Add JsonConverter(converters) option

json_annotation/lib/src/json_serializable.dart

@@ -6,6 +6,7 @@ import 'package:meta/meta_meta.dart';
 
 import 'allowed_keys_helpers.dart';
 import 'checked_helpers.dart';
+import 'json_converter.dart';
 import 'json_key.dart';
 
 part 'json_serializable.g.dart';
@@ -190,6 +191,40 @@ class JsonSerializable {
   /// `includeIfNull`, that value takes precedent.
   final bool? includeIfNull;
 
+  /// A list of [JsonConverter] to apply to this class.
+  ///
+  /// Writing:
+  ///
+  /// ```dart
+  /// @JsonSerializable(converters: [MyJsonConverter()])
+  /// class Example {...}
+  /// ```
+  ///
+  /// is equivalent to writing:
+  ///
+  /// ```dart
+  /// @JsonSerializable()
+  /// @MyJsonConverter()
+  /// class Example {...}
+  /// ```
+  ///
+  /// The main difference is that this allows reusing a custom
+  /// [JsonSerializable] over multiple classes:
+  ///
+  /// ```dart
+  /// const myCustomAnnotation = JsonSerializable(
+  ///   converters: [MyJsonConverter()],
+  /// );
+  ///
+  /// @myCustomAnnotation
+  /// class Example {...}
+  ///
+  /// @myCustomAnnotation
+  /// class Another {...}
+  /// ```
+  @JsonKey(ignore: true)
+  final List<JsonConverter>? converters;
+
   /// Creates a new [JsonSerializable] instance.
   const JsonSerializable({
     @Deprecated('Has no effect') bool? nullable,
@@ -203,6 +238,7 @@ class JsonSerializable {
     this.fieldRename,
     this.ignoreUnannotated,
     this.includeIfNull,
+    this.converters,
     this.genericArgumentFactories,
   });
 

json_serializable/lib/src/json_serializable_generator.dart

@@ -20,7 +20,7 @@ class JsonSerializableGenerator
     extends GeneratorForAnnotation<JsonSerializable> {
   final Settings _settings;
 
-  JsonSerializable get config => _settings.config;
+  JsonSerializable get config => _settings.config.toJsonSerializable();
 
   JsonSerializableGenerator.fromSettings(this._settings);
 

json_serializable/lib/src/settings.dart

@@ -43,38 +43,19 @@ class Settings {
         GenericFactoryHelper(),
       ].followedBy(_typeHelpers).followedBy(_coreHelpers);
 
-  final JsonSerializable _config;
-
-  // #CHANGE WHEN UPDATING json_annotation
-  ClassConfig get config => ClassConfig(
-        checked: _config.checked ?? ClassConfig.defaults.checked,
-        anyMap: _config.anyMap ?? ClassConfig.defaults.anyMap,
-        constructor: _config.constructor ?? ClassConfig.defaults.constructor,
-        createFactory:
-            _config.createFactory ?? ClassConfig.defaults.createFactory,
-        createToJson: _config.createToJson ?? ClassConfig.defaults.createToJson,
-        ignoreUnannotated:
-            _config.ignoreUnannotated ?? ClassConfig.defaults.ignoreUnannotated,
-        explicitToJson:
-            _config.explicitToJson ?? ClassConfig.defaults.explicitToJson,
-        includeIfNull:
-            _config.includeIfNull ?? ClassConfig.defaults.includeIfNull,
-        genericArgumentFactories: _config.genericArgumentFactories ??
-            ClassConfig.defaults.genericArgumentFactories,
-        fieldRename: _config.fieldRename ?? ClassConfig.defaults.fieldRename,
-        disallowUnrecognizedKeys: _config.disallowUnrecognizedKeys ??
-            ClassConfig.defaults.disallowUnrecognizedKeys,
-      );
+  final ClassConfig config;
 
