Reproducible repo for Fastify Shared Response schema

See code: app.js & routes/root.js

1. npm install
2. npm run dev
3. Go to: http://127.0.0.1:3000/docs
4. See error message appear in Swagger:

Resolver error at paths./.get.responses.500.content.application/json.schema.$ref
Could not resolve reference: Could not resolve pointer: /components/schemas/def-0/definitions/internalServerErrorResponse does not exist in document

(No errors appear in the console log)

Because Swagger is NOT built to use definitions via addSchema for response objects, instead Swagger is built to use components -> responses schemas for shared responses objects instead.

---

Swagger support components with responses this during OpenAPI spec definition (Fastify Swagger doesn't support this). Example ofa such an OpenAPI document:

{
    openapi: '3.0.0',
    info: {
        title: 'Example...'
    },
    components: {
        responses: {
            internalServerErrorResponse: {
                description: "500 Internal Server Error",
                content: {
                    "application/json": {
                        "schema": {
                            "type": "object",
                        }
                    }
                }
            }
        }
    }
}

Such a component response object above could be used for reusability, if that was supported by Fastify Swagger.