Get rid of config.preload_frameworks in favor of config.eager_load_namespaces

The new option allows any Ruby namespace to be registered and set
up for eager load. We are effectively exposing the structure existing
in Rails since v3.0 for all developers in order to make their applications
thread-safe and CoW friendly.

actionmailer/lib/action_mailer.rb

@@ -35,7 +35,10 @@
 module ActionMailer
   extend ::ActiveSupport::Autoload
 
-  autoload :Collector
+  eager_autoload do
+    autoload :Collector
+  end
+
   autoload :Base
   autoload :DeliveryMethods
   autoload :MailHelper

actionmailer/lib/action_mailer/railtie.rb

@@ -5,6 +5,7 @@
 module ActionMailer
   class Railtie < Rails::Railtie
     config.action_mailer = ActiveSupport::OrderedOptions.new
+    config.eager_load_namespaces << ActionMailer
 
     initializer "action_mailer.logger" do
       ActiveSupport.on_load(:action_mailer) { self.logger ||= Rails.logger }

actionpack/lib/action_controller.rb

@@ -48,6 +48,12 @@ module ActionController
   eager_autoload do
     autoload :RecordIdentifier
   end
+
+  def self.eager_load!
+    super
+    ActionController::Caching.eager_load!
+    HTML.eager_load!
+  end
 end
 
 # All of these simply register additional autoloads

actionpack/lib/action_controller/railtie.rb

@@ -9,6 +9,8 @@ module ActionController
   class Railtie < Rails::Railtie #:nodoc:
     config.action_controller = ActiveSupport::OrderedOptions.new
 
+    config.eager_load_namespaces << ActionController
+
     initializer "action_controller.assets_config", :group => :all do |app|
       app.config.action_controller.assets_dir ||= app.config.paths["public"].first
     end

actionpack/lib/action_dispatch.rb

@@ -38,9 +38,11 @@ module ActionDispatch
   class IllegalStateError < StandardError
   end
 
-  autoload_under 'http' do
-    autoload :Request
-    autoload :Response
+  eager_autoload do
+    autoload_under 'http' do
+      autoload :Request
+      autoload :Response
+    end
   end
 
   autoload_under 'middleware' do

actionpack/lib/action_dispatch/railtie.rb

@@ -25,6 +25,8 @@ class Railtie < Rails::Railtie
       'X-Content-Type-Options' => 'nosniff'
     }
 
+    config.eager_load_namespaces << ActionDispatch
+
     initializer "action_dispatch.configure" do |app|
       ActionDispatch::Http::URL.tld_length = app.config.action_dispatch.tld_length
       ActionDispatch::Request.ignore_accept_header = app.config.action_dispatch.ignore_accept_header

actionpack/lib/action_view.rb

@@ -38,7 +38,6 @@ module ActionView
     autoload :PathSet
     autoload :Template
 
-
     autoload_under "renderer" do
       autoload :Renderer
       autoload :AbstractRenderer
@@ -77,6 +76,11 @@ module ActionView
   autoload :TestCase
 
   ENCODING_FLAG = '#.*coding[:=]\s*(\S+)[ \t]*'
+
+  def self.eager_load!
+    super
+    ActionView::Template.eager_load!
+  end
 end
 
 require 'active_support/core_ext/string/output_safety'

actionpack/lib/action_view/railtie.rb

@@ -9,6 +9,8 @@ class Railtie < Rails::Railtie
     config.action_view.javascript_expansions = { :defaults => %w(jquery jquery_ujs) }
     config.action_view.embed_authenticity_token_in_remote_forms = false
 
+    config.eager_load_namespaces << ActionView
+
     initializer "action_view.embed_authenticity_token_in_remote_forms" do |app|
       ActiveSupport.on_load(:action_view) do
         ActionView::Helpers::FormTagHelper.embed_authenticity_token_in_remote_forms =

activemodel/lib/active_model.rb

@@ -34,7 +34,6 @@ module ActiveModel
   autoload :Conversion
   autoload :Dirty
   autoload :EachValidator, 'active_model/validator'
-  autoload :Errors
   autoload :Lint
   autoload :MassAssignmentSecurity
   autoload :Model
@@ -49,11 +48,22 @@ module ActiveModel
   autoload :Validations
   autoload :Validator
 
+  eager_autoload do
+    autoload :Errors
+  end
+
   module Serializers
     extend ActiveSupport::Autoload
 
