schema.response without a status code throws a cryptic error message

[evanshortiss]

Prerequisites

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

Fastify version

3.29

Plugin version

No response

Node.js version

16.x

Operating system

macOS

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

12.3.1

Description

The current response schema definition is:

schema: {
  response: {
    $STATUS_CODE: your_schema_here
  }
}

I accidentally typed the following:

schema: {
  response:  your_schema_here
}

This results in an error that is a little cryptic, in my opinion:

FastifyError [Error]: Failed building the serialization schema for GET: /meters, due to error schema is invalid: data.properties should be object

It seems like this mistake could be captured by fastify, and a better error message could be returned to the user? Obviously the best solution is to RTFM correctly, so I understand if this is deemed not worthwhile :)

Steps to Reproduce

Pass a schema directly to response, without specifying a status code:

app.route({
  url: '/',
  method: 'GET',
  schema: {
    response: {
      type: 'array'
    }
  },
  handler: (req, reply) => {
    reply.send([])
  }
})

Expected Behavior

An error message stating "response schemas should be nested under a response code, e.g { 200: { type: 'object' } }" or similar.

[mcollina]

Would you like to send a Pull Request to address this issue? Remember to add unit tests.

[evanshortiss]

@mcollina sure, I can look into it 👍