spec-discriminator-defaultMapping

Requires a discriminator's defaultMapping to identify an existing schema component.

Attribute	Value
Category	Schema
Maturity	Platinum
OpenAPI	OpenAPI 3.2
Starter–Lenient	Off
Recommended–Strict	Warning
Complete	Error

Intent

defaultMapping provides the fallback schema when no explicit discriminator mapping matches. A missing target makes that fallback unusable.

Flags

An OpenAPI 3.2 discriminator whose defaultMapping value matches neither a full component name nor the final schema name in the reference-like value.

Does not flag

Existing component targets, discriminators without defaultMapping, or documents earlier than OpenAPI 3.2.

See it fail

components:
  schemas:
    Animal:
      discriminator:
        propertyName: kind
        defaultMapping: '#/components/schemas/UnknownAnimal'

UnknownAnimal is not defined under components.schemas.

Fix it

Point to an existing component:

components:
  schemas:
    Animal:
      discriminator:
        propertyName: kind
        defaultMapping: '#/components/schemas/GenericAnimal'
    GenericAnimal:
      type: object

Configure

Rule IDs are case-sensitive; preserve the capital M in defaultMapping.

profiles:
  default:
    rules:
      extends: [recommended]
      override:
        spec-discriminator-defaultMapping: error

Nearby: duplicate-oneof-discriminator.