   /// Creates an instance of [Settings].
   ///
   /// If [typeHelpers] is not provided, the built-in helpers are used:
   /// [BigIntHelper], [DateTimeHelper], [DurationHelper], [JsonHelper], and
   /// [UriHelper].
-  const Settings({
+  Settings({
     JsonSerializable? config,
     List<TypeHelper>? typeHelpers,
-  })  : _config = config ?? ClassConfig.defaults,
+  })  : config = config != null
+            ? ClassConfig.fromJsonSerializable(config)
+            : ClassConfig.defaults,
         _typeHelpers = typeHelpers ?? defaultHelpers;
 
   /// Creates an instance of [Settings].

json_serializable/lib/src/type_helpers/config_types.dart

@@ -2,6 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'package:analyzer/dart/constant/value.dart';
 import 'package:json_annotation/json_annotation.dart';
 
 /// Represents values from [JsonKey] when merged with local configuration.
@@ -38,41 +39,20 @@ class KeyConfig {
 /// configuration.
 ///
 /// Values are all known, so types are non-nullable.
-class ClassConfig implements JsonSerializable {
-  @override
+class ClassConfig {
   final bool anyMap;
-
-  @override
   final bool checked;
-
-  @override
   final String constructor;
-
-  @override
   final bool createFactory;
-
-  @override
   final bool createToJson;
-
-  @override
   final bool disallowUnrecognizedKeys;
-
-  @override
   final bool explicitToJson;
-
-  @override
   final FieldRename fieldRename;
-
-  @override
   final bool genericArgumentFactories;
-
-  @override
   final bool ignoreUnannotated;
-
-  @override
   final bool includeIfNull;
-
   final Map<String, String> ctorParamDefaults;
+  final List<DartObject> converters;
 
   const ClassConfig({
     required this.anyMap,
@@ -86,9 +66,33 @@ class ClassConfig implements JsonSerializable {
     required this.genericArgumentFactories,
     required this.ignoreUnannotated,
     required this.includeIfNull,
+    this.converters = const [],
     this.ctorParamDefaults = const {},
   });
 
+  factory ClassConfig.fromJsonSerializable(JsonSerializable config) =>
+      // #CHANGE WHEN UPDATING json_annotation
+      ClassConfig(
+        checked: config.checked ?? ClassConfig.defaults.checked,
+        anyMap: config.anyMap ?? ClassConfig.defaults.anyMap,
+        constructor: config.constructor ?? ClassConfig.defaults.constructor,
+        createFactory:
+            config.createFactory ?? ClassConfig.defaults.createFactory,
+        createToJson: config.createToJson ?? ClassConfig.defaults.createToJson,
+        ignoreUnannotated:
+            config.ignoreUnannotated ?? ClassConfig.defaults.ignoreUnannotated,
+        explicitToJson:
+            config.explicitToJson ?? ClassConfig.defaults.explicitToJson,
+        includeIfNull:
+            config.includeIfNull ?? ClassConfig.defaults.includeIfNull,
+        genericArgumentFactories: config.genericArgumentFactories ??
+            ClassConfig.defaults.genericArgumentFactories,
+        fieldRename: config.fieldRename ?? ClassConfig.defaults.fieldRename,
+        disallowUnrecognizedKeys: config.disallowUnrecognizedKeys ??
+            ClassConfig.defaults.disallowUnrecognizedKeys,
+        // TODO typeConverters = []
+      );
+
   /// An instance of [JsonSerializable] with all fields set to their default
   /// values.
   static const defaults = ClassConfig(
@@ -105,33 +109,18 @@ class ClassConfig implements JsonSerializable {
     includeIfNull: true,
   );
 
