Unable to render this definition The provided definition does not specify a valid version field.

[Yacj]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Fastify version

5.2.0

Plugin version

5.2.0

Node.js version

v22.11.0

Operating system

Windows

Operating system version (i.e. 20.04, 11.3, 10)

win10

Description

When running the project and accessing the Swagger route, for example, http://127.0.0.1:3000/docs, the Swagger page reported this error.

Unable to render this definition
The provided definition does not specify a valid version field.

Please indicate a valid Swagger or OpenAPI version field. Supported version fields are swagger: "2.0" and those that match openapi: 3.x.y (for example, openapi: 3.1.0).

const path = require('node:path')
const AutoLoad = require('@fastify/autoload')
const cors = require('@fastify/cors')
const responseHandler = require('./middleware/resHandler.js')

const options= {}
module.exports = async function (fastify, opts) {
  await fastify.register(require('@fastify/swagger'),{
    openapi: {
      info: {
        title: 'Test swagger',
        description: 'Testing the Fastify swagger API',
        version: '0.1.0'
      },
      externalDocs: {
        url: 'https://swagger.io',
        description: 'Find more info here'
      }
    },
  })

 await fastify.register(require('@fastify/swagger-ui'), {
    routePrefix: '/docs',
    uiConfig: {
      docExpansion: 'full',
      deepLinking: false
    }
  })

  await responseHandler(fastify)
  fastify.register(cors, {
    origin: '*',
    methods: ['GET', 'PUT', 'POST', 'DELETE', 'OPTIONS']
  })

  fastify.register(AutoLoad, {
    dir: path.join(__dirname, 'plugins'),
    options: Object.assign({}, opts)
  })

  fastify.register(AutoLoad, {
    dir: path.join(__dirname, 'routes'),
    options: Object.assign({}, opts)
  })

  fastify.register(require('./plugins/env'))
}

module.exports.options = options

Link to code that reproduces the bug

No response

Expected Behavior

No response