Improve empty array handling

Incorrect code was being generated for a JSON attribute whose value is an empty array.

Author: ijoshsmith

json2swift/failable-initializer-translation.swift

@@ -67,9 +67,9 @@ fileprivate extension SwiftPrimitiveValueType {
         case .anything,
              .element,
              .elementArray,
-             .emptyArray,
              .nullable,
              .valueArray:                     return .any
+        case .emptyArray:                     return .emptyArray
         case .number(_, let isFloatingPoint): return isFloatingPoint ? .double : .int
         case .date(_, let format):            return .date(format: format)
         case .url:                            return .url

json2swift/swift-code-generation.swift

@@ -246,6 +246,7 @@ internal extension TransformationFromJSON {
     private static func letStatementForPrimitiveValue(_ attributeName: String, _ propertyName: String, _ type: SwiftPrimitiveValueType) -> LineOfCode {
         switch type {
         case .any:                 return "let \(propertyName) = json[\"\(attributeName)\"] as? Any"
+        case .emptyArray:          return "let \(propertyName) = json[\"\(attributeName)\"] as? [Any?]"
         case .bool, .int, .string: return "let \(propertyName) = json[\"\(attributeName)\"] as? \(type.name)"
         case .double:              return "let \(propertyName) = Double(json: json, key: \"\(attributeName)\")" // Allows an integer to be interpreted as a double.
         case .url:                 return "let \(propertyName) = URL(json: json, key: \"\(attributeName)\")"
@@ -267,16 +268,17 @@ internal extension TransformationFromJSON {
 
     private static func letStatementForArrayOfOptionalPrimitiveValues(_ attributeName: String, _ propertyName: String, _ elementType: SwiftPrimitiveValueType) -> LineOfCode {
         switch elementType {
-        case .any, .bool, .int, .string: return "let \(propertyName) = (json[\"\(attributeName)\"] as? [Any]).map({ $0.toOptionalValueArray() as [\(elementType.name)?] })"
-        case .date(let format):          return "let \(propertyName) = (json[\"\(attributeName)\"] as? [Any]).map({ $0.toOptionalDateArray(withFormat: \"\(format)\") })"
-        case .double:                    return "let \(propertyName) = (json[\"\(attributeName)\"] as? [Any]).map({ $0.toOptionalDoubleArray() })"
-        case .url:                       return "let \(propertyName) = (json[\"\(attributeName)\"] as? [Any]).map({ $0.toOptionalURLArray() })"
+        case .any, .bool, .int, .string, .emptyArray: return "let \(propertyName) = (json[\"\(attributeName)\"] as? [Any]).map({ $0.toOptionalValueArray() as [\(elementType.name)?] })"
+        case .date(let format):                       return "let \(propertyName) = (json[\"\(attributeName)\"] as? [Any]).map({ $0.toOptionalDateArray(withFormat: \"\(format)\") })"
+        case .double:                                 return "let \(propertyName) = (json[\"\(attributeName)\"] as? [Any]).map({ $0.toOptionalDoubleArray() })"
+        case .url:                                    return "let \(propertyName) = (json[\"\(attributeName)\"] as? [Any]).map({ $0.toOptionalURLArray() })"
         }
     }
 
