Support Dart 3 Record types (#1314)

Closes #1222

Author: kevmoo

json_serializable/CHANGELOG.md

@@ -1,5 +1,6 @@
-## 6.7.0-dev
+## 6.7.0
 
+- Support `Record` types.
 - Require Dart 3.0
 - Require `analyzer: ^5.12.0`
 

json_serializable/README.md

@@ -152,11 +152,11 @@ Out of the box, `json_serializable` supports many common types in the
 [dart:core](https://api.dart.dev/stable/dart-core/dart-core-library.html)
 library: 
 [`BigInt`], [`bool`], [`DateTime`], [`double`], [`Duration`], [`Enum`], [`int`],
-[`Iterable`], [`List`], [`Map`], [`num`], [`Object`], [`Set`], [`String`],
-[`Uri`]
+[`Iterable`], [`List`], [`Map`], [`num`], [`Object`], [`Record`], [`Set`],
+[`String`], [`Uri`]
 
 The collection types –
-[`Iterable`], [`List`], [`Map`], [`Set`]
+[`Iterable`], [`List`], [`Map`], [`Record`], [`Set`]
 – can contain values of all the above types.
 
 For [`Map`], the key value must be one of
@@ -313,6 +313,7 @@ targets:
 [`Map`]: https://api.dart.dev/stable/dart-core/Map-class.html
 [`num`]: https://api.dart.dev/stable/dart-core/num-class.html
 [`Object`]: https://api.dart.dev/stable/dart-core/Object-class.html
+[`Record`]: https://api.dart.dev/stable/dart-core/Record-class.html
 [`Set`]: https://api.dart.dev/stable/dart-core/Set-class.html
 [`String`]: https://api.dart.dev/stable/dart-core/String-class.html
 [`Uri`]: https://api.dart.dev/stable/dart-core/Uri-class.html

json_serializable/build.yaml

@@ -71,6 +71,7 @@ builders:
       - .type_map.dart
       - .type_num.dart
       - .type_object.dart
+      - .type_record.dart
       - .type_set.dart
       - .type_string.dart
       - .type_uri.dart

json_serializable/lib/src/enum_utils.dart

@@ -52,7 +52,9 @@ Map<FieldElement, Object?>? _enumMap(
   DartType targetType, {
   bool nullWithNoAnnotation = false,
 }) {
-  final annotation = _jsonEnumChecker.firstAnnotationOf(targetType.element!);
+  final targetTypeElement = targetType.element;
+  if (targetTypeElement == null) return null;
+  final annotation = _jsonEnumChecker.firstAnnotationOf(targetTypeElement);
   final jsonEnum = _fromAnnotation(annotation);
 
   final enumFields = iterateEnumFields(targetType);

json_serializable/lib/src/helper_core.dart

@@ -77,8 +77,9 @@ $converterOrKeyInstructions
   } else if (field.type != error.type) {
     message = '$message because of type `${typeToCode(error.type)}`';
   } else {
+    final element = error.type.element?.name;
     todo = '''
-To support the type `${error.type.element!.name}` you can:
+To support the type `${element ?? error.type}` you can:
 $converterOrKeyInstructions''';
   }
 

json_serializable/lib/src/json_key_utils.dart

@@ -64,7 +64,7 @@ KeyConfig _from(FieldElement element, ClassConfig classAnnotation) {
       // literal, which is NOT supported!
       badType = 'Function';
     } else if (!reader.isLiteral) {
-      badType = dartObject.type!.element!.name;
+      badType = dartObject.type!.element?.name;
     }
 
     if (badType != null) {

json_serializable/lib/src/settings.dart

@@ -16,6 +16,7 @@ import 'type_helpers/iterable_helper.dart';
 import 'type_helpers/json_converter_helper.dart';
 import 'type_helpers/json_helper.dart';
 import 'type_helpers/map_helper.dart';
+import 'type_helpers/record_helper.dart';
 import 'type_helpers/uri_helper.dart';
 import 'type_helpers/value_helper.dart';
 
