Inheritance using 'allOf' seems broken

Problems with inheritance and overrides.

Q	A
Bug or feature request?	Bug
Which Swagger/OpenAPI version?	2.0
Which Swagger-UI version?	Using Swagger-UI 3.X, via https://editor.swagger.io
How did you install Swagger-UI?	N/A
Which browser & version?	Google Chrome 60.0.3112.113 (Official Build) (64-bit)
Which operating system?	macOS

Demonstration API definition

swagger: "2.0"

info:
  version: 1.0.0
  title: Test
securityDefinitions:
  basicAuth:
    type: basic

paths:
  /bban/validate:
    post:
      produces:
        - application/json
      responses:
        200:
          description: OK
          schema:
            allOf:
              - $ref: '#/definitions/SwedenBBANValidationResponse'
              - $ref: '#/definitions/NorwayBBANValidationResponse'

definitions:
  BBANValidationResponse:
    description: |
      A discriminated object with variants:
      - <a href="#SwedenBBANValidationResponse">SwedenBBANValidationResponse</a>
      - <a href="#NorwayBBANValidationResponse">NorwayBBANValidationResponse</a>
    type: object
    properties:
      common_property:
        type: boolean
      enums:
        type: string
        enum:
          - enum_override_1
          - enum_override_2
        description: Enum override

  SwedenBBANValidationResponse:
    type: object
    description: Specific information for the `Sweden` type of BBANValidationResponse
    allOf:
      - $ref: "#/definitions/BBANValidationResponse"
      - type: object
        properties:
          sweden_specific_property:
            type: string
          enums:
            type: string
            enum:
              - sweden_enum_1
              - sweden_enum_2
            description: Sweden description

  NorwayBBANValidationResponse:
    type: object
    description: Specific information for the `Norway` type of BBANValidationResponse
    allOf:
      - $ref: "#/definitions/BBANValidationResponse"
      - type: object
        properties:
          norway_specific_property:
            type: string
          enums:
            type: string
            enum:
              - norway_enum_1
              - norway_enum_2
            description: Norway description

Expected Behavior

I want ‘Model’ in the API definition to show the enums fields as a combination of the fields of its inherited definitions (SwedenBBANValidationResponse and NorwayBBANValidationResponse).

And allow an enums specification on the parent to override the children if used.

Current Behavior

Currently, enums shows values and description only from one of its children, seemingly arbitrarily chosen.

There is no way to override the bleed-through by specifying a values on the parent.

Possible Solution

Context

[webron]

@HaraldNordgren I’m sorry, but @hkosova is right. allOf does not merge schemas, it checks each one of those individually. In effect, nothing would validate against any of the schemas you provided in your sample, except for BBANValidationResponse, because you have conflicting enum definitions in all the other allOf instances.

When we render allOfin Swagger-UI - it is indeed a ‘merge’ of a sort - this is because it’s easier to display and understand, and in most cases, when there are no conflicts, works well. We do have a way of producing a non-merged version of it, even though that’s not exposed right now.

I’m afraid there’s nothing to fix here. @owenconti, your PR is not needed unfortunately.

[owenconti]

Hi @HaraldNordgren - I believe I have a fix for this issue. The fix is in the swagger-js repository. You can track the PR here: https://github.com/swagger-api/swagger-ui/issues/3674