-  @override
-  Map<String, dynamic> toJson() => _$JsonSerializableToJson(this);
-
-  @override
-  JsonSerializable withDefaults() => this;
+  JsonSerializable toJsonSerializable() => JsonSerializable(
+        checked: checked,
+        anyMap: anyMap,
+        constructor: constructor,
+        createFactory: createFactory,
+        createToJson: createToJson,
+        ignoreUnannotated: ignoreUnannotated,
+        explicitToJson: explicitToJson,
+        includeIfNull: includeIfNull,
+        genericArgumentFactories: genericArgumentFactories,
+        fieldRename: fieldRename,
+        disallowUnrecognizedKeys: disallowUnrecognizedKeys,
+        // TODO typeConverters = []
+      );
 }
-
-const _$FieldRenameEnumMap = {
-  FieldRename.none: 'none',
-  FieldRename.kebab: 'kebab',
-  FieldRename.snake: 'snake',
-  FieldRename.pascal: 'pascal',
-  FieldRename.screamingSnake: 'screamingSnake',
-};
-
-// #CHANGE WHEN UPDATING json_annotation
-Map<String, dynamic> _$JsonSerializableToJson(JsonSerializable instance) =>
-    <String, dynamic>{
-      'any_map': instance.anyMap,
-      'checked': instance.checked,
-      'constructor': instance.constructor,
-      'create_factory': instance.createFactory,
-      'create_to_json': instance.createToJson,
-      'disallow_unrecognized_keys': instance.disallowUnrecognizedKeys,
-      'explicit_to_json': instance.explicitToJson,
-      'field_rename': _$FieldRenameEnumMap[instance.fieldRename],
-      'generic_argument_factories': instance.genericArgumentFactories,
-      'ignore_unannotated': instance.ignoreUnannotated,
-      'include_if_null': instance.includeIfNull,
-    };

json_serializable/lib/src/type_helpers/json_converter_helper.dart

@@ -17,14 +17,14 @@ import '../utils.dart';
 
 /// A [TypeHelper] that supports classes annotated with implementations of
 /// [JsonConverter].
-class JsonConverterHelper extends TypeHelper {
+class JsonConverterHelper extends TypeHelper<TypeHelperContextWithConfig> {
   const JsonConverterHelper();
 
   @override
   Object? serialize(
     DartType targetType,
     String expression,
-    TypeHelperContext context,
+    TypeHelperContextWithConfig context,
   ) {
     final converter = _typeConverter(targetType, context);
 
@@ -57,7 +57,7 @@ Json? $converterToJsonName<Json, Value>(
   Object? deserialize(
     DartType targetType,
     String expression,
-    TypeHelperContext context,
+    TypeHelperContextWithConfig context,
     bool defaultProvided,
   ) {
     final converter = _typeConverter(targetType, context);
@@ -143,9 +143,18 @@ class _JsonConvertData {
       accessor.isEmpty ? '' : '.$accessor';
 }
 
-_JsonConvertData? _typeConverter(DartType targetType, TypeHelperContext ctx) {
+_JsonConvertData? _typeConverter(
+  DartType targetType,
+  TypeHelperContextWithConfig ctx,
+) {
   List<_ConverterMatch> converterMatches(List<ElementAnnotation> items) => items
-      .map((annotation) => _compatibleMatch(targetType, annotation))
+      .map(
+        (annotation) => _compatibleMatch(
+          targetType,
+          annotation,
+          annotation.computeConstantValue()!,
+        ),
+      )
       .whereType<_ConverterMatch>()
       .toList();
 
@@ -157,6 +166,13 @@ _JsonConvertData? _typeConverter(DartType targetType, TypeHelperContext ctx) {
 
     if (matchingAnnotations.isEmpty) {
       matchingAnnotations = converterMatches(ctx.classElement.metadata);
+
+      if (matchingAnnotations.isEmpty) {
+        matchingAnnotations = ctx.config.converters
+            .map((e) => _compatibleMatch(targetType, null, e))
+            .whereType<_ConverterMatch>()
+            .toList();
+      }
     }
   }
 
