component-name-unique

Verifies component names are unique.

OAS	Compatibility
2.0	❌
3.0	✅
3.1	✅

API design principles

When generating code based on an OpenAPI description, there are various different problems when component names are not unique through the whole spec.

schema: The code generator creates a class for each schema. If they are not uniquely named, the generator appends numbers. These numbers are non-deterministic. By adding a new schema with the same component name it could change the name (appended number) of another one.
parameter: The code generator creates a class for each parameter. If they are not uniquely named, the generator appends numbers. These numbers are non-deterministic. By adding a new parameter with the same component name it could change the name (appended number) of another one.
response: The code generator tends to reuse the first one and drops the other ones with the same component name.
requestBody: The code generator tends to reuse the first one and drops the other ones with the same component name.

This clearly is not optimal. Having unique component names prevents these problems.

Configuration

Option	Type	Description
severity	string	Possible values: `off`, `warn`, `error`. Default `off` (in `recommended` configuration).
schemas	string	Possible values: `off`, `warn`, `error`. Default: not set.
parameters	string	Possible values: `off`, `warn`, `error`. Default: not set.
responses	string	Possible values: `off`, `warn`, `error`. Default: not set.
requestBodies	string	Possible values: `off`, `warn`, `error`. Default: not set.

An example configuration:

rules:
  component-name-unique:
    schemas: error
    parameters: off
    responses: warn
    requestBodies: warn

Examples

Given this configuration:

rules:
  component-name-unique: error

Example of incorrect schema files

file1.yaml:

components:
  schemas:
    FooSchema:
      type: object
      properties:
        field:
          $ref: './file2.yaml#/components/schemas/FooSchema'

file2.yaml:

components:
  schemas:
    FooSchema:
      type: object
      properties:
        otherField:
          type: string

Example of correct schema files