Handle properties in Model Composition - using allOf in OpenAPI

[ddobrin]

Properties need to be combined, as per spec:
Inheritance and Polymorphism - Model Composition

In the example below the ExtendedErrorModel schema includes its own properties and properties inherited from BasicErrorModel:

components:
  schemas:
    BasicErrorModel:
      type: object
      required:
        - message
        - code
      properties:
        message:
          type: string
        code:
          type: integer
          minimum: 100
          maximum: 600
    ExtendedErrorModel:
      allOf:     # Combines the BasicErrorModel and the inline model
        - $ref: '#/components/schemas/BasicErrorModel'
        - type: object
          required:
            - rootCause
          properties:
            rootCause:
              type: string

Note: current implementation creates a new object as listed under $ref and refers to it in the POJO.

[ddobrin]

Handle properties in Model Composition - using allOf in OpenAPI