External references using anchors resulting in double references in generated typescript

[pvanagtmaal]

Description

In a slightly complex schema with multiple files and using YAML anchors to define objects, something fishy is going on with the external schemas in the generated typescript, with multiple self-references where there should be only one.

If you can point me in the right direction, I'd be more than willing to submit a PR :)

Name	Version
openapi-typescript	6.4.0
Node.js	18.10.0
OS + version	macOS 13

Reproduction

Add the following test files:

# anchor-with-ref-test.yaml
openapi: "3.0"
info:
  title: test
  version: "1.0"
paths:
  /:
    get:
      responses:
        200:
          description: OK
components:
  schemas:
    partialTest:
      type: object
      properties: &testProperties
        metadata:
          $ref: '#/components/schemas/metadata'
      additionalProperties: false
    test:
      type: object
      properties: *testProperties
      additionalProperties: false
    metadata:
      type: object
      additionalProperties: true

# anchor-with-ref-test-2.yaml
openapi: "3.0"
info:
  title: test
  version: "1.0"
paths:
  /:
    get:
      responses:
        200:
          description: OK
components:
  schemas:
    obj:
      $ref: './anchor-with-ref-test.yaml#/components/schemas/test'

Expected result

export interface paths {
  "/": {
    get: {
      responses: {
        /** @description OK */
        200: never;
      };
    };
  };
}
export type webhooks = Record<string, never>;
export interface components {
  schemas: {
    obj: external["anchor-with-ref-test.yaml"]["components"]["schemas"]["test"];
  };
  responses: never;
  parameters: never;
  requestBodies: never;
  headers: never;
  pathItems: never;
}

export interface external {
  "anchor-with-ref-test.yaml": {
    paths: {
      "/": {
        get: {
          responses: {
            /** @description OK */
            200: never;
          };
        };
      };
    };
    webhooks: Record<string, never>;
    components: {
      schemas: {
        partialTest: {
          // actual: metadata?: external["anchor-with-ref-test.yaml"]["external"]["anchor-with-ref-test.yaml"]["components"]["schemas"]["metadata"];
          metadata?: external["anchor-with-ref-test.yaml"]["components"]["schemas"]["metadata"];
        };
        test: {
          // actual: metadata?: external["anchor-with-ref-test.yaml"]["external"]["anchor-with-ref-test.yaml"]["components"]["schemas"]["metadata"];
          metadata?: external["anchor-with-ref-test.yaml"]["components"]["schemas"]["metadata"];
        };
        metadata: {
          [key: string]: unknown;
        };
      };
      responses: never;
      parameters: never;
      requestBodies: never;
      headers: never;
      pathItems: never;
    };
  };
}

export type operations = Record<string, never>;

Checklist

• My OpenAPI schema passes the Redocly validator (npx @redocly/cli@latest lint)
• I’m willing to open a PR (see CONTRIBUTING.md)

[pvanagtmaal]

Seems like the anchor doesn't even have to be referenced, as long as you use it somewhere...
The anchor-with-ref-test.yaml would thus become

openapi: "3.0"
info:
  title: test
  version: "1.0"
paths:
  /:
    get:
      responses:
        200:
          description: OK
components:
  schemas:
    test:
      type: object
      properties: &testProperties
        metadata:
          $ref: '#/components/schemas/metadata'
      additionalProperties: false
    anchorTest:
      type: object
      additionalProperties: false
      properties: *testProperties
    metadata:
      type: object
      additionalProperties: true

and the output would still have the double reference