Remove unused responsibilities and add a few load definitions to engines

Since plugins were removed, we can clean up a few methods in engines.
We also use this opportunity to move `load_console`, `load_tasks` and
`load_runner` to Rails::Engine. This means that, if someone wants to
improve script/rails for engines to support console or runner commands,
part of the work is already done.

4 files changed, 140 insertions, 147 deletions

diff --git a/railties/lib/rails/application.rb b/railties/lib/rails/application.rb
index 1a993a25cb..d5ec2cbfd9 100644
--- a/railties/lib/rails/application.rb
+++ b/railties/lib/rails/application.rb
@@ -79,9 +79,11 @@ module Rails
       @routes_reloader  = nil
       @env_config       = nil
       @ordered_railties = nil
+      @railties         = nil
       @queue            = nil
     end
 
+    # Returns true if the application is initialized.
     def initialized?
       @initialized
     end
@@ -98,30 +100,6 @@ module Rails
       routes_reloader.reload!
     end
 
-    # Load the application and its railties tasks and invoke the registered hooks.
-    # Check <tt>Rails::Railtie.rake_tasks</tt> for more info.
-    def load_tasks(app=self)
-      initialize_tasks
-      super
-      self
-    end
-
-    # Load the application console and invoke the registered hooks.
-    # Check <tt>Rails::Railtie.console</tt> for more info.
-    def load_console(app=self)
-      initialize_console
-      super
-      self
-    end
-
-    # Load the application runner and invoke the registered hooks.
-    # Check <tt>Rails::Railtie.runner</tt> for more info.
-    def load_runner(app=self)
-      initialize_runner
-      super
-      self
-    end
-
     # Stores some of the Rails initial environment parameters which
     # will be used by middlewares and engines to configure themselves.
     def env_config
@@ -188,32 +166,9 @@ module Rails
       self
     end
 
-    # Returns the ordered railties for this application considering railties_order.
-    def ordered_railties #:nodoc:
-      @ordered_railties ||= begin
-        order = config.railties_order.map do |railtie|
-          if railtie == :main_app
-            self
-          elsif railtie.respond_to?(:instance)
-            railtie.instance
-          else
-            railtie
-          end
-        end
-
-        all = (railties - order)
-        all.push(self)   unless (all + order).include?(self)
-        order.push(:all) unless order.include?(:all)
-
-        index = order.index(:all)
-        order[index] = all
-        order.reverse.flatten
-      end
-    end
-
     def initializers #:nodoc:
       Bootstrap.initializers_for(self) +
-      super +
+      railties_initializers(super) +
       Finisher.initializers_for(self)
     end
 
@@ -246,6 +201,66 @@ module Rails
 
     alias :build_middleware_stack :app
 
+    def run_tasks_blocks(app) #:nodoc:
+      railties.each { |r| r.run_tasks_blocks(app) }
+      super
+      require "rails/tasks"
+      task :environment do
+        $rails_rake_task = true
+        require_environment!
+      end
+    end
+
+    def run_generators_blocks(app) #:nodoc:
+      railties.each { |r| r.run_generators_blocks(app) }
+      super
+    end
+
+    def run_runner_blocks(app) #:nodoc:
+      railties.each { |r| r.run_runner_blocks(app) }
+      super
+    end
+
+    def run_console_blocks(app) #:nodoc:
+      railties.each { |r| r.run_console_blocks(app) }
+      super
+    end
+
+    # Returns the ordered railties for this application considering railties_order.
+    def ordered_railties #:nodoc:
+      @ordered_railties ||= begin
+        order = config.railties_order.map do |railtie|
+          if railtie == :main_app
+            self
+          elsif railtie.respond_to?(:instance)
+            railtie.instance
+          else
+            railtie
+          end
+        end
+
+        all = (railties - order)
+        all.push(self)   unless (all + order).include?(self)
+        order.push(:all) unless order.include?(:all)
+
+        index = order.index(:all)
+        order[index] = all
+        order.reverse.flatten
+      end
+    end
+
+    def railties_initializers(current) #:nodoc:
+      initializers = []
+      ordered_railties.each do |r|
+        if r == self
+          initializers += current
+        else
+          initializers += r.initializers
+        end
+      end
+      initializers
+    end
+
     def reload_dependencies? #:nodoc:
       config.reload_classes_only_on_change != true || reloaders.map(&:updated?).any?
     end
@@ -305,25 +320,6 @@ module Rails
       end
     end
 
