Problems generating classes when complexe object in constructor

[chrisDK1977]

As I got no answer on that on stackoverflow I hope for an answer here.

When extending a class and serializing a complexe object I get some problems. Ist seems the problem only existing when extending and having the complexe object in the constructor:

import 'package:json_annotation/json_annotation.dart';
part 'app_user.g.dart';

@JsonSerializable(explicitToJson: true)
class AppUser extends BaseUser{
  String name;


  AppUser(this.name, avatar) : super(avatar);

  factory AppUser.fromJson(Map<String, dynamic> json) => _$AppUserFromJson(json);
  Map<String, dynamic> toJson() => _$AppUserToJson(this);
}

class BaseUser{
  AvatarConfiguration? avatar;

  BaseUser(AvatarConfiguration avatar);
}

@JsonSerializable()
class AvatarConfiguration{
  @JsonKey(name: "he")
  int head;
  @JsonKey(name: "ha")
  int hair;
  @JsonKey(name: "no")
  int nose;
  @JsonKey(name: "mo")
  int mouth;
  @JsonKey(name: "ey")
  int eye;


  AvatarConfiguration(this.head, this.hair, this.nose, this.mouth, this.eye);

  factory AvatarConfiguration.fromJson(Map<String, dynamic> json) => _$AvatarConfigurationFromJson(json);

  Map<String, dynamic> toJson() => _$AvatarConfigurationToJson(this);

}

I get that generated:

part of 'app_user.dart';

// **************************************************************************
// JsonSerializableGenerator
// **************************************************************************

AppUser _$AppUserFromJson(Map<String, dynamic> json) => AppUser(
      json['name'] as String,
      json['avatar'],
    );

Map<String, dynamic> _$AppUserToJson(AppUser instance) => <String, dynamic>{
      'avatar': instance.avatar?.toJson(),
      'name': instance.name,
    };

AvatarConfiguration _$AvatarConfigurationFromJson(Map<String, dynamic> json) =>
    AvatarConfiguration(
      json['he'] as int,
      json['ha'] as int,
      json['no'] as int,
      json['mo'] as int,
      json['ey'] as int,
    );

Map<String, dynamic> _$AvatarConfigurationToJson(
        AvatarConfiguration instance) =>
    <String, dynamic>{
      'he': instance.head,
      'ha': instance.hair,
      'no': instance.nose,
      'mo': instance.mouth,
      'ey': instance.eye,
    };

and

json['avatar'],

is not what I expect.

When not extending the class

@JsonSerializable(explicitToJson: true)
class AppUser{
  String name;
  AvatarConfiguration? avatar;

  AppUser(this.name, this.avatar);

  factory AppUser.fromJson(Map<String, dynamic> json) => _$AppUserFromJson(json);
  Map<String, dynamic> toJson() => _$AppUserToJson(this);
}

I get what I expect:

// **************************************************************************
// JsonSerializableGenerator
// **************************************************************************

AppUser _$AppUserFromJson(Map<String, dynamic> json) => AppUser(
      json['name'] as String,
      json['avatar'] == null
          ? null
          : AvatarConfiguration.fromJson(
              json['avatar'] as Map<String, dynamic>),
    );

Map<String, dynamic> _$AppUserToJson(AppUser instance) => <String, dynamic>{
      'name': instance.name,
      'avatar': instance.avatar?.toJson(),
    };
...

Can anyone tell me if that is a bug or does it make sense how json_serializable is working???

Version is 6.5.3

[√] Flutter (Channel stable, 3.3.5, on Microsoft Windows [Version 10.0.19044.2130], locale de-DE)
• Flutter version 3.3.5 on channel stable at C:\SDKs\flutter_latest\flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision d9111f6402 (8 days ago), 2022-10-19 12:27:13 -0700
• Engine revision 3ad69d7be3
• Dart version 2.18.2
• DevTools version 2.15.0

...

[kevmoo]

What is Avatar? It needs to have a fromJson and toJson on it. Or it's just treated like an opaque object.

[github-actions]

Without additional information we're not able to resolve this issue, so it will be closed at this time. You're still free to add more info and respond to any questions above, though. We'll reopen the case if you do. Thanks for your contribution!

[chrisDK1977]

@kevmoo
Avatar is of Type AvatarConfiguration which has the required methods posted in the question

AvatarConfiguration _$AvatarConfigurationFromJson(Map<String, dynamic> json) =>
    AvatarConfiguration(
      json['he'] as int,
      json['ha'] as int,
      json['no'] as int,
      json['mo'] as int,
      json['ey'] as int,
    );

Map<String, dynamic> _$AvatarConfigurationToJson(
        AvatarConfiguration instance) =>
    <String, dynamic>{
      'he': instance.head,
      'ha': instance.hair,
      'no': instance.nose,
      'mo': instance.mouth,
      'ey': instance.eye,
    };

[kevmoo]

I just put this code

@JsonSerializable(explicitToJson: true)
class AppUser extends BaseUser {
  String name;

  AppUser(this.name, super.avatar);

  factory AppUser.fromJson(Map<String, dynamic> json) =>
      _$AppUserFromJson(json);
  Map<String, dynamic> toJson() => _$AppUserToJson(this);
}

class BaseUser {
  AvatarConfiguration? avatar;

  BaseUser(this.avatar);
}

@JsonSerializable()
class AvatarConfiguration {
  @JsonKey(name: 'he')
  int head;
  @JsonKey(name: 'ha')
  int hair;
  @JsonKey(name: 'no')
  int nose;
  @JsonKey(name: 'mo')
  int mouth;
  @JsonKey(name: 'ey')
  int eye;

  AvatarConfiguration(this.head, this.hair, this.nose, this.mouth, this.eye);

  factory AvatarConfiguration.fromJson(Map<String, dynamic> json) =>
      _$AvatarConfigurationFromJson(json);

  Map<String, dynamic> toJson() => _$AvatarConfigurationToJson(this);
}

Got this generated

AppUser _$AppUserFromJson(Map<String, dynamic> json) => AppUser(
      json['name'] as String,
      json['avatar'] == null
          ? null
          : AvatarConfiguration.fromJson(
              json['avatar'] as Map<String, dynamic>),
    );

Map<String, dynamic> _$AppUserToJson(AppUser instance) => <String, dynamic>{
      'avatar': instance.avatar?.toJson(),
      'name': instance.name,
    };

AvatarConfiguration _$AvatarConfigurationFromJson(Map<String, dynamic> json) =>
    AvatarConfiguration(
      json['he'] as int,
      json['ha'] as int,
      json['no'] as int,
      json['mo'] as int,
      json['ey'] as int,
    );

Map<String, dynamic> _$AvatarConfigurationToJson(
        AvatarConfiguration instance) =>
    <String, dynamic>{
      'he': instance.head,
      'ha': instance.hair,
      'no': instance.nose,
      'mo': instance.mouth,
      'ey': instance.eye,
    };

Maybe you need to add in the type in the argument passed to the base type?