openapi-generator: [JAVA] discriminator.mapping is not supported (in generated model)

Description

spec: https://swagger.io/docs/specification/data-models/inheritance-and-polymorphism/ mapping can be specified in discriminator:

discriminator:
  propertyName: petType
  mapping:
    dogggg: '#/components/schemas/Dog'
    catttt: '#/components/schemas/Cat'

Currently it’s not taken in account when generating model (it’s not for Java, may be for every other language too)

openapi-generator version

3.1.0-SNAPSHOT

OpenAPI declaration file content or url

openapi: "3.0.0"
info:
  version: 1.0.0
  title: Swagger Petstore
  license:
    name: MIT
servers:
  - url: http://petstore.swagger.io/v1
paths:
  /pets:
    get:
      summary: List all pets
      operationId: listPets
      tags:
        - pets
      parameters:
        - name: limit
          in: query
          description: How many items to return at one time (max 100)
          required: false
          schema:
            type: integer
            format: int32
      responses:
        '200':
          description: A paged array of pets
          headers:
            x-next:
              description: A link to the next page of responses
              schema:
                type: string
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Pets"
        default:
          description: unexpected error
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
    post:
      summary: Create a pet
      operationId: createPets
      tags:
        - pets
      responses:
        '201':
          description: Null response
        default:
          description: unexpected error
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
  /pets/{petId}:
    get:
      summary: Info for a specific pet
      operationId: showPetById
      tags:
        - pets
      parameters:
        - name: petId
          in: path
          required: true
          description: The id of the pet to retrieve
          schema:
            type: string
      responses:
        '200':
          description: Expected response to a valid request
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Pets"
        default:
          description: unexpected error
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
components:
  schemas:
    Pet:
      type: object
      discriminator:
        propertyName: petType
        mapping:
          dogggg: '#/components/schemas/Dog'
          catttt: '#/components/schemas/Cat'
      properties:
        name:
          type: string
        petType:
          type: string
      required:
      - name
      - petType
    Cat:
      description: A representation of a cat
      allOf:
      - $ref: '#/components/schemas/Pet'
      - type: object
        properties:
          huntingSkill:
            type: string
            description: The measured skill for hunting
            enum:
            - clueless
            - lazy
            - adventurous
            - aggressive
        required:
        - huntingSkill
    Dog:
      description: A representation of a dog
      allOf:
      - $ref: '#/components/schemas/Pet'
      - type: object
        properties:
          packSize:
            type: integer
            format: int32
            description: the size of the pack the dog is from
            default: 0
            minimum: 0
        required:
        - packSize
    Pets:
      type: array
      items:
        $ref: "#/components/schemas/Pet"
    Error:
      required:
        - code
        - message
      properties:
        code:
          type: integer
          format: int32
        message:
          type: string

Command line used for generation

java -jar … generate -i api.yaml -g java --library resttemplate

Steps to reproduce

Generate model Here is what’s generated in Pet.java:

@JsonSubTypes({
  @JsonSubTypes.Type(value = Cat.class, name = "Cat"),
  @JsonSubTypes.Type(value = Dog.class, name = "Dog"),
})

Related issues/PRs

Suggest a fix/enhancement

Should generate model like this:

@JsonSubTypes({
  @JsonSubTypes.Type(value = Cat.class, name = "catttt"),
  @JsonSubTypes.Type(value = Dog.class, name = "dogggg"),
})

About this issue

Original URL
State: open
Created 6 years ago
Reactions: 7
Comments: 25 (19 by maintainers)

Commits related to this issue

patched openapi generator with ldap identity provider. openapi.generator does not play well with discriminator(s) from the openapi spec. related issues: https://github.com/OpenAPITools/openapi-gener... — committed to appgate/terraform-provider-appgatesdp by dlnilsson 4 years ago

Most upvoted comments

This is also biting me with the following spec and 4.2.2:

OutputFormat:
      type: object
      required:
        - type
      properties:
        type:
          type: string
      discriminator:
        propertyName: type
        mapping:
          outputKeyValueLabel: '#/components/schemas/OutputKeyValueLabel'
          outputIdLabel: '#/components/schemas/OutputIdLabel'
    OutputKeyValueLabel:
      allOf:
        - $ref: '#/components/schemas/OutputFormat'
        - type: object
          properties:
            keyLabel:
              type: string
              example: PETS
            valueLabel:
              type: string
              example: DOGS
          required:
            - keyLabel
    OutputIdLabel:
      allOf:
        - $ref: '#/components/schemas/OutputFormat'
        - type: object
          properties:
            idLabel:
              type: string
              example: MM1234
          required:
            - idLabel

this gives

public class OutputFormat {
  public static final String SERIALIZED_NAME_TYPE = "type";
  @SerializedName(SERIALIZED_NAME_TYPE)
  private String type;

  public OutputFormat() {
    this.type = this.getClass().getSimpleName();
  }

  public OutputFormat type(String type) {
    
    this.type = type;
    return this;
  }
...

and the discriminator is set to the class’s name instead of the specified mapping. There also isn’t any JsonTypeInfo annotations on the classes.

davinchia on Dec 30, 2019

Note that if you upgrade to an OpenAPI specification instead of swagger 2.0 and use f.e. the <library>jersey2</library> then it does work. Also check out this stackoverflow post: https://stackoverflow.com/questions/59252417/generate-a-property-as-schema-definition-in-openapi-3-0

ivarreukers on Dec 30, 2019

@jmini submitted https://github.com/OpenAPITools/openapi-generator/pull/536

some concerns about the PR:

Deleted modelInheritanceSupportInGson cause it doesn’t do anything besides calculating children (for annotation) - not 100% sure about this. Pls, review
Removing discriminator field requires more information. Will add later

0v1se on Jul 11, 2018