Erro in schema oneOf (discriminator)

[pmacaubas]

Describe the bug

I tried to use oneOf and the error happened:

{
"message": "request.body should match exactly one schema in oneOf",
"errors": [
{
"path": ".body",
"message": "should match exactly one schema in oneOf",
"errorCode": "oneOf.openapi.validation"
}
]
}

To Reproduce

app.yaml

This example is the same code that is in OpenApi Specification.

openapi: '3.0.3'
info:
  version: 1.0.0
  title: Swagger 
  description: XXXXX
  termsOfService: http://swagger.io/terms/
  license:
    name: Apache 2.0
    url: https://www.apache.org/licenses/LICENSE-2.0.html
servers:
  #- url: /v1
  - url: /v1
paths:
  /pets:
   post:
      description: Creates a new pet in the store.
      operationId: createPet
      x-eov-operation-id: pets#create ## overrides operationId
      x-eov-operation-handler: api/controllers/pets
      requestBody:
        description: Pet to add to the store
        required: true
        content:
          application/json:
            schema:
              oneOf:
                - $ref: '#/components/schemas/Cat'
                - $ref: '#/components/schemas/Dog'
              discriminator:
                propertyName: pet_type
      responses:
        '200':
          description: Updated
        default:
          description: unexpected error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
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`
          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`
          properties:
            hunts:
              type: boolean
            age:
              type: integer

Request

curl --location --request POST 'http://localhost:10010/v1/pets' \
--header 'Content-Type: application/json' \
--data-raw '{
  "pet_type": "Cat",
  "hunts": true,
  "age": 3
}'

Response ERROR

{
    "message": "request.body should match exactly one schema in oneOf",
    "errors": [
        {
            "path": ".body",
            "message": "should match exactly one schema in oneOf",
            "errorCode": "oneOf.openapi.validation"
        }
    ]
}

Actual behavior

As listed above, the error happened and the schema doesn't validated, because i used oneOf :

This example is the same code that is in OpenApi Specification.

requestBody:
        description: Pet to add to the store
        required: true
        content:
          application/json:
            schema:
              oneOf:
               - $ref: '#/components/schemas/Cat'
               - $ref: '#/components/schemas/Dog'
              discriminator:
                propertyName: pet_type

Expected behavior

I behavior expected is the same the specification for oneOf step:
https://swagger.io/docs/specification/data-models/oneof-anyof-allof-not

In the OpenApi Specification the body bellow is valid :

{
  "pet_type": "Cat",
  "age": 3
}
{
  "pet_type": "Dog",
  "bark": true
}
{
  "pet_type": "Dog",
  "bark": false,
  "breed": "Dingo"
}

Examples and context

This example is the same code that is in OpenApi Specification.
https://swagger.io/docs/specification/data-models/oneof-anyof-allof-not

[cdimascio]

@pmacaubas thanks for the issue. discriminator support is lacking. i have put together a PR that will handle top level discriminators with oneOf and anyOf. I'll get this merged in soon. will love to get your thoughts

[cdimascio]

@pmacaubas initial discriminator support is available in v4.7.0. all use cases are not yet support, but this one is.
please give it a try. as use cases come up, please file them and i'll prioritize
thanks!

here are some examples:

• tests: https://github.com/cdimascio/express-openapi-validator/blob/master/test/one.of.2.spec.ts#L41
• specs: https://github.com/cdimascio/express-openapi-validator/blob/master/test/resources/one.of.2.yaml