Add JsonEnum.valueField for encoding enhanced enum values

example/pubspec.yaml

@@ -24,5 +24,7 @@ dev_dependencies:
   test: ^1.16.0
 
 dependency_overrides:
+  json_annotation:
+    path: ../json_annotation
   json_serializable:
     path: ../json_serializable

json_annotation/CHANGELOG.md

@@ -1,5 +1,8 @@
-## 4.6.1-dev
+## 4.7.0
 
+- Added `JsonEnum.valueField` which allows specifying a field in an 
+  "enhanced enum" to use for serialization instead of specifying each value
+  individually with `JsonValue`.
 - Require Dart SDK 2.17
 
 ## 4.6.0

json_annotation/lib/src/json_enum.dart

@@ -13,6 +13,7 @@ class JsonEnum {
   const JsonEnum({
     this.alwaysCreate = false,
     this.fieldRename = FieldRename.none,
+    this.valueField,
   });
 
   /// If `true`, `_$[enum name]EnumMap` is generated for in library containing
@@ -34,4 +35,11 @@ class JsonEnum {
   /// Note: the value for [JsonValue.value] takes precedence over this option
   /// for entries annotated with [JsonValue].
   final FieldRename fieldRename;
+
+  /// Specifies the field within an "enhanced enum" to use as the value
+  /// to use for serialization.
+  ///
+  /// If an individual `enum` element is annotated with `@JsonValue`
+  /// that value still takes precedence.
+  final String? valueField;
 }

json_annotation/pubspec.yaml

@@ -1,5 +1,5 @@
 name: json_annotation
-version: 4.6.1-dev
+version: 4.7.0
 description: >-
   Classes and helper functions that support JSON code generation via the
   `json_serializable` package.

json_serializable/CHANGELOG.md

@@ -1,3 +1,10 @@
+## 6.4.0
+
+- Add support for `JsonEnum.valueField` which allows specifying a field in an
+  "enhanced enum" to use for serialization instead of specifying each value
+  individually with `JsonValue
+- Require `json_annotation: '>=4.7.0 <4.8.0'`
+
 ## 6.3.2
 
 - Require `analyzer: '>=4.6.0 <6.0.0'`

json_serializable/README.md

@@ -200,14 +200,14 @@ targets:
 [`Enum`]: https://api.dart.dev/stable/dart-core/Enum-class.html
 [`int`]: https://api.dart.dev/stable/dart-core/int-class.html
 [`Iterable`]: https://api.dart.dev/stable/dart-core/Iterable-class.html
-[`JsonConverter`]: https://pub.dev/documentation/json_annotation/4.6.0/json_annotation/JsonConverter-class.html
-[`JsonEnum`]: https://pub.dev/documentation/json_annotation/4.6.0/json_annotation/JsonEnum-class.html
-[`JsonKey.fromJson`]: https://pub.dev/documentation/json_annotation/4.6.0/json_annotation/JsonKey/fromJson.html
-[`JsonKey.toJson`]: https://pub.dev/documentation/json_annotation/4.6.0/json_annotation/JsonKey/toJson.html
-[`JsonKey`]: https://pub.dev/documentation/json_annotation/4.6.0/json_annotation/JsonKey-class.html
-[`JsonLiteral`]: https://pub.dev/documentation/json_annotation/4.6.0/json_annotation/JsonLiteral-class.html
-[`JsonSerializable`]: https://pub.dev/documentation/json_annotation/4.6.0/json_annotation/JsonSerializable-class.html
-[`JsonValue`]: https://pub.dev/documentation/json_annotation/4.6.0/json_annotation/JsonValue-class.html
+[`JsonConverter`]: https://pub.dev/documentation/json_annotation/4.7.0/json_annotation/JsonConverter-class.html
+[`JsonEnum`]: https://pub.dev/documentation/json_annotation/4.7.0/json_annotation/JsonEnum-class.html
+[`JsonKey.fromJson`]: https://pub.dev/documentation/json_annotation/4.7.0/json_annotation/JsonKey/fromJson.html
+[`JsonKey.toJson`]: https://pub.dev/documentation/json_annotation/4.7.0/json_annotation/JsonKey/toJson.html
+[`JsonKey`]: https://pub.dev/documentation/json_annotation/4.7.0/json_annotation/JsonKey-class.html
+[`JsonLiteral`]: https://pub.dev/documentation/json_annotation/4.7.0/json_annotation/JsonLiteral-class.html
+[`JsonSerializable`]: https://pub.dev/documentation/json_annotation/4.7.0/json_annotation/JsonSerializable-class.html
+[`JsonValue`]: https://pub.dev/documentation/json_annotation/4.7.0/json_annotation/JsonValue-class.html
 [`List`]: https://api.dart.dev/stable/dart-core/List-class.html
 [`Map`]: https://api.dart.dev/stable/dart-core/Map-class.html
 [`num`]: https://api.dart.dev/stable/dart-core/num-class.html