@@ -24,6 +25,7 @@ class Settings {
     IterableHelper(),
     MapHelper(),
     EnumHelper(),
+    RecordHelper(),
     ValueHelper(),
   ];
 

json_serializable/lib/src/type_helpers/record_helper.dart

@@ -0,0 +1,124 @@
+import 'package:analyzer/dart/element/type.dart';
+import 'package:source_helper/source_helper.dart';
+
+import '../type_helper.dart';
+import '../utils.dart';
+
+class RecordHelper extends TypeHelper<TypeHelperContextWithConfig> {
+  const RecordHelper();
+
+  @override
+  Object? deserialize(
+    DartType targetType,
+    String expression,
+    TypeHelperContextWithConfig context,
+    bool defaultProvided,
+  ) {
+    if (targetType is! RecordType) return null;
+
+    final items = <Object>[];
+
+    const paramName = r'$jsonValue';
+
+    var index = 1;
+    for (var field in targetType.positionalFields) {
+      final indexer = escapeDartString('\$$index');
+      items.add(
+        context.deserialize(field.type, '$paramName[$indexer]')!,
+      );
+      index++;
+    }
+    for (var field in targetType.namedFields) {
+      final indexer = escapeDartString(field.name);
+      items.add(
+        '${field.name}:'
+        '${context.deserialize(field.type, '$paramName[$indexer]')!}',
+      );
+    }
+
+    if (items.isEmpty) {
+      return '()';
+    }
+
+    context.addMember(
+      _recordConvertImpl(
+          nullable: targetType.isNullableType, anyMap: context.config.anyMap),
+    );
+
+    final recordLiteral = '(${items.map((e) => '$e,').join()})';
+
+    final helperName = _recordConvertName(
+      nullable: targetType.isNullableType,
+      anyMap: context.config.anyMap,
+    );
+
+    return '''
+$helperName(
+  $expression,
+  ($paramName) => $recordLiteral,
+)''';
+  }
+
+  @override
+  Object? serialize(
+    DartType targetType,
+    String expression,
+    TypeHelperContextWithConfig context,
+  ) {
+    if (targetType is! RecordType) return null;
+
+    final maybeBang = targetType.isNullableType ? '!' : '';
+
+    final items = <Object>[];
+
+    var index = 1;
+    for (var field in targetType.positionalFields) {
+      final indexer = escapeDartString('\$$index');
+      items.add(
+        '$indexer:'
+        '${context.serialize(field.type, '$expression$maybeBang.\$$index')!}',
+      );
+      index++;
+    }
+    for (var field in targetType.namedFields) {
+      final indexer = escapeDartString(field.name);
+      items.add(
+        '$indexer:${context.serialize(
+          field.type,
+          '$expression$maybeBang.${field.name}',
+        )!}',
+      );
+    }
+
+    final mapValue = '{${items.map((e) => '$e,').join()}}';
+
+    return targetType.isNullableType
+        ? ifNullOrElse(
+            expression,
+            'null',
+            mapValue,
+          )
+        : mapValue;
+  }
+}
+
+String _recordConvertName({required bool nullable, required bool anyMap}) =>
+    '_\$recordConvert${anyMap ? 'Any' : ''}${nullable ? 'Nullable' : ''}';
+
+String _recordConvertImpl({required bool nullable, required bool anyMap}) {
+  final name = _recordConvertName(nullable: nullable, anyMap: anyMap);
+
+  var expression =
+      'convert(value as ${anyMap ? 'Map' : 'Map<String, dynamic>'})';
+  if (nullable) {
+    expression = ifNullOrElse('value', 'null', expression);
+  }
+
+  return '''
+\$Rec${nullable ? '?' : ''} $name<\$Rec>(
+  Object? value,
+  \$Rec Function(Map) convert,
+) =>
+  $expression;
+''';
+}

json_serializable/pubspec.yaml

@@ -1,5 +1,5 @@
 name: json_serializable
-version: 6.7.0-dev
+version: 6.7.0
 description: >-
   Automatically generate code for converting to and from JSON by annotating
   Dart classes.

json_serializable/test/kitchen_sink/kitchen_sink.dart

@@ -184,6 +184,8 @@ class KitchenSink implements k.KitchenSink {
     _validatedPropertyNo42 = value;
   }
 
+  k.RecordSample? recordField;
+
   bool operator ==(Object other) => k.sinkEquals(this, other);
 
   static Object? _trickyValueAccessor(Map json, String key) {