-    autoload :JSON
-    autoload :Xml
+    eager_autoload do
+      autoload :JSON
+      autoload :Xml
+    end
+  end
+
+  def eager_load!
+    super
+    ActiveModel::Serializer.eager_load!
   end
 end
 

activemodel/lib/active_model/railtie.rb

@@ -1,2 +1,8 @@
 require "active_model"
-require "rails"
+require "rails"
+
+module ActiveModel
+  class Railtie < Rails::Railtie
+    config.eager_load_namespaces << ActiveModel
+  end
+end

activerecord/lib/active_record.rb

@@ -160,6 +160,15 @@ module Tasks
 
   autoload :TestCase
   autoload :TestFixtures, 'active_record/fixtures'
+
+  def self.eager_load!
+    super
+    ActiveRecord::Locking.eager_load!
+    ActiveRecord::Scoping.eager_load!
+    ActiveRecord::Associations.eager_load!
+    ActiveRecord::AttributeMethods.eager_load!
+    ActiveRecord::ConnectionAdapters.eager_load!
+  end
 end
 
 ActiveSupport.on_load(:active_record) do

activerecord/lib/active_record/railtie.rb

@@ -29,8 +29,11 @@ class Railtie < Rails::Railtie
       'ActiveRecord::RecordNotSaved'   => :unprocessable_entity
     )
 
+
     config.active_record.use_schema_cache_dump = true
 
+    config.eager_load_namespaces << ActiveRecord
+
     rake_tasks do
       require "active_record/base"
       load "active_record/railties/databases.rake"

activesupport/lib/active_support/railtie.rb

@@ -5,6 +5,8 @@ module ActiveSupport
   class Railtie < Rails::Railtie
     config.active_support = ActiveSupport::OrderedOptions.new
 
+    config.eager_load_namespaces << ActiveSupport
+
     initializer "active_support.deprecation_behavior" do |app|
       if deprecation = app.config.active_support.deprecation
         ActiveSupport::Deprecation.behavior = deprecation

guides/source/configuring.textile

@@ -107,8 +107,6 @@ end
 
 * +config.middleware+ allows you to configure the application's middleware. This is covered in depth in the "Configuring Middleware":#configuring-middleware section below.
 
-* +config.preload_frameworks+ enables or disables preloading all frameworks at startup. Enabled by +config.threadsafe!+. Defaults to +nil+, so is disabled.
-
 * +config.queue+ configures a different queue implementation for the application. Defaults to +Rails::Queueing::Queue+. Note that, if the default queue is changed, the default +queue_consumer+ is not going to be initialized, it is up to the new queue implementation to handle starting and shutting down its own consumer(s).
 
 * +config.queue_consumer+ configures a different consumer implementation for the default queue. Defaults to +Rails::Queueing::ThreadedConsumer+.
@@ -127,7 +125,7 @@ config.session_store :my_custom_store
 
 This custom store must be defined as +ActionDispatch::Session::MyCustomStore+. In addition to symbols, they can also be objects implementing a certain API, like +ActiveRecord::SessionStore+, in which case no special namespace is required.
 
-* +config.threadsafe!+ enables +cache_classes+, +dependency_loading+, +eager_load+ and +preload_frameworks+ to make the application threadsafe.
+* +config.threadsafe!+ enables +cache_classes+ and +eager_load+ to make the application threadsafe.
 
 WARNING: Threadsafe operation is incompatible with the normal workings of development mode Rails. In particular, automatic dependency loading and class reloading are automatically disabled when you call +config.threadsafe!+.
 
@@ -654,8 +652,6 @@ Serves as a placeholder so that +:load_environment_config+ can be defined to run
 
 *+load_active_support+* Requires +active_support/dependencies+ which sets up the basis for Active Support. Optionally requires +active_support/all+ if +config.active_support.bare+ is un-truthful, which is the default.
 
-*+preload_frameworks+* Loads all autoload dependencies of Rails automatically if +config.preload_frameworks+ is +true+ or "truthful". By default this configuration option is disabled. In Rails, when internal classes are referenced for the first time they are autoloaded. +:preload_frameworks+ loads all of this at once on initialization.
-
 *+initialize_logger+* Initializes the logger (an +ActiveSupport::BufferedLogger+ object) for the application and makes it accessible at +Rails.logger+, provided that no initializer inserted before this point has defined +Rails.logger+.
 