json_serializable/lib/src/check_dependencies.dart

@@ -10,7 +10,7 @@ import 'package:pubspec_parse/pubspec_parse.dart';
 
 const _productionDirectories = {'lib', 'bin'};
 const _annotationPkgName = 'json_annotation';
-final requiredJsonAnnotationMinVersion = Version.parse('4.6.0');
+final requiredJsonAnnotationMinVersion = Version.parse('4.7.0');
 
 Future<void> pubspecHasRightVersion(BuildStep buildStep) async {
   final segments = buildStep.inputId.pathSegments;

json_serializable/lib/src/enum_utils.dart

@@ -33,20 +33,50 @@ String? enumValueMapFromType(
 
     dynamic fieldValue;
     if (annotation == null) {
-      fieldValue = encodedFieldName(jsonEnum.fieldRename, fe.name);
+      if (jsonEnum.valueField != null) {
+        // TODO: fieldRename is pointless here!!! At least log a warning!
+
+        final fieldElementType = fe.type.element2 as EnumElement;
+
+        final e = fieldElementType.getField(jsonEnum.valueField!);
+
+        if (e == null || e.isStatic) {
+          throw InvalidGenerationSourceError(
+            '`JsonEnum.valueField` was set to "${jsonEnum.valueField}", but '
+            'that is not a valid, instance field on '
+            '`${typeToCode(targetType)}`.',
+            element: targetType.element2,
+          );
+        }
+
+        final reader = ConstantReader(fe.computeConstantValue());
+        final valueReader = reader.read(jsonEnum.valueField!);
+        if (valueReader.validValueType) {
+          fieldValue = valueReader.literalValue;
+        } else {
+          throw InvalidGenerationSourceError(
+            '`JsonEnum.valueField` was set to "${jsonEnum.valueField}", but '
+            'that field does not have a type of String, int, or null.',
+            element: targetType.element2,
+          );
+        }
+      } else {
+        fieldValue = encodedFieldName(jsonEnum.fieldRename, fe.name);
+      }
     } else {
       final reader = ConstantReader(annotation);
 
       final valueReader = reader.read('value');
 
-      if (valueReader.isString || valueReader.isNull || valueReader.isInt) {
+      if (valueReader.validValueType) {
         fieldValue = valueReader.literalValue;
       } else {
         final targetTypeCode = typeToCode(targetType);
         throw InvalidGenerationSourceError(
-            'The `JsonValue` annotation on `$targetTypeCode.${fe.name}` does '
-            'not have a value of type String, int, or null.',
-            element: fe);
+          'The `JsonValue` annotation on `$targetTypeCode.${fe.name}` does '
+          'not have a value of type String, int, or null.',
+          element: fe,
+        );
       }
     }
 
@@ -74,10 +104,16 @@ JsonEnum _fromAnnotation(DartObject? dartObject) {
   }
   final reader = ConstantReader(dartObject);
   return JsonEnum(
-      alwaysCreate: reader.read('alwaysCreate').literalValue as bool,
-      fieldRename: enumValueForDartObject(
-        reader.read('fieldRename').objectValue,
-        FieldRename.values,
-        (f) => f.toString().split('.')[1],
-      ));
+    alwaysCreate: reader.read('alwaysCreate').literalValue as bool,
+    fieldRename: enumValueForDartObject(
+      reader.read('fieldRename').objectValue,
+      FieldRename.values,
+      (f) => f.toString().split('.')[1],
+    ),
+    valueField: reader.read('valueField').literalValue as String?,
+  );
+}
+
+extension on ConstantReader {
+  bool get validValueType => isString || isNull || isInt;
 }

json_serializable/pubspec.yaml

@@ -1,5 +1,5 @@
 name: json_serializable
-version: 6.3.2
+version: 6.4.0-dev
 description: >-
   Automatically generate code for converting to and from JSON by annotating
   Dart classes.
@@ -16,7 +16,7 @@ dependencies:
 
