Side-loading objects with non-standard class names in EmberJS with Rails+active_model_serializers-Collection of common programming errors

I have a few models in Rails that look something like this:

class Issue < ActiveRecord::Base
  belongs_to :reporter, class_name: 'User'
  belongs_to :assignee, class_name: 'User'
  has_many :comments
end

class User < ActiveRecord::Base
end

class Comment < ActiveRecord::Base
end

with serializers like so:

class IssueSerializer < ActiveModel::Serializer
  attributes :id
  embed :ids, include: true

  has_one :reporter, :embed => :ids
  has_one :assignee, :embed => :ids
end

class UserSerializer < ActiveModel::Serializer
  attributes :id, :name
end

class CommentSerializer < ActiveModel::Serializer
  attributes :id, :body
end

This produces JSON that looks something like the following:

{
  "issues": [
    {
      "id": 6,
      "reporter_id": 1,
      "assignee_id": 2,
      "comment_ids": [
        3
      ]
    },
  ],
  "comments": [
    {
      "id": 3
      "body": "Great comment"
    }
  ],
  "reporters": [
    {
      "id": 1
      "name": "Ben Burton"
    }
  ],
  "assignees": [
    {
      "id": 2
      "name": "Jono Mallanyk"
    }
  ]
}

The problem is that the side-loaded reporters and assignees JSON objects aren’t recognized by Ember as User objects, and I see the following error:

Uncaught Error: assertion failed: Your server returned a hash with the key reporters but you have no mapping for it

I don’t want to remove

embed :ids, include: true

from my IssueSerializer, because then the comments wouldn’t be serialized.

There are a few potential ways to solve this that I’ve considered:

• If the embed method for ActiveModel::Serializer accepted a list of models in its include option, this could filter the JSON response to only include side-loaded comments.
• Ember data’s model could be configured to side load users from “users”, “reporters” and “assignees”… but as far as I can tell from the source it only appears to support one key for sideloadAs.
• Somehow ignore/disable side-loading errors for unknown keys (probably the least sane approach).

Is there another option I’m missing here? I think I may have to write a fix and submit a pull request to either rails-api/active_model_serializers, emberjs/data, or both.

EDIT: My temporary workaround for this is to change the IssueSerializer to only serialize the ids for reporter and assignee:

class IssueSerializer < ActiveModel::Serializer
  attributes :id, :reporter_id, :assignee_id
  embed :ids, include: true

  has_many :comments, :embed => :ids
end