RSpec load_missing_constant, expected X to define Y (and it does)

Question

When we run

bundle exec rake spec

it errors while trying to load the environment with the error:

...gems/activesupport-3.2.8/lib/active_support/dependencies.rb:503:in `load_missing_constant': Expected ...app/models/links/category.rb to define Links::Category (LoadError)

The file app/models/links/Category.rb does indeed define Links::Category. Even stranger is that error does not occur when running under guard and spork (the standard way we run tests):

bundle exec guard -i

Runs the test suite as expected without issue.

Spork is configured to run rspec, so I'm a bit confused about why running rake spec manually would cause this.

I've seen similar issues which seemed to be solved by looking at the autoload_paths, and checking if it was including lib and lib/** however ours isn't doing anything funky with autoload_paths that I can see. Our autoload_paths looks like this (defined in application.rb):

config.autoload_paths += %W(#{Rails.root}/app/src #{config.root}/app/api #{Rails.root}/app/products)

(We're using bundle exec rake spec in our CI server to run the tests rather than guard which we use on our development machines).

Does category.rb get loaded

Added puts 'Hey' at the top of category.rb, and puts 'Yo' at the bottom, and when running the specs the output incldues it:

DEPRECATION WARNING: ActiveAdmin::Dashboard is deprecated and will be removed in the next version
Hey
Yo
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:503:in `load_missing_constant': Expected /Users/shimms/Development/lexim/app/models/links/category.rb to define Links::Category (LoadError)

app/models/links/link.rb:

class Links::Link < ActiveRecord::Base
  self.table_name = 'links_category_links'
  attr_accessible :description, :name, :url, :category_id

  acts_as_paranoid

  belongs_to :category, :class_name => 'Links::Category'

  validates_presence_of :url
  validates_presence_of :name
end

app/models/links/category.rb:

class Links::Category < ActiveRecord::Base
  self.table_name = 'links_categories'
  attr_accessible :description, :name, :space_id

  acts_as_paranoid

  extend FriendlyId
  friendly_id :name, :use => :scoped, :scope => :space

  belongs_to :space
  belongs_to_space(:space)
  has_many :links, :class_name => 'Links::Link'

  validates_presence_of :name
end

spec_helper.rb

require File.expand_path('../../config/environment', __FILE__)
require 'rubygems'
require 'rails/all'
require 'rspec/rails'
require 'factory_girl'

system "#{Rails.root.to_s}/db/test.db"

ENV['RAILS_ENV'] ||= 'test'

load_schema = lambda {
  load "#{Rails.root.to_s}/db/schema.rb" # use db agnostic schema by default
                                         # ActiveRecord::Migrator.up('db/migrate') # use migrations
}
silence_stream(STDOUT, &load_schema)

Dir[Rails.root.join('spec/support/**/*.rb')].each { |f| require f }

RSpec.configure do |config|
  config.include FactoryGirl::Syntax::Methods

  config.mock_with :rspec
  config.fixture_path = "#{Rails.root}/spec/fixtures"
  config.use_transactional_fixtures = true

  ActiveSupport::Dependencies.clear
end

**Simplest category_spec.rb that causes error*:

require 'spec_helper'

describe Links::Category do
  pending "add some examples to (or delete) #{__FILE__}"
end

Rake execution:

