schema-discriminator-defined

Since 0.0.1 · fixed by --fix

This rule ensures that whenever a schema object defines a oneOf clause, it also defines a discriminator property.

Rule Details

The schema-discriminator-defined rule is designed to ensure that all schema objects that define a oneOf clause also define the discriminator property. The discriminator property is used to aid in the deserialization of oneOf schemas.

Configuration

None.

Examples

Good.

components:
  schemas:
    Pet:
      type: object
      discriminator:
        propertyName: petType
      oneOf:
        - $ref: "#/components/schemas/Cat"
        - $ref: "#/components/schemas/Dog"

Bad. It is not obvious when a pet is a cat, and when it is a dog.

components:
  schemas:
    Pet:
      type: object
      oneOf:
        - $ref: "#/components/schemas/Cat"
        - $ref: "#/components/schemas/Dog"

When Not to Use It

We recommend to always enable this rule.

Automatic fixes

When invoked with --fix, this rule adds discriminator.propertyName only when every oneOf alternative exposes one shared property with distinct const values. All other discriminator choices remain manual.

Compatibility

This rule is compatible with all OpenAPI 3.x versions.