fix: soft fail fallback response description lookups

[samchungy]

I tried fixing this issue in my library as raised in samchungy/fastify-zod-openapi#172

My library dynamically generates $refs for users so they don't need to register anything upfront and plops them into the components section at the end.

As an example, my users will fill in the following:

responses: {
  200: z.string().openapi({ ref: 'Foo' })
}

The transform hook will output:

responses: {
  200: {
    $ref: '#/components/schemas/Foo'
  }
}

I tried dynamically injecting the components in the transform hook and even when I tried adding components into the fastifySwagger constructor this seems to not work.

fastify.register(fastifySwagger, {
    openapi: {
      components: {
		schema: {
		  foo: {
		    type: 'string'
		  }
		}
	}
});

This function does not seem to reference openapi components:

fastify-swagger/lib/util/resolve-schema-reference.js

Lines 3 to 18 in 36a543c

	function resolveSchemaReference (rawSchema, ref) {
	const resolvedReference = ref.resolve(rawSchema, { externalSchemas: [ref.definitions().definitions] })
	// Ref has format `#/definitions/id`
	const schemaId = resolvedReference?.$ref?.split('/', 3)[2]
	if (schemaId === undefined) {
	return undefined
	}
	return resolvedReference.definitions[schemaId]
	}
	module.exports = {
	resolveSchemaReference
	}

and the rest of the code's support for components seem fairly limited.

Additionally this line in particular:

fastify-swagger/lib/util/resolve-schema-reference.js

Line 7 in 36a543c

const schemaId = resolvedReference?.$ref?.split('/', 3)[2]

only returns schemas.

I might revisit this repo to add proper openapi component support and start incrementally adding components to the openapiObject construct but for now I want to unblock my users.

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[mcollina]

lgtm

[samchungy]

Hey @gurgunday would you mind merging and releasing a patch version for this package?

I would love to cut a new release of my package, pinning the safe version for my consumers. Please and thank you! 🙏

[mcollina]

lgtm