Wonky fastify schema validation handling

fastify-registered-schemas.js

'use strict'
const fastify = require('fastify')
const fluent = require('fluent-json-schema')

const WhizBang = fluent
  .object()
  .additionalProperties(false)
  .id('whizbang')
  .title('WhizBang')
  .prop(
    'whiz'
  , fluent.string().required().minLength(1)
  )
  .prop(
    'bang'
  , fluent.string().required().minLength(1)
  )

const server = fastify({
  ajv: {
    customOptions: {
      allErrors: true
    }
  }
})

// Commenting this out will allow this to work as expected
// but openapi spec is missing schemas, and ref will not work
server.addSchema(WhizBang)

server
  .register(require('@fastify/swagger'), {
      routePrefix: '/oas'
    , exposeRoute: true
    , refResolver: {
        buildLocalReference(json, baseUri, fragment, i) {
          return json.$id || `my-fragment-${i}`
        }
      }
    , openapi: {
        openapi: '3.0.3'
      , info: {
          title: 'open api'
        , description: 'open api documentation'
        , version: 'v2'
        }
      , servers: [{
          url: 'http://localhost:3000'
        }]
      }
  })
  .register(async function(fastify) {
    fastify.post('/whizbang', {
      schema: {
        body: WhizBang.only('whiz')
      , response: {
          200: WhizBang
        }
      }
    , handler: async function(req, reply) {
        const body = req.body
        return {
          whiz: body.whiz,
          bang: 'foobar'
        }
      }
    })
  })

server
  .ready()
  .then(() => {
    return server.swagger()
  })
  .then(() => {
    return server.listen(3000)
  })
  .catch((error) => {
    process.nextTick(() => {
      throw error
    })
  })