Support non-JSON object decodable values in getMetadataValue (#4555)

* support non-JSON decodable values in getMetadataValue

* remove method definition claiming to throw

* Update Offering.swift

* test for primitive decodable metadata values without a default

* simplify decoding

Sources/Purchasing/Offering.swift

@@ -310,20 +310,21 @@ extension Offering {
     }
 
     /// - Returns: The `metadata` value associated to `key` for the expected `Decodable` type,
-    /// or `nil` if not found.
-    /// - Throws: Error if the content couldn't be deserialized to the expected type.
+    /// or `nil` if not found or if the content couldn't be deserialized to the expected type.
     /// - Note: This decodes JSON using `JSONDecoder.KeyDecodingStrategy.convertFromSnakeCase`.
     public func getMetadataValue<T: Decodable>(for key: String) -> T? {
-        do {
-            guard let value = self.metadata[key] else { return nil }
-            let data = try JSONSerialization.data(withJSONObject: value)
-
-            return try JSONDecoder.default.decode(
-                T.self,
-                jsonData: data,
-                logErrors: true
-            )
-        } catch {
+        guard let value = self.metadata[key] else { return nil }
+
+        if JSONSerialization.isValidJSONObject(value),
+            let data = try? JSONSerialization.data(withJSONObject: value) {
+            return try? JSONDecoder.default.decode(
+                            T.self,
+                            jsonData: data,
+                            logErrors: true
+                        )
+        } else if let value = value as? T {
+            return value
+        } else {
             return nil
         }
     }

Tests/UnitTests/Purchasing/OfferingsTests.swift

@@ -410,6 +410,18 @@ class OfferingsTests: TestCase {
         let wrongMetadataType = offeringA.getMetadataValue(for: "string", default: 5.5)
         expect(wrongMetadataType) == 5.5
 
+        let intWithoutDefault: Int? = offeringA.getMetadataValue(for: "int")
+        expect(intWithoutDefault) == 5
+
+        let doubleWithoutDefault: Double? = offeringA.getMetadataValue(for: "double")
+        expect(doubleWithoutDefault) == 5.5
+
+        let boolWithoutDefault: Bool? = offeringA.getMetadataValue(for: "boolean")
+        expect(boolWithoutDefault) == true
+
+        let stringWithoutDefault: String? = offeringA.getMetadataValue(for: "string")
+        expect(stringWithoutDefault) == "five"
+
         struct Data: Decodable, Equatable {
             var number: Int
         }