List of child objects and kotlin generator

Description

Openapi generator into kotlin-spring generates incorrect kotlin code when I use list (ZOO) of child objects (Cats or Dog) with the common inheritance parent (Pet) in the openapi definition. It creates a data class ZOOAnimalsInner with all fields required, does matter if it is field of Cat, Dog or Pet.

openapi-generator version

6.6.0

OpenAPI declaration file content or url

openapi: 3.0.0

info:

  version: 1.0.0

  title: allOf test

  description: based on https://swagger.io/docs/specification/data-models/oneof-anyof-allof-not/

paths:

  /zoo:

    patch:

      requestBody:

        content:

          application/json:

            schema:

              $ref: '#/components/schemas/ZOO'

      responses:

        '200':

          description: Updated

components:

  schemas:

    Pet:

      type: object

      required:

        - pet_type

      properties:

        pet_type:

          type: string

      discriminator:

        propertyName: pet_type

    Dog:     # "Dog" is a value for the pet_type property (the discriminator value)

      allOf: # Combines the main `Pet` schema with `Dog`-specific properties

        - $ref: '#/components/schemas/Pet'

        - type: object

          # all other properties specific to a `Dog`

          required:

            - bark

            - breed

          properties:

            bark:

              type: boolean

            breed:

              type: string

              enum: [Dingo, Husky, Retriever, Shepherd]

    Cat:     # "Cat" is a value for the pet_type property (the discriminator value)

      allOf: # Combines the main `Pet` schema with `Cat`-specific properties

        - $ref: '#/components/schemas/Pet'

        - type: object

          # all other properties specific to a `Cat`

          required:

            - hunts

            - age

          properties:

            hunts:

              type: boolean

            age:

              type: integer

    ZOO:

      type: object

      properties:

        animals:

          type: array

          items:

            oneOf:

              - $ref: '#/components/schemas/Dog'

              - $ref: '#/components/schemas/Cat'

Suggest a fix

Fields of Cat and fields of Dog shlould be optional in the generated class ZOOAnimalsInner.

Use the supplied OpenAPI declaration with the Kotlin Spring generator at version 6.6.0 and inspect the generated ZOOAnimalsInner class. Trace how the oneOf array items and inherited required fields are represented, then verify that Cat and Dog fields are optional in the generated class.