allof-contradictory-constraints

Finds an allOf whose branches give a required property no possible value.

Attribute	Value
Category	Schema
Maturity	Platinum
OpenAPI	Swagger 2.0; OpenAPI 3.0, 3.1, 3.2
Starter	Off
Lenient	Warning
Recommended–Complete	Error

Intent

Every allOf branch must hold at the same time. Non-overlapping enum or const values for a required property make the combined schema impossible to satisfy.

Flags

Two or more inline or referenced allOf branches that constrain the same required property to finite, non-overlapping values. A property counts as required when the parent requires it, or every constraining branch does.

Does not flag

Optional properties, value sets with at least one shared value, or constraints that are not expressed with enum or const.

See it fail

Pet:
  type: object
  required: [kind]
  allOf:
    - type: object
      properties:
        kind:
          type: string
          enum: [cat]
    - type: object
      properties:
        kind:
          type: string
          enum: [dog]

kind must be both cat and dog, which is impossible.

Fix it

Give the branches an overlapping value, or use oneOf when they represent alternatives:

Pet:
  oneOf:
    - type: object
      required: [kind]
      properties:
        kind:
          type: string
          enum: [cat]
    - type: object
      required: [kind]
      properties:
        kind:
          type: string
          enum: [dog]

Configure

profiles:
  default:
    rules:
      extends: [recommended]
      override:
        allof-contradictory-constraints: warn

Nearby: enum-no-matching-values, duplicate-oneof-discriminator.