-    def initialize_tasks #:nodoc:
-      self.class.rake_tasks do
-        require "rails/tasks"
-        task :environment do
-          $rails_rake_task = true
-          require_environment!
-        end
-      end
-    end
-
-    def initialize_console #:nodoc:
-      require "pp"
-      require "rails/console/app"
-      require "rails/console/helpers"
-    end
-
-    def initialize_runner #:nodoc:
-    end
-
     def build_original_fullpath(env) #:nodoc:
       path_info    = env["PATH_INFO"]
       query_string = env["QUERY_STRING"]
diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
index 7db602279a..309d265477 100644
--- a/railties/lib/rails/engine.rb
+++ b/railties/lib/rails/engine.rb
@@ -338,26 +338,6 @@ module Rails
   class Engine < Railtie
     autoload :Configuration, "rails/engine/configuration"
 
-    def initialize
-      @_all_autoload_paths = nil
-      @_all_load_paths     = nil
-      @app                 = nil
-      @config              = nil
-      @env_config          = nil
-      @helpers             = nil
-      @railties            = nil
-      @routes              = nil
-      super
-    end
-
-    def load_generators(app=self)
-      initialize_generators
-      railties.each { |r| r.load_generators(app) }
-      Rails::Generators.configure!(app.config.generators)
-      super
-      self
-    end
-
     class << self
       attr_accessor :called_from, :isolated
       alias :isolated? :isolated
@@ -406,7 +386,7 @@ module Rails
             end
 
             unless mod.respond_to?(:railtie_routes_url_helpers)
-              define_method(:railtie_routes_url_helpers) { railtie.routes_url_helpers }
+              define_method(:railtie_routes_url_helpers) { railtie.routes.url_helpers }
             end
           end
         end
@@ -426,25 +406,54 @@ module Rails
     delegate :middleware, :root, :paths, :to => :config
     delegate :engine_name, :isolated?, :to => "self.class"
 
-    def load_tasks(app=self)
-      railties.each { |r| r.load_tasks(app) }
+    def initialize
+      @_all_autoload_paths = nil
+      @_all_load_paths     = nil
+      @app                 = nil
+      @config              = nil
+      @env_config          = nil
+      @helpers             = nil
+      @routes              = nil
       super
-      paths["lib/tasks"].existent.sort.each { |ext| load(ext) }
     end
 
+    # Load console and invoke the registered hooks.
+    # Check <tt>Rails::Railtie.console</tt> for more info.
     def load_console(app=self)
-      railties.each { |r| r.load_console(app) }
-      super
+      require "pp"
+      require "rails/console/app"
+      require "rails/console/helpers"
+      run_console_blocks(app)
+      self
     end
 
+    # Load Rails runner and invoke the registered hooks.
+    # Check <tt>Rails::Railtie.runner</tt> for more info.
     def load_runner(app=self)
-      railties.each { |r| r.load_runner(app) }
-      super
+      run_runner_blocks(app)
+      self
     end
 
-    def eager_load!
-      railties.each(&:eager_load!)
+    # Load Rake, railties tasks and invoke the registered hooks.
+    # Check <tt>Rails::Railtie.rake_tasks</tt> for more info.
+    def load_tasks(app=self)
+      require "rake"
+      run_tasks_blocks(app)
+      self
+    end
 
+    # Load rails generators and invoke the registered hooks.
+    # Check <tt>Rails::Railtie.generators</tt> for more info.
+    def load_generators(app=self)
+      require "rails/generators"
+      run_generators_blocks(app)
+      Rails::Generators.configure!(app.config.generators)
+      self
+    end
+
+    # Eager load the application by loading all ruby
+    # files inside eager_load paths.
+    def eager_load!
       config.eager_load_paths.each do |load_path|
         matcher = /\A#{Regexp.escape(load_path)}\/(.*)\.rb\Z/
         Dir.glob("#{load_path}/**/*.rb").sort.each do |file|
@@ -453,10 +462,7 @@ module Rails
       end
     end
 
-    def railties
-      @railties ||= []
-    end
-
+    # Returns a module with all the helpers defined for the engine.
     def helpers
       @helpers ||= begin
         helpers = Module.new
@@ -468,14 +474,12 @@ module Rails
       end
     end
 
+    # Returns all registered helpers paths.
     def helpers_paths
       paths["app/helpers"].existent
     end
 
-    def routes_url_helpers
-      routes.url_helpers
-    end
-
+    # Returns the underlying rack application for this engine.
     def app
       @app ||= begin
         config.middleware = config.middleware.merge_into(default_middleware_stack)
@@ -483,20 +487,26 @@ module Rails
       end
     end
 
