STI with non-default inheritance_column set on the class breaks has_many assoc

Looks like the issue is here:
https://github.com/cerebris/jsonapi-resources/blob/v0.7.0/lib/jsonapi/resource_serializer.rb#L307

With a cursory glance, it looks like the STI attribute is hard-coded to 'type', though the with the problem I am seeing personally, it could be that or a polymorphic association (unlikely, but maybe both). Either way, the issue can be reproduced with the setup below.

Also, may not be the best idea to assume the model has an :id field, instead you should be reading type from the parent's inheritance_column attribute and its primary_key from it's primary_key attribute.

If I get a chance today, I will look into fixing this, but thought I would report it in case I am unable to get to it before I forget about it lol

Create a new rails app:

$ rvm use 2.1.2
$ rails --version 
=> Rails 4.1.14
$ rails new testtest
$ cd testtest/
$ rails g model ParentModel i_got_an_sti_once:string poly_rel_uid:string poly_rel_type:string
$ rails g model HasManyChildModel uid:string
$ rake db:migrate

Add jsonapi-resources

# Gemfile
...
gem 'jsonapi-resources'
...

Add your routes

#./config/routes.rb
Rails.application.routes.draw do
  jsonapi_resources :has_many_child_models, param: :uid
end

Add your controller

# ./app/controllers/has_many_child_controller.rb
class HasManyChildModelsController < ApplicationController
  include JSONAPI::ActsAsResourceController
end

Add your parent model

# ./app/models/parent_model.rb
class ParentModel < ActiveRecord::Base
  self.inheritance_column = 'i_got_an_sti_once' # That's not true :'(
end

Add your child model

# ./app/models/child_model.rb
class ChildModel < ParentModel
  belongs_to :poly_rel, polymorphic: true 
end

Add your model that has_many child models

# ./app/models/has_many_child_model.rb
class HasManyChildModel < ActiveRecord::Base
  # attributes: :uid
  has_many :child_models, as: :poly_rel, primary_key: :uid, foreign_key: :poly_rel_uid
end

Add your has_many_child_models resource

# ./app/resources/has_many_child_model_resource.rb
class HasManyChildModelResource < JSONAPI::Resource
  has_many :child_models, polymorphic: true, foreign_key_on: :related
end

Add your child_model resource

# ./app/resources/child_model_resource.rb
class ChildModelResource < JSONAPI::Resource
end

Now, start you server:

$ rails s -p 3001

And navigate to:

http://localhost:3001/has_many_child_models?include=child_models

To see the error:

{  
   "errors":[  
      {  
         "title":"Internal Server Error",
         "detail":"Internal Server Error",
         "id":null,
         "href":null,
         "code":500,
         "source":null,
         "links":null,
         "status":"500",
         "meta":{  
            "exception":"SQLite3::SQLException: no such column: type: SELECT type, \"parent_models\".\"id\" FROM \"parent_models\"  WHERE \"parent_models\".\"i_got_an_sti_once\" IN ('ChildModel') AND \"parent_models\".\"poly_rel_uid\" = ? AND \"parent_models\".\"poly_rel_type\" = ?",
            "backtrace":[  
               "/Users/***/.rvm/gems/ruby-2.1.2/gems/sqlite3-1.3.11/lib/sqlite3/database.rb:91:in `initialize'",
               "/Users/***/.rvm/gems/ruby-2.1.2/gems/sqlite3-1.3.11/lib/sqlite3/database.rb:91:in `new'",
               "/Users/***/.rvm/gems/ruby-2.1.2/gems/sqlite3-1.3.11/lib/sqlite3/database.rb:91:in `prepare'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.14/lib/active_record/connection_adapters/sqlite3_adapter.rb:311:in `block in exec_query'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.14/lib/active_record/connection_adapters/abstract_adapter.rb:378:in `block in log'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.14/lib/active_support/notifications/instrumenter.rb:20:in `instrument'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.14/lib/active_record/connection_adapters/abstract_adapter.rb:372:in `log'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.14/lib/active_record/connection_adapters/sqlite3_adapter.rb:298:in `exec_query'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.14/lib/active_record/connection_adapters/sqlite3_adapter.rb:510:in `select'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.14/lib/active_record/connection_adapters/abstract/database_statements.rb:24:in `select_all'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.14/lib/active_record/connection_adapters/abstract/query_cache.rb:68:in `block in select_all'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.14/lib/active_record/connection_adapters/abstract/query_cache.rb:83:in `cache_sql'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.14/lib/active_record/connection_adapters/abstract/query_cache.rb:68:in `select_all'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.14/lib/active_record/relation/calculations.rb:172:in `pluck'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.14/lib/active_record/associations/collection_proxy.rb:31:in `pluck'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:307:in `foreign_key_types_and_values'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:262:in `to_many_linkage'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:285:in `link_object_to_many'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:293:in `link_object'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:189:in `block in relationship_data'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:181:in `each'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:181:in `each_with_object'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:181:in `relationship_data'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:130:in `object_hash'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:102:in `block in process_primary'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:96:in `each'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:96:in `process_primary'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/resource_serializer.rb:39:in `serialize_to_hash'",
               "/Users/******/.rvm/gems/ruby-2.1.2/gems/jsonapi-resources-0.7.0/lib/jsonapi/response_document.rb:111:in `results_to_hash'",
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   ]
}

Commencez dans lib/jsonapi/resource_serializer.rb à la ligne 307 et reproduisez l’échec avec l’endpoint has_many_child_models et la configuration include=child_models décrite dans l’issue. Vérifiez comment le serializer obtient les valeurs STI et de primary key pour l’association, puis vérifiez que la requête se termine sans interroger la colonne type inexistante et respecte les inheritance_column et primary_key configurés.