@@ -174,13 +190,14 @@ _JsonConvertData? _typeConverterFrom(
   if (matchingAnnotations.length > 1) {
     final targetTypeCode = typeToCode(targetType);
     throw InvalidGenerationSourceError(
-        'Found more than one matching converter for `$targetTypeCode`.',
-        element: matchingAnnotations[1].elementAnnotation.element);
+      'Found more than one matching converter for `$targetTypeCode`.',
+      element: matchingAnnotations[1].elementAnnotation?.element,
+    );
   }
 
   final match = matchingAnnotations.single;
 
-  final annotationElement = match.elementAnnotation.element;
+  final annotationElement = match.elementAnnotation?.element;
   if (annotationElement is PropertyAccessorElement) {
     final enclosing = annotationElement.enclosingElement;
 
@@ -202,8 +219,9 @@ _JsonConvertData? _typeConverterFrom(
   if (reviver.namedArguments.isNotEmpty ||
       reviver.positionalArguments.isNotEmpty) {
     throw InvalidGenerationSourceError(
-        'Generators with constructor arguments are not supported.',
-        element: match.elementAnnotation.element);
+      'Generators with constructor arguments are not supported.',
+      element: match.elementAnnotation?.element,
+    );
   }
 
   if (match.genericTypeArg != null) {
@@ -228,7 +246,7 @@ class _ConverterMatch {
   final DartObject annotation;
   final DartType fieldType;
   final DartType jsonType;
-  final ElementAnnotation elementAnnotation;
+  final ElementAnnotation? elementAnnotation;
   final String? genericTypeArg;
 
   _ConverterMatch(
@@ -242,10 +260,9 @@ class _ConverterMatch {
 
 _ConverterMatch? _compatibleMatch(
   DartType targetType,
-  ElementAnnotation annotation,
+  ElementAnnotation? annotation,
+  DartObject constantValue,
 ) {
-  final constantValue = annotation.computeConstantValue()!;
-
   final converterClassElement = constantValue.type!.element as ClassElement;
 
   final jsonConverterSuper =
@@ -274,7 +291,7 @@ _ConverterMatch? _compatibleMatch(
   }
 
   if (fieldType is TypeParameterType && targetType is TypeParameterType) {
-    assert(annotation.element is! PropertyAccessorElement);
+    assert(annotation?.element is! PropertyAccessorElement);
     assert(converterClassElement.typeParameters.isNotEmpty);
     if (converterClassElement.typeParameters.length > 1) {
       throw InvalidGenerationSourceError(

json_serializable/lib/src/utils.dart

@@ -66,7 +66,7 @@ JsonSerializable _valueForAnnotation(ConstantReader reader) => JsonSerializable(
       includeIfNull: reader.read('includeIfNull').literalValue as bool?,
     );
 
-/// Returns a [JsonSerializable] with values from the [JsonSerializable]
+/// Returns a [ClassConfig] with values from the [JsonSerializable]
 /// instance represented by [reader].
 ///
 /// For fields that are not defined in [JsonSerializable] or `null` in [reader],
@@ -93,6 +93,8 @@ ClassConfig mergeConfig(
           .where((element) => element.hasDefaultValue)
           .map((e) => MapEntry(e.name, e.defaultValueCode!)));
 
+  final converters = reader.read('converters');
+
   return ClassConfig(
     anyMap: annotation.anyMap ?? config.anyMap,
     checked: annotation.checked ?? config.checked,
@@ -109,6 +111,7 @@ ClassConfig mergeConfig(
     ignoreUnannotated: annotation.ignoreUnannotated ?? config.ignoreUnannotated,
     includeIfNull: annotation.includeIfNull ?? config.includeIfNull,
     ctorParamDefaults: paramDefaultValueMap,
+    converters: converters.isNull ? const [] : converters.listValue,
   );
 }
 

json_serializable/pubspec.yaml

@@ -36,3 +36,7 @@ dev_dependencies:
   test_descriptor: ^2.0.0
   test_process: ^2.0.0
   yaml: ^3.0.0
+
+dependency_overrides:
+  json_annotation:
+   path: ../json_annotation