Enum serialization creates nullable type for non-nullable enums

[ssabdb]

Using an Enum as a key in a map yields a field with type <String?, dynamic> (rather than the expected <String, dynamic>.

import 'package:json_annotation/json_annotation.dart';

part 'shape_sorter.g.dart';

enum shapeProperty { size, color }

@JsonSerializable()
class ShapeSorter {
  Map<shapeProperty, String> shapeProperties;

  ShapeSorter(this.shapeProperties);
}

This leads to the generated code;

Map<String, dynamic> _$ShapeSorterToJson(ShapeSorter instance) =>
    <String, dynamic>{
      'shapeProperties': instance.shapeProperties
          .map((k, e) => MapEntry(_$shapePropertyEnumMap[k], e)),
    };
    

const _$shapePropertyEnumMap = {
  shapeProperty.size: 'size',
  shapeProperty.color: 'color',
};

This is because _$shapePropertyEnumMap[k] yields type String?, even though the value - I think - is guaranteed to exist in the map. This isn't a major problem unless you have post processing (I'm using FakeFirebaseFirestore, but there could be otherwise).

This causes a problem with anything which is doing null-aware runtime typechecking for Map<String, dynamic>.

json_serializable: "6.2.0"

[ssabdb]

Potentially resolved by #1146