NoMethodError: undefined method `root=' for ActiveModel::Serializer:Class

[agoodno]

In config/initializers/active_model_serializers.rb:

ActiveModel::Serializer.root = false
ActiveModel::ArraySerializer.root = false

Working Gemfile contains:

gem 'active_model_serializers', github: 'rails-api/active_model_serializers', ref: 'e185becd5d007da2f951d1f88c8872a2deb929e5'

Changed Gemfile to use HEAD:

gem 'active_model_serializers', github: 'rails-api/active_model_serializers'

Any ideas why I now get this error when running 'rake test'?

rake aborted!
NoMethodError: undefined method `root=' for ActiveModel::Serializer:Class
~/.rvm/gems/ruby-2.1.1@project1/gems/attr_encrypted-1.3.3/lib/attr_encrypted.rb:258:in `method_missing'
~/src/project1/config/initializers/active_model_serializers.rb:2:in `<top (required)>'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:241:in `load'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:241:in `block in load'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:232:in `load_dependency'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:241:in `load'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/engine.rb:648:in `block in load_config_initializer'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/notifications.rb:161:in `instrument'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/engine.rb:647:in `load_config_initializer'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/engine.rb:612:in `block (2 levels) in <class:Engine>'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/engine.rb:611:in `each'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/engine.rb:611:in `block in <class:Engine>'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/initializable.rb:30:in `instance_exec'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/initializable.rb:30:in `run'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/initializable.rb:55:in `block in run_initializers'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/initializable.rb:54:in `run_initializers'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/application.rb:300:in `initialize!'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/railtie.rb:194:in `public_send'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/railtie.rb:194:in `method_missing'
~/src/project1/config/environment.rb:5:in `<top (required)>'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:247:in `require'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:247:in `block in require'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:232:in `load_dependency'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:247:in `require'
~/src/project1/test/test_helper.rb:2:in `<top (required)>'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:247:in `require'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:247:in `block in require'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:232:in `load_dependency'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:247:in `require'
~/src/project1/test/models/account_task_test.rb:17:in `<top (required)>'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:247:in `require'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:247:in `block in require'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:232:in `load_dependency'
~/.rvm/gems/ruby-2.1.1@project1/gems/activesupport-4.1.5/lib/active_support/dependencies.rb:247:in `require'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/test_unit/sub_test_task.rb:114:in `block (3 levels) in define'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/test_unit/sub_test_task.rb:114:in `each'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/test_unit/sub_test_task.rb:114:in `block (2 levels) in define'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/test_unit/sub_test_task.rb:113:in `each'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/test_unit/sub_test_task.rb:113:in `block in define'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/test_unit/sub_test_task.rb:20:in `invoke_rake_task'
~/.rvm/gems/ruby-2.1.1@project1/gems/railties-4.1.5/lib/rails/test_unit/testing.rake:8:in `block in <top (required)>'
~/.rvm/gems/ruby-2.1.1@project1/bin/ruby_executable_hooks:15:in `eval'
~/.rvm/gems/ruby-2.1.1@project1/bin/ruby_executable_hooks:15:in `<main>'
Tasks: TOP => test:run => test:units
(See full trace by running task with --trace)

[steveklabnik]

Yes, root has not been implemented on master yet. You probably want 0.9-stable.

[steveklabnik]

Oh wait, that commit is on 0-9-stable.

I have no idea.

[agoodno]

lol, thanks for the quick response

[andrewle]

@agoodno Is this still an issue? I just tried this on a new Rails app (Rails 4.1.5) running on branch 0-9-stable of AMS and am not running into this error. If you get a chance, can you post an example app that repros the error?

[agoodno]

I'm not getting an error now but I've got tests failing which test the output JSON that the serializer generates. Most of my tests are passing so it's only a handful of tests failing with the new version. Looking into it a bit, it looks like it's not using the right serializer in some cases. It's using some default/generic serializer that I didn't create. Even when I specify the serializer to use, it ignores it in these cases.

original (previously used AccountUserSerializer based on naming standards)

render json: @account_user, status: :created

modified (to add specific serializer)

render json: @account_user, serializer: AccountUserSerializer, status: :created

The AR object before rendering

@account_user=#<AccountUser id: 1000984010, account_id: 1058068195, user_id: 980190962, is_active: true, created_at: "2014-11-20 14:23:26", updated_at: "2014-11-20 14:23:26", deactivated_at: nil, deactivated_by: nil, timeout_exempt: false>

The serializer

class AccountUserSerializer < ActiveModel::Serializer
  include Rails.application.routes.url_helpers

  attributes :id, :account_id, :account_name, :user_id, :is_active, :timeout_exempt

  has_one :user
  has_many :device_classes
  has_many :account_user_business_unit_roles
  has_many :account_user_location_roles

  def account_name
    object.account.name
  end
end

Final JSON output

json={"id"=>1000984010, "account_id"=>1058068195, "user_id"=>980190962, "is_active"=>true, "created_at"=>"2014-11-20T14:56:53.847Z", "updated_at"=>"2014-11-20T14:56:53.847Z", "deactivated_at"=>nil, "deactivated_by"=>nil, "timeout_exempt"=>false}

I believe it's not using my serializer because deactivated_at (and other attributes) are present but not specified in my serializer and account_name is not present but is specified. It's the account_name which my test is looking for and blows up because it's not there now. I'm not sure if this is related to the original error so I can open a new ticket if you think I should.

[JustinAiken]

Yes, root has not been implemented on master yet. You probably want 0.9-stable.

@steveklabnik

This still seems to be the case on 0.10.0rc1 - should ActiveModel::Serializer.root = true work on the .10 branch, or is that option deprecated?

[macfanatic]

Looks like this isn't supported yet on 0.10.0.rc2 either.

[joaomdmoura]

@macfanatic It is, but the way it's implemented is different 😄

The 0.10.x uses an adapter pattern. If you check the Adapters section on README you will see that we implemented 3 different Adapters, JSON, JSON API and Flatten JSON.

Some changes were made a couple weeks ago at the PR.

Now you can use the usual adapter configuration to determinate with you want to have a root or not:

# Without root, the default
ActiveModel::Serializer.config.adapter = :flatten_json

# With root
ActiveModel::Serializer.config.adapter = :json

# Following JSON API conventions
ActiveModel::Serializer.config.adapter = :json_api

[macfanatic]

Thanks @joaomdmoura I'll give that a try when I attempt to upgrade again. I had attempted to set the adapter to flatten_json and appeared that worked for my arrays, but was still getting object: {} root keys throughout any other items and just gave up.

[joaomdmoura]

@macfanatic sorry to hear that! Yeah, you should give it a try again! Way easier and stable 😄
In case you have some problem just show up at the IRC channel, post it on StackOverflow or on Github and let us know :)