openapi: 3.0.0
info:
  version: 0.0.1
  title: test
paths:
  /foo:
    post:
      requestBody:
        $ref: '#/components/requestBodies/FooRequest'
      responses:
        '200':
          $ref: '#/components/responses/FooResponse'
      tags:
        - Foos
      operationId: getFoo
components:
  schemas:
    PetName:
      type: object
      properties:
        name:
          type: string
        nickname:
          type: string
          nullable: true
  requestBodies:
    FooRequest:
      required: true
      content:
        application/json:
          schema:
            type: object
            properties:
              name:
                type: string
                nullable: true
              pet:
                allOf:
                  - $ref: '#/components/schemas/PetName'
                  - type: object
                    properties:
                      favorite_foods:
                        type: array
                        items:
                          type: string
                          nullable: true
  responses:
    FooResponse:
      description: Foo
      content:
        application/json:
          schema:
            allOf:
              - $ref: '#/components/schemas/PetName'
              - type: object
                properties:
                  name:
                    type: string
                    nullable: true