Null in enum not handled correctly

[dickermoshe]

Details

components:
  schemas:
    AnyOfTest:
      anyOf:
      - type: string
      - $ref: '#/components/schemas/EnumString'
      - $ref: '#/components/schemas/EnumNullString'
      - $ref: '#/components/schemas/EnumNull'
      description: to test anyOf (string, enum string)
    EnumNull:
      enum:
      - null
      type: string
    EnumNullString:
      enum:
      - 'null'
      type: string
    EnumString:
      enum:
      - A
      - B
      type: string
info:
  license:
    name: MIT
  title: Example
  version: 1.0.0
openapi: 3.0.1
paths:
  /person/display/{personId}:
    get:
      operationId: list
      parameters:
      - description: The id of the person to retrieve
        in: path
        name: personId
        required: true
        schema:
          type: string
      responses:
        '200':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/AnyOfTest'
          description: OK
servers:
- url: http://api.example.xyz/v1

[walsha2]

EnumNull:
  enum:
  - null
  type: string

I am not sure I follow, what does this even represent as a Dart class? How is this a proper enum definition?

I am not sure this edge case is even worth spending time coding up and protecting for... Unless you have a real world example that is not an edge case test scheme from OpenAPI repo?

[dickermoshe]

It's more common than you think.
The example I posted is stupid, but this update in 3.1 added full support with the json schema which does

EnumNull:
  enum:
  - null
  - ice_cream
  - yogurt
  type: string

It used to be

EnumNull:
  enum:
  - ice_cream
  - yogurt
  type: string
  nullable: true

OAI/OpenAPI-Specification#1900 (comment)

[dickermoshe]

Proposal:
swagger-parser add an unknown value that makes the api backwards compatible.
So even if this isn't fixed, it will still wont throw when null is returned
what do you think?

// coverage:ignore-file
// GENERATED CODE - DO NOT MODIFY BY HAND
// ignore_for_file: type=lint, unused_import

import 'package:freezed_annotation/freezed_annotation.dart';

@JsonEnum()
enum Status {
  @JsonValue('available')
  available('available'),
  @JsonValue('pending')
  pending('pending'),
  @JsonValue('sold')
  sold('sold'),
  /// Default value for all unparsed values, allows backward compatibility when adding new values on the backend.
  $unknown(null);

  const Status(this.json);

  factory Status.fromJson(String json) => values.firstWhere(
        (e) => e.json == json,
        orElse: () => $unknown,
      );

  final String? json;
}

[walsha2]

Ok so it just means that the enum itself is nullable, not that the individual enum value is null. I dont really like that spec definition.

There is a "simple" fix for this, I believe. I can take care of it.