oas30-enum-null-coercion

Finds non-null enum values that do not satisfy their OpenAPI 3.0 schema.

Attribute	Value
Category	Schema
Maturity	Platinum
OpenAPI	OpenAPI 3.0
Starter	Off
Lenient	Warning
Recommended–Complete	Error

Intent

OpenAPI 3.0 tooling can coerce enum values inconsistently. Keeping every value compatible with its declared schema prevents ambiguous generated models.

Flags

An OpenAPI 3.0 enum containing a non-null value that conflicts with the schema's type or supported constraints. Schemas already permitting null are excluded from this check.

Does not flag

Matching values, nullable schemas, schemas without a declared non-null type, or OpenAPI 3.1 documents.

See it fail

Choice:
  type: string
  enum: [1, 2]

Diagnostic: One or more enum values do not match the declared schema type

Fix it

Choice:
  type: string
  enum: ['1', '2']

Configure

profiles:
  default:
    rules:
      extends: [recommended]
      override:
        oas30-enum-null-coercion: warn

Nearby: enum-nullability-coercion, enum-value-schema-mismatch.