feat: support ignoring custom types that StandardJsonPlugin should le…

…ave as lists (#1296)

Signed-off-by: Nikolas Rimikis <[email protected]>
Co-authored-by: Nikolas Rimikis <[email protected]>

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+# 8.9.0-wip
+
+- Add ignoring types that the StandardJsonPlugin should leave as a List.
+
 # 8.8.1
 
 - Fix codegen for enum wire keys when there is a `$` in the field name.

built_value/lib/serializer.dart

@@ -334,7 +334,7 @@ abstract class PrimitiveSerializer<T> implements Serializer<T> {
   /// the type being serialized is provided in [specifiedType].
   ///
   /// Returns a value that can be represented as a JSON primitive: a boolean,
-  /// an integer, a double, or a String.
+  /// an integer, a double, a String or a List.
   ///
   /// TODO(davidmorgan): document the wire format.
   Object serialize(Serializers serializers, T object,

built_value/lib/standard_json_plugin.dart

@@ -24,11 +24,19 @@ class StandardJsonPlugin implements SerializerPlugin {
   /// The field used to specify the value type if needed. Defaults to `$`.
   final String discriminator;
 
-  // The key used when there is just a single value, for example if serializing
-  // an `int`.
+  /// The key used when there is just a single value, for example if serializing
+  /// an `int`.
   final String valueKey;
 
-  StandardJsonPlugin({this.discriminator = r'$', this.valueKey = ''});
+  /// The types to leave as a list when converting into json.
+  final BuiltSet<Type> typesToLeaveAsList;
+
+  StandardJsonPlugin({
+    this.discriminator = r'$',
+    this.valueKey = '',
+    Iterable<Type>? typesToLeaveAsList,
+  }) : typesToLeaveAsList = BuiltSet<Type>(
+            {BuiltList, BuiltSet, JsonObject, ...?typesToLeaveAsList});
 
   @override
   Object? beforeSerialize(Object? object, FullType specifiedType) {
@@ -41,10 +49,7 @@ class StandardJsonPlugin implements SerializerPlugin {
 
   @override
   Object? afterSerialize(Object? object, FullType specifiedType) {
-    if (object is List &&
-        specifiedType.root != BuiltList &&
-        specifiedType.root != BuiltSet &&
-        specifiedType.root != JsonObject) {
+    if (object is List && !typesToLeaveAsList.contains(specifiedType.root)) {
       if (specifiedType.isUnspecified) {
         return _toMapWithDiscriminator(object);
       } else {

end_to_end_test/lib/records.dart

@@ -66,6 +66,7 @@ abstract class SerializableRecordValue
 
   int get value;
   RecordOfIntInt? get record;
+  RecordOfIntOrList? get intOrList;
 
   factory SerializableRecordValue(
           [void Function(SerializableRecordValueBuilder) updates]) =
@@ -93,3 +94,58 @@ class RecordOfIntIntSerializer implements StructuredSerializer<RecordOfIntInt> {
   @override
   String get wireName => 'RecordOfIntInt';
 }
+
+typedef RecordOfIntOrList = (int?, BuiltList<String>?);
+
+class RecordOfIntOrListSerializer
+    implements PrimitiveSerializer<RecordOfIntOrList> {
+  const RecordOfIntOrListSerializer();
+
+  @override
+  Iterable<Type> get types => const [RecordOfIntOrList];
+
+  @override
+  String get wireName => 'RecordOfIntOrList';
+
+  @override
+  Object serialize(
+    Serializers serializers,
+    RecordOfIntOrList object, {
+    FullType specifiedType = FullType.unspecified,
+  }) {
+    dynamic value;
+    value = object.$1;
+    if (value != null) {
+      return serializers.serialize(value, specifiedType: const FullType(int))!;
+    }
+    value = object.$2;
+    if (value != null) {
+      return serializers.serialize(value,
+          specifiedType: const FullType(BuiltList, [FullType(String)]))!;
+    }
+
+    throw StateError('Tried to serialize without any value.');
+  }
+
+  @override
+  RecordOfIntOrList deserialize(
+    Serializers serializers,
+    Object data, {
+    FullType specifiedType = FullType.unspecified,
+  }) {
+    BuiltList<String>? list;
+    try {
+      list = serializers.deserialize(
+        data,
+        specifiedType: const FullType(BuiltList, [FullType(String)]),
+      )! as BuiltList<String>;
+    } catch (_) {}
+    int? number;
+    try {
+      number = serializers.deserialize(data,
+          specifiedType: const FullType(int))! as int;
+    } catch (_) {}
+
+    return (number, list);
+  }
+}

end_to_end_test/test/records_serializer_test.dart

@@ -4,6 +4,9 @@
 
 import 'dart:convert';
 
+import 'package:built_collection/built_collection.dart';
+import 'package:built_value/serializer.dart';
+import 'package:built_value/standard_json_plugin.dart';
 import 'package:end_to_end_test/errors_matchers.dart';
 import 'package:end_to_end_test/records.dart';
 import 'package:end_to_end_test/serializers.dart';
@@ -63,4 +66,33 @@ void main() {
       expect(serializersWithCustomSerializer.deserialize(serialized), data);
     });
   });
+
+  group('$SerializableRecordValue with a record list value', () {
+    var data = SerializableRecordValue((b) => b
+      ..value = 1
+      ..intOrList = (null, BuiltList(['value0', 'value1', 'value2'])));
+    var serialized = json.decode(json.encode({
+      'value': 1,
+      'intOrList': ['value0', 'value1', 'value2'],
+    })) as Object;
+    var serializersWithCustomSerializer = (serializers.toBuilder()
+          ..addPlugin(
+              StandardJsonPlugin(typesToLeaveAsList: {RecordOfIntOrList}))
+          ..add(RecordOfIntOrListSerializer()))
+        .build();
+
+    test('can be serialized with custom serializer', () {
+      expect(
+          serializersWithCustomSerializer.serialize(data,
+              specifiedType: FullType(SerializableRecordValue)),
+          serialized);
+    });
+
+    test('can be deserialized with custom deserializer', () {
+      expect(
+          serializersWithCustomSerializer.deserialize(serialized,
+              specifiedType: FullType(SerializableRecordValue)),
+          data);
+    });
+  });
 }