➜  lexim git:(deveop) ✗ RAILS_ENV=test be rake spec --trace
** Invoke spec (first_time)
** Invoke db:test:prepare (first_time)
** Invoke db:abort_if_pending_migrations (first_time)
** Invoke environment (first_time)
** Execute environment
Agent is configured to send raw SQL to the service
Agent is configured to send raw SQL to the service
DEPRECATION WARNING: Passing :tag, :class and others to use is deprecated. Please invoke b.use :input, :wrap_with => {:class=>"span4"} instead. (called from block (2 levels) in <top (required)> at /Users/shimms/Development/lexim/config/initializers/simple_form.rb:47)
** Invoke db:load_config (first_time)
** Execute db:load_config
** Execute db:abort_if_pending_migrations
** Execute db:test:prepare
** Invoke db:test:load (first_time)
** Invoke db:test:purge (first_time)
** Invoke environment
** Invoke db:load_config
** Execute db:test:purge
** Execute db:test:load
** Invoke db:test:load_schema (first_time)
** Invoke db:test:purge
** Execute db:test:load_schema
** Invoke db:schema:load (first_time)
** Invoke environment
** Invoke db:load_config
** Execute db:schema:load
** Execute spec
/Users/shimms/.rvm/rubies/ruby-1.9.3-p125/bin/ruby -S rspec ./spec/product_features_spec.rb ./spec/controllers/lexim/logo_controller_spec.rb ./spec/mailers/enterprise_enquiry_mailer_spec.rb ./spec/mailers/new_account_mailer_spec.rb ./spec/mailers/user_mailer_spec.rb ./spec/models/account_boltons_spec.rb ./spec/models/account_spec.rb ./spec/models/account_status_spec.rb ./spec/models/address_spec.rb ./spec/models/admin/import_spec.rb ./spec/models/admin_user_spec.rb ./spec/models/assignment_materials_spec.rb ./spec/models/assignment_submission_rubric_selection_spec.rb ./spec/models/assignments/submission_files_spec.rb ./spec/models/assignments/submission_spec.rb ./spec/models/bolton_screenshot_spec.rb ./spec/models/bolton_spec.rb ./spec/models/bolton_status_spec.rb ./spec/models/calendar/entry_spec.rb ./spec/models/calendar/event_sharing_spec.rb ./spec/models/calendar_spec.rb ./spec/models/cancellation_reason_spec.rb ./spec/models/charge_spec.rb ./spec/models/client_application_spec.rb ./spec/models/common_cartridge/export_spec.rb ./spec/models/credit_card_spec.rb ./spec/models/discussions/reply_spec.rb ./spec/models/discussions/tag_spec.rb ./spec/models/education_domain_name_spec.rb ./spec/models/email_address_validation_spec.rb ./spec/models/gradebook/column_spec.rb ./spec/models/gradebook/value_spec.rb ./spec/models/gradebook_column_type_spec.rb ./spec/models/importer/user_spec.rb ./spec/models/invitation_spec.rb ./spec/models/invoice_spec.rb ./spec/models/links/category_spec.rb ./spec/models/links/link_spec.rb ./spec/models/mailing_list_spec.rb ./spec/models/material_item_spec.rb ./spec/models/materials/folder_spec.rb ./spec/models/materials/page_details_spec.rb ./spec/models/materials/page_spec.rb ./spec/models/materials/youtube_details_spec.rb ./spec/models/mobile_phone_country_carrier_spec.rb ./spec/models/mobile_phone_country_spec.rb ./spec/models/net_promoter_score_spec.rb ./spec/models/network_spec.rb ./spec/models/notification_channel_spec.rb ./spec/models/notification_event_spec.rb ./spec/models/notification_spec.rb ./spec/models/open_graph_object_authorization_spec.rb ./spec/models/plan_pool_spec.rb ./spec/models/plan_spec.rb ./spec/models/privacy_setting_spec.rb ./spec/models/product_bolton_spec.rb ./spec/models/product_spec.rb ./spec/models/quiz_spec.rb ./spec/models/quizzes/question_option_spec.rb ./spec/models/quizzes/question_spec.rb ./spec/models/quizzes/question_type_spec.rb ./spec/models/quizzes/submission_answer_option_spec.rb ./spec/models/quizzes/submission_answer_spec.rb ./spec/models/quizzes/submission_spec.rb ./spec/models/referrer_campaign_spec.rb ./spec/models/registration_spec.rb ./spec/models/rubric_spec.rb ./spec/models/rubrics/criterion_spec.rb ./spec/models/rubrics/descriptor_spec.rb ./spec/models/rubrics/level_spec.rb ./spec/models/sanitized_text_spec.rb ./spec/models/scheduled_mail_spec.rb ./spec/models/space_spec.rb ./spec/models/subscription_spec.rb ./spec/models/subscription_status_spec.rb ./spec/models/system_announcement_spec.rb ./spec/models/system_announcement_views_spec.rb ./spec/models/tip_spec.rb ./spec/models/tour_activity_spec.rb ./spec/models/unauthorized_access_spec.rb ./spec/models/unavailable_feature_request_spec.rb ./spec/models/user_activity_spec.rb ./spec/models/user_authentication_tokens_spec.rb ./spec/models/user_creation_type_spec.rb ./spec/models/user_notification_spec.rb ./spec/models/user_spec.rb ./spec/models/wall_post_likes_spec.rb ./spec/models/wallpost_spec.rb
Agent is configured to send raw SQL to the service
Agent is configured to send raw SQL to the service
DEPRECATION WARNING: Passing :tag, :class and others to use is deprecated. Please invoke b.use :input, :wrap_with => {:class=>"span4"} instead. (called from block (2 levels) in <top (required)> at /Users/shimms/Development/lexim/config/initializers/simple_form.rb:47)
DEPRECATION WARNING: ActiveAdmin::Dashboard is deprecated and will be removed in the next version
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:503:in `load_missing_constant': Expected /Users/shimms/Development/lexim/app/models/links/category.rb to define Links::Category (LoadError)
    from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:192:in `block in const_missing'
    from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:190:in `each'
from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:190:in `const_missing'
