spec.yaml

openapi: "3.0.3"
info:
  title: MS Pet API
  version: 1.0.0
  description: De API for testing the discriminator in openapi 6
paths:
  /api/projects:
    get:
      summary: get a pet
      operationId: getPets
      tags:
        - pets
      responses:
        200:
          description: Succes respons
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/PetResponse'

components:
  schemas:
    PetResponse:
      oneOf:
        - $ref: '#/components/schemas/Cat'
        - $ref: '#/components/schemas/Dog'
        - $ref: '#/components/schemas/Lizard'
      discriminator:
        propertyName: petType
    Cat:
      type: object
      # all other properties specific to a `Cat`
      required:
        - petType
      properties:
        catName:
          type: string
        petType:
          type: string
    Dog:
      type: object
      # all other properties specific to a `Dog`
      required:
        - petType
      properties:
        bark:
          type: string
        petType:
          type: string
    Lizard:
      type: object
      # all other properties specific to a `Lizard`
      required:
        - petType
      properties:
        lovesRocks:
          type: boolean
        petType:
          type: string