decimal value.
+        let stockQuantity = container.failsafeDecodeIfPresent(decimalForKey: .stockQuantity)
+
         let stockStatusKey = try container.decode(String.self, forKey: .stockStatusKey)
         let stockStatus = ProductStockStatus(rawValue: stockStatusKey)
         let backordersKey = try container.decode(String.self, forKey: .backordersKey)

Networking/NetworkingTests/Mapper/ProductMapperTests.swift

@@ -125,6 +125,7 @@ final class ProductMapperTests: XCTestCase {
         XCTAssertEqual(product.downloads.first?.downloadID, "12345")
         XCTAssertEqual(product.backordersAllowed, true)
         XCTAssertEqual(product.onSale, false)
+        XCTAssertNil(product.stockQuantity)
     }
 
     /// Verifies that the `salePrice` field of the Product are parsed correctly when the product is on sale, and the sale price is an empty string

Networking/NetworkingTests/Mapper/ProductVariationMapperTests.swift

@@ -44,6 +44,7 @@ final class ProductVariationMapperTests: XCTestCase {
         XCTAssertEqual(productVariation.weight, "2.5")
         XCTAssertEqual(productVariation.backordersAllowed, true)
         XCTAssertEqual(productVariation.onSale, false)
+        XCTAssertEqual(productVariation.stockQuantity, 16)
     }
 
     /// Test that the fields for variations of a subscription product are properly parsed.

Networking/NetworkingTests/Responses/product-alternative-types.json

@@ -40,7 +40,7 @@
             "tax_status": "taxable",
             "tax_class": "",
             "manage_stock": "parent",
-            "stock_quantity": null,
+            "stock_quantity": "",
             "stock_status": "instock",
             "backorders": "no",
             "backorders_allowed": "1",

Networking/NetworkingTests/Responses/product-variation-alternative-types.json

@@ -27,7 +27,7 @@
             "tax_status": "taxable",
             "tax_class": "",
             "manage_stock": "parent",
-            "stock_quantity": 16,
+            "stock_quantity": "16",
             "stock_status": "instock",
             "backorders": "notify",
             "backorders_allowed": "1",

RELEASE-NOTES.txt

@@ -4,6 +4,7 @@
 -----
 - [*] Orders: Allow alternative types for the `taxID` in `ShippingLineTax` or `sku` in `OrderItem`, as some third-party plugins alter the type in the API. This helps with the order list not loading due to order decoding errors. [https://github.com/woocommerce/woocommerce-ios/pull/9844]
 - [*] Payments: Location permissions request is not shown to TTP users who grant "Allow once" permission on first foregrounding the app any more [https://github.com/woocommerce/woocommerce-ios/pull/9821]
+- [*] Products: Allow alternative types for `stockQuantity` in `Product` and `ProductVariation`, as some third-party plugins alter the type in the API. This helps with the product list not loading due to product decoding errors. [https://github.com/woocommerce/woocommerce-ios/pull/9850]
 - [*] Products: Allow alternative types for the `backordersAllowed` and `onSale` in `Product` and `ProductVariation`, as some third-party plugins alter the types in the API. This helps with the product list not loading due to product decoding errors. [https://github.com/woocommerce/woocommerce-ios/pull/9849]
 - [*] Products: Allow alternative types for the `sku` and `weight` in `ProductVariation`, as some third-party plugins alter the types in the API. This helps with the product variation list not loading due to product variation decoding errors. [https://github.com/woocommerce/woocommerce-ios/pull/9847]
 - [*] Products: Allow alternative types for the `sku` and `weight` in `Product`, the dimensions in `ProductDimensions`, and the `downloadID` in `ProductDownload`, as some third-party plugins alter the types in the API. This helps with the product list not loading due to product decoding errors. [https://github.com/woocommerce/woocommerce-ios/pull/9846]