     private static func letStatementForArrayOfRequiredPrimitiveValues(_ attributeName: String, _ propertyName: String, _ elementType: SwiftPrimitiveValueType) -> LineOfCode {
         switch elementType {
         case .any:                 return "let \(propertyName) = json[\"\(attributeName)\"] as? [Any?]" // Any is treated as optional.
+        case .emptyArray:          return "let \(propertyName) = json[\"\(attributeName)\"] as? [[Any?]]"
         case .bool, .int, .string: return "let \(propertyName) = json[\"\(attributeName)\"] as? [\(elementType.name)]"
         case .date(let format):    return "let \(propertyName) = (json[\"\(attributeName)\"] as? [String]).flatMap({ $0.toDateArray(withFormat: \"\(format)\") })"
         case .double:              return "let \(propertyName) = (json[\"\(attributeName)\"] as? [NSNumber]).map({ $0.toDoubleArray() })"
@@ -288,13 +290,14 @@ internal extension TransformationFromJSON {
 fileprivate extension SwiftPrimitiveValueType {
     var name: String {
         switch self {
-        case .any:    return "Any"
-        case .bool:   return "Bool"
-        case .date:   return "Date"
-        case .double: return "Double"
-        case .int:    return "Int"
-        case .string: return "String"
-        case .url:    return "URL"
+        case .any:        return "Any"
+        case .bool:       return "Bool"
+        case .date:       return "Date"
+        case .double:     return "Double"
+        case .emptyArray: return "[Any?]"
+        case .int:        return "Int"
+        case .string:     return "String"
+        case .url:        return "URL"
         }
     }
 }

json2swift/swift-data-model.swift

@@ -55,4 +55,5 @@ enum SwiftPrimitiveValueType {
     case string
     case bool
     case any
+    case emptyArray
 }

unit_tests/swift-code-generation-primitive-array-tests.swift

@@ -32,6 +32,11 @@ class swift_code_generation_primitive_array_tests: XCTestCase {
         XCTAssertEqual(transformation.letStatement, "let p = (json[\"a\"] as? [NSNumber]).map({ $0.toDoubleArray() })")
     }
 
+    func test_array_of_required_emptyArray() {
+        let transformation = TransformationFromJSON.toPrimitiveValueArray(attributeName: "a", propertyName: "p", elementType: .emptyArray, hasOptionalElements: false)
+        XCTAssertEqual(transformation.letStatement, "let p = json[\"a\"] as? [[Any?]]")
+    }
+    
     func test_array_of_required_int() {
         let transformation = TransformationFromJSON.toPrimitiveValueArray(attributeName: "a", propertyName: "p", elementType: .int, hasOptionalElements: false)
         XCTAssertEqual(transformation.letStatement, "let p = json[\"a\"] as? [Int]")
@@ -69,6 +74,11 @@ class swift_code_generation_primitive_array_tests: XCTestCase {
         XCTAssertEqual(transformation.letStatement, "let p = (json[\"a\"] as? [Any]).map({ $0.toOptionalDoubleArray() })")
     }
 
+    func test_array_of_optional_emptyArray() {
+        let transformation = TransformationFromJSON.toPrimitiveValueArray(attributeName: "a", propertyName: "p", elementType: .emptyArray, hasOptionalElements: true)
+        XCTAssertEqual(transformation.letStatement, "let p = (json[\"a\"] as? [Any]).map({ $0.toOptionalValueArray() as [[Any?]?] })")
+    }
+    
     func test_array_of_optional_int() {
         let transformation = TransformationFromJSON.toPrimitiveValueArray(attributeName: "a", propertyName: "p", elementType: .int, hasOptionalElements: true)
         XCTAssertEqual(transformation.letStatement, "let p = (json[\"a\"] as? [Any]).map({ $0.toOptionalValueArray() as [Int?] })")

unit_tests/swift-code-generation-primitive-value-tests.swift

@@ -14,6 +14,11 @@ class swift_code_generation_primitive_value_tests: XCTestCase {
         XCTAssertEqual(transformation.letStatement, "let p = json[\"a\"] as? Any")
     }
 
+    func test_emptyArray() {
+        let transformation = TransformationFromJSON.toPrimitiveValue(attributeName: "a", propertyName: "p", type: .emptyArray)
+        XCTAssertEqual(transformation.letStatement, "let p = json[\"a\"] as? [Any?]")
+    }
+    
     func test_bool() {
         let transformation = TransformationFromJSON.toPrimitiveValue(attributeName: "a", propertyName: "p", type: .bool)
         XCTAssertEqual(transformation.letStatement, "let p = json[\"a\"] as? Bool")