    from /Users/shimms/Development/lexim/spec/models/links/category_spec.rb:4:in `<top (required)>'
    from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:245:in `load'
from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:245:in `block in load'
    from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:236:in `load_dependency'
    from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:245:in `load'
from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rspec-core-2.10.1/lib/rspec/core/configuration.rb:746:in `block in load_spec_files'
    from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rspec-core-2.10.1/lib/rspec/core/configuration.rb:746:in `map'
    from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rspec-core-2.10.1/lib/rspec/core/configuration.rb:746:in `load_spec_files'
from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rspec-core-2.10.1/lib/rspec/core/command_line.rb:22:in `run'
    from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rspec-core-2.10.1/lib/rspec/core/runner.rb:69:in `run'
    from /Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rspec-core-2.10.1/lib/rspec/core/runner.rb:10:in `block in autorun'
rake aborted!
/Users/shimms/.rvm/rubies/ruby-1.9.3-p125/bin/ruby -S rspec ./spec/product_features_spec.rb ./spec/controllers/lexim/logo_controller_spec.rb ./spec/mailers/enterprise_enquiry_mailer_spec.rb ./spec/mailers/new_account_mailer_spec.rb ./spec/mailers/user_mailer_spec.rb ./spec/models/account_boltons_spec.rb ./spec/models/account_spec.rb ./spec/models/account_status_spec.rb ./spec/models/address_spec.rb ./spec/models/admin/import_spec.rb ./spec/models/admin_user_spec.rb ./spec/models/assignment_materials_spec.rb ./spec/models/assignment_submission_rubric_selection_spec.rb ./spec/models/assignments/submission_files_spec.rb ./spec/models/assignments/submission_spec.rb ./spec/models/bolton_screenshot_spec.rb ./spec/models/bolton_spec.rb ./spec/models/bolton_status_spec.rb ./spec/models/calendar/entry_spec.rb ./spec/models/calendar/event_sharing_spec.rb ./spec/models/calendar_spec.rb ./spec/models/cancellation_reason_spec.rb ./spec/models/charge_spec.rb ./spec/models/client_application_spec.rb ./spec/models/common_cartridge/export_spec.rb ./spec/models/credit_card_spec.rb ./spec/models/discussions/reply_spec.rb ./spec/models/discussions/tag_spec.rb ./spec/models/education_domain_name_spec.rb ./spec/models/email_address_validation_spec.rb ./spec/models/gradebook/column_spec.rb ./spec/models/gradebook/value_spec.rb ./spec/models/gradebook_column_type_spec.rb ./spec/models/importer/user_spec.rb ./spec/models/invitation_spec.rb ./spec/models/invoice_spec.rb ./spec/models/links/category_spec.rb ./spec/models/links/link_spec.rb ./spec/models/mailing_list_spec.rb ./spec/models/material_item_spec.rb ./spec/models/materials/folder_spec.rb ./spec/models/materials/page_details_spec.rb ./spec/models/materials/page_spec.rb ./spec/models/materials/youtube_details_spec.rb ./spec/models/mobile_phone_country_carrier_spec.rb ./spec/models/mobile_phone_country_spec.rb ./spec/models/net_promoter_score_spec.rb ./spec/models/network_spec.rb ./spec/models/notification_channel_spec.rb ./spec/models/notification_event_spec.rb ./spec/models/notification_spec.rb ./spec/models/open_graph_object_authorization_spec.rb ./spec/models/plan_pool_spec.rb ./spec/models/plan_spec.rb ./spec/models/privacy_setting_spec.rb ./spec/models/product_bolton_spec.rb ./spec/models/product_spec.rb ./spec/models/quiz_spec.rb ./spec/models/quizzes/question_option_spec.rb ./spec/models/quizzes/question_spec.rb ./spec/models/quizzes/question_type_spec.rb ./spec/models/quizzes/submission_answer_option_spec.rb ./spec/models/quizzes/submission_answer_spec.rb ./spec/models/quizzes/submission_spec.rb ./spec/models/referrer_campaign_spec.rb ./spec/models/registration_spec.rb ./spec/models/rubric_spec.rb ./spec/models/rubrics/criterion_spec.rb ./spec/models/rubrics/descriptor_spec.rb ./spec/models/rubrics/level_spec.rb ./spec/models/sanitized_text_spec.rb ./spec/models/scheduled_mail_spec.rb ./spec/models/space_spec.rb ./spec/models/subscription_spec.rb ./spec/models/subscription_status_spec.rb ./spec/models/system_announcement_spec.rb ./spec/models/system_announcement_views_spec.rb ./spec/models/tip_spec.rb ./spec/models/tour_activity_spec.rb ./spec/models/unauthorized_access_spec.rb ./spec/models/unavailable_feature_request_spec.rb ./spec/models/user_activity_spec.rb ./spec/models/user_authentication_tokens_spec.rb ./spec/models/user_creation_type_spec.rb ./spec/models/user_notification_spec.rb ./spec/models/user_spec.rb ./spec/models/wall_post_likes_spec.rb ./spec/models/wallpost_spec.rb failed
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rspec-core-2.10.1/lib/rspec/core/rake_task.rb:137:in `block (2 levels) in initialize'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/file_utils_ext.rb:60:in `verbose'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rspec-core-2.10.1/lib/rspec/core/rake_task.rb:127:in `block in initialize'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `block in execute'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/Users/shimms/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/bin/rake:23:in `load'
/Users/shimms/.rvm/gems/ruby-1.9.3-p125@lexim/bin/rake:23:in `<main>'
Tasks: TOP => spec

Answer 1

When your write Links::Category in your spec, Rails probably auto-loads the Links module and Links::Category class.

Apparently this strange error can happen if you are not properly defining the Links module. See the comments above for more details about how we debugged this.