   # Use a tight version constraint to ensure that a constraint on
   # `json_annotation` properly constrains all features it provides.
-  json_annotation: '>=4.6.0 <4.7.0'
+  json_annotation: '>=4.7.0 <4.8.0'
   meta: ^1.3.0
   path: ^1.8.0
   pub_semver: ^2.0.0
@@ -37,3 +37,7 @@ dev_dependencies:
   test_descriptor: ^2.0.0
   test_process: ^2.0.0
   yaml: ^3.0.0
+
+dependency_overrides:
+  json_annotation:
+    path: ../json_annotation

json_serializable/test/integration/json_enum_example.dart

@@ -25,6 +25,19 @@ enum DayType {
 
 Iterable<String> get dayTypeEnumValues => _$DayTypeEnumMap.values;
 
+@JsonEnum(alwaysCreate: true, valueField: 'value')
+enum MyStatusCode {
+  success(200),
+  @JsonValue(701) // explicit value always takes precedence
+  weird(601);
+
+  const MyStatusCode(this.value);
+
+  final int value;
+}
+
+Iterable<int> get myStatusCodeEnumValues => _$MyStatusCodeEnumMap.values;
+
 @JsonSerializable(
   createToJson: false,
 )

json_serializable/test/json_serializable_test.dart

@@ -29,7 +29,13 @@ Future<void> main() async {
   testAnnotatedElements(
     jsonEnumTestReader,
     const JsonEnumGenerator(),
-    expectedAnnotatedTests: {'UnsupportedClass'},
+    expectedAnnotatedTests: {
+      'EnumValueIssue1147',
+      'EnumValueNotAField',
+      'EnumValueNotSupportType',
+      'EnumValueWeirdField',
+      'UnsupportedClass',
+    },
   );
 }
 

json_serializable/test/src/_json_enum_test_input.dart

@@ -5,6 +5,67 @@
 import 'package:json_annotation/json_annotation.dart';
 import 'package:source_gen_test/annotations.dart';
 
+@ShouldGenerate(r'''
+const _$EnumValueIssue1147EnumMap = {
+  EnumValueIssue1147.success: 200,
+  EnumValueIssue1147.weird: 601,
+};
+''')
+@JsonEnum(alwaysCreate: true, valueField: 'statusCodeNumber')
+enum EnumValueIssue1147 {
+  success(200),
+  @JsonValue(601)
+  weird(701);
+
+  const EnumValueIssue1147(this.statusCodeNumber);
+
+  final int statusCodeNumber;
+}
+
+@ShouldThrow(
+  '`JsonEnum.valueField` was set to "notAField", but that is not a valid, '
+  'instance field on `EnumValueNotAField`.',
+)
+@JsonEnum(alwaysCreate: true, valueField: 'notAField')
+enum EnumValueNotAField {
+  success(200),
+  @JsonValue(601)
+  weird(701);
+
+  const EnumValueNotAField(this.statusCodeNumber);
+
+  final int statusCodeNumber;
+}
+
+@ShouldThrow(
+  '`JsonEnum.valueField` was set to "symbolWeird", but that field does not '
+  'have a type of String, int, or null.',
+)
+@JsonEnum(alwaysCreate: true, valueField: 'symbolWeird')
+enum EnumValueNotSupportType {
+  success(#success),
+  @JsonValue(601)
+  weird(#weird);
+
+  const EnumValueNotSupportType(this.symbolWeird);
+
+  final Symbol symbolWeird;
+}
+
+@ShouldThrow(
+  '`JsonEnum.valueField` was set to "values", but that is not a valid, '
+  'instance field on `EnumValueWeirdField`.',
+)
+@JsonEnum(alwaysCreate: true, valueField: 'values')
+enum EnumValueWeirdField {
+  success(200),
+  weird(701);
+
+  const EnumValueWeirdField(this.something);
+
+  final int something;
+}
+
 @ShouldThrow('`@JsonEnum` can only be used on enum elements.')
 @JsonEnum() // ignore: invalid_annotation_target
 class UnsupportedClass {}