False Positives in oas3-unused-component Rule for Schemas Referenced via oneOf, Vendor Extensions, and Property Access

[BentEngbers]

In the following cases, Vacuum incorrectly flags the schemas a, b, and c as false positives when using the oas3-unused-component rule with OpenAPI version 3.1.0.

Cases

1. oneOf Schema

   oneOf:
     - $ref: "#/components/schemas/a"
     - type: "null"

   Vacuum incorrectly marks a as unused when referenced within a oneOf structure.

2. Vendor Extension

   x-publish: false
   $ref: '#/components/schemas/b'

   Vacuum mistakenly identifies b as unused when it is referenced alongside a vendor extension.

3. Property Access

openapi: 3.1.0
paths:
  /example:
    get:
      operationId: example
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/response/properties/foo"
components:
  schemas:
    response:
      type: object
      properties:
        foo:
          type: string

Vacuum incorrectly flags example as unused when accessing a property within the schema:

 `#/components/schemas/response` is potentially unused or has been orphaned          | oas3-unused-component

[daveshanley]

Can you provide a snippet that we can run to validate this? trying to re-create things from single lines out of context takes a long time.