 *+initialize_cache+* If +Rails.cache+ isn't set yet, initializes the cache by referencing the value in +config.cache_store+ and stores the outcome as +Rails.cache+. If this object responds to the +middleware+ method, its middleware is inserted before +Rack::Runtime+ in the middleware stack.

railties/lib/rails/application.rb

@@ -83,13 +83,6 @@ def initialize
       @queue            = nil
     end
 
-    # Eager load all dependencies before eager loading
-    # the application.
-    def eager_load!
-      railties.each(&:eager_load!)
-      super
-    end
-
     # Returns true if the application is initialized.
     def initialized?
       @initialized

railties/lib/rails/application/bootstrap.rb

@@ -16,7 +16,7 @@ module Bootstrap
       initializer :set_eager_load, :group => :all do
         if config.eager_load.nil?
           warn <<-INFO
-config.eager_load is set to nil. Please update your config/environments file accordingly:
+config.eager_load is set to nil. Please update your config/environments/*.rb files accordingly:
 
   * development - set it to false
   * test - set it to false (unless you use a tool that preloads your test environment)
@@ -27,13 +27,6 @@ module Bootstrap
         end
       end
 
-      # Preload all frameworks specified by the Configuration#frameworks.
-      # Used by Passenger to ensure everything's loaded before forking and
-      # to avoid autoload race conditions in JRuby.
-      initializer :preload_frameworks, :group => :all do
-        ActiveSupport::Autoload.eager_autoload! if config.preload_frameworks
-      end
-
       # Initialize the logger early in the stack in case we need to log some deprecation.
       initializer :initialize_logger, :group => :all do
         Rails.logger ||= config.logger || begin

railties/lib/rails/application/configuration.rb

@@ -9,7 +9,7 @@ class Configuration < ::Rails::Engine::Configuration
                     :cache_classes, :cache_store, :consider_all_requests_local, :console,
                     :eager_load, :exceptions_app, :file_watcher, :filter_parameters,
                     :force_ssl, :helpers_paths, :logger, :log_formatter, :log_tags,
-                    :preload_frameworks, :railties_order, :relative_url_root, :secret_token,
+                    :railties_order, :relative_url_root, :secret_token,
                     :serve_static_assets, :ssl_options, :static_cache_control, :session_options,
                     :time_zone, :reload_classes_only_on_change,
                     :queue, :queue_consumer
@@ -95,7 +95,6 @@ def paths
       # after boot, and disables reloading code on every request, as these are
       # fundamentally incompatible with thread safety.
       def threadsafe!
-        @preload_frameworks = true
         @cache_classes = true
         @eager_load = true
         self

railties/lib/rails/application/finisher.rb

@@ -52,7 +52,7 @@ module Finisher
       initializer :eager_load! do
         if config.eager_load
           ActiveSupport.run_load_hooks(:before_eager_load, self)
-          eager_load!
+          config.eager_load_namespaces.each(&:eager_load!)
         end
       end
 

railties/lib/rails/engine.rb

@@ -339,11 +339,16 @@ class Engine < Railtie
 
     class << self
       attr_accessor :called_from, :isolated
+
       alias :isolated? :isolated
       alias :engine_name :railtie_name
 
+      delegate :eager_load!, to: :instance
+
       def inherited(base)
         unless base.abstract_railtie?
+          Rails::Railtie::Configuration.eager_load_namespaces << base
+
           base.called_from = begin
             # Remove the line number from backtraces making sure we don't leave anything behind
             call_stack = caller.map { |p| p.sub(/:\d+.*/, '') }

railties/lib/rails/railtie.rb

@@ -178,9 +178,6 @@ def config
       @config ||= Railtie::Configuration.new
     end
 
-    def eager_load!
-    end
-
     def railtie_namespace
       @railtie_namespace ||= self.class.parents.detect { |n| n.respond_to?(:railtie_namespace) }
     end

railties/lib/rails/railtie/configuration.rb

@@ -7,6 +7,16 @@ def initialize
         @@options ||= {}
       end
 
+      # Expose the eager_load_namespaces at "module" level for convenience.
+      def self.eager_load_namespaces #:nodoc:
+        @@eager_load_namespaces ||= []
+      end
+
+      # All namespaces that are eager loaded
+      def eager_load_namespaces
+        @@eager_load_namespaces ||= []
+      end
+
       # Add files that should be watched for change.
       def watchable_files
         @@watchable_files ||= []

railties/test/application/configuration_test.rb

@@ -176,22 +176,6 @@ def teardown
       end
     end
 
-    test "frameworks are not preloaded by default" do
-      require "#{app_path}/config/environment"
-
-      assert ActionController.autoload?(:Caching)
-    end
-
-    test "frameworks are preloaded with config.preload_frameworks is set" do
-      add_to_config <<-RUBY
-        config.preload_frameworks = true
-      RUBY
-
-      require "#{app_path}/config/environment"
-
-      assert !ActionView.autoload?(:AssetPaths)
-    end
-
     test "filter_parameters should be able to set via config.filter_parameters" do
       add_to_config <<-RUBY
         config.filter_parameters += [ :foo, 'bar', lambda { |key, value|

railties/test/application/rake_test.rb

@@ -75,7 +75,6 @@ def world
       RUBY
 
       output = Dir.chdir(app_path){ `rake do_nothing` }
-      puts output
       assert_match "Hello world", output
     end