Extending a model breaks one-to-many relationship

[navels]

We're running into issues around polymorphism upgrading our app to v3 and I think I've found a bug.

I took the one-to-many twiddle from this blog post and

• subclassed the author model with robot.js

Just that one thing, without actually creating any robots or robot books, etc., was enough to break the linkage of books back to authors:

{
  "authors": [
    {
      "name": "John Steinbeck",
      "bookIds": [
        "1",
        "2",
        "3"
      ],
      "id": "1"
    }
  ],
  "books": [
    {
      "title": "Of Mice and Men",
      "authorId": null,
      "id": "1"
    },
    {
      "title": "The Grapes of Wrath",
      "authorId": null,
      "id": "2"
    },
    {
      "title": "Travels with Charley",
      "authorId": null,
      "id": "3"
    }
  ],
  "robots": []
}

Here is my twiddle showing this behavior:

• https://ember-twiddle.com/b172b87eaf36a1c86042a10ea2c5a839

A workaround is to repeat the association on the derived model:

import Author from './author';
import { hasMany } from 'ember-cli-mirage';
export default Author.extend({
  books: hasMany()
});

or use this form to create books:

server.create('book', {
  author,
  title: 'Of Mice and Men'
});