+    # Returns the endpoint for this engine. If none is registered,
+    # defaults to an ActionDispatch::Routing::RouteSet.
     def endpoint
       self.class.endpoint || routes
     end
 
+    # Define the Rack API for this engine.
     def call(env)
       app.call(env.merge!(env_config))
     end
 
+    # Defines additional Rack env configuration that is added on each call.
     def env_config
       @env_config ||= {
         'action_dispatch.routes' => routes
       }
     end
 
+    # Defines the routes for this engine. If a block is given to
+    # routes, it is appended to the engine.
     def routes
       @routes ||= ActionDispatch::Routing::RouteSet.new.tap do |routes|
         routes.draw_paths.concat paths["config/routes"].paths
@@ -506,22 +516,7 @@ module Rails
       @routes
     end
 
-    def ordered_railties
-      railties + [self]
-    end
-
-    def initializers
-      initializers = []
-      ordered_railties.each do |r|
-        if r == self
-          initializers += super
-        else
-          initializers += r.initializers
-        end
-      end
-      initializers
-    end
-
+    # Define the configuration object for the engine.
     def config
       @config ||= Engine::Configuration.new(find_root_with_flag("lib"))
     end
@@ -626,7 +621,6 @@ module Rails
             else
               Rake::Task["app:railties:install:migrations"].invoke
             end
-
           end
         end
       end
@@ -634,19 +628,20 @@ module Rails
 
     protected
 
-    def initialize_generators
-      require "rails/generators"
+    def run_tasks_blocks(*) #:nodoc:
+      super
+      paths["lib/tasks"].existent.sort.each { |ext| load(ext) }
     end
 
-    def routes?
+    def routes? #:nodoc:
       @routes
     end
 
-    def has_migrations?
+    def has_migrations? #:nodoc:
       paths["db/migrate"].existent.any?
     end
 
-    def find_root_with_flag(flag, default=nil)
+    def find_root_with_flag(flag, default=nil) #:nodoc:
       root_path = self.class.called_from
 
       while root_path && File.directory?(root_path) && !File.exist?("#{root_path}/#{flag}")
@@ -660,19 +655,19 @@ module Rails
       Pathname.new File.realpath root
     end
 
-    def default_middleware_stack
+    def default_middleware_stack #:nodoc:
       ActionDispatch::MiddlewareStack.new
     end
 
-    def _all_autoload_once_paths
+    def _all_autoload_once_paths #:nodoc:
       config.autoload_once_paths
     end
 
-    def _all_autoload_paths
+    def _all_autoload_paths #:nodoc:
       @_all_autoload_paths ||= (config.autoload_paths + config.eager_load_paths + config.autoload_once_paths).uniq
     end
 
-    def _all_load_paths
+    def _all_load_paths #:nodoc:
       @_all_load_paths ||= (config.paths.load_paths + _all_autoload_paths).uniq
     end
   end
diff --git a/railties/lib/rails/railtie.rb b/railties/lib/rails/railtie.rb
index a06be59759..1cb99463cc 100644
--- a/railties/lib/rails/railtie.rb
+++ b/railties/lib/rails/railtie.rb
@@ -181,33 +181,35 @@ module Rails
     def eager_load!
     end
 
-    def load_console(app=self)
+    def railtie_namespace
+      @railtie_namespace ||= self.class.parents.detect { |n| n.respond_to?(:railtie_namespace) }
+    end
+
+    protected
+
+    def run_console_blocks(app) #:nodoc:
       self.class.console.each { |block| block.call(app) }
     end
 
-    def load_runner(app=self)
+    def run_generators_blocks(app) #:nodoc:
+      self.class.generators.each { |block| block.call(app) }
+    end
+
+    def run_runner_blocks(app) #:nodoc:
       self.class.runner.each { |block| block.call(app) }
     end
 
-    def load_tasks(app=self)
-      require 'rake'
+    def run_tasks_blocks(app) #:nodoc:
       extend Rake::DSL
-      self.class.rake_tasks.each { |block| self.instance_exec(app, &block) }
+      self.class.rake_tasks.each { |block| instance_exec(app, &block) }
 
-      # load also tasks from all superclasses
+      # Load also tasks from all superclasses
       klass = self.class.superclass
+
       while klass.respond_to?(:rake_tasks)
-        klass.rake_tasks.each { |t| self.instance_exec(app, &t) }
+        klass.rake_tasks.each { |t| instance_exec(app, &t) }
         klass = klass.superclass
       end
     end
-
-    def load_generators(app=self)
-      self.class.generators.each { |block| block.call(app) }
-    end
-
-    def railtie_namespace
-      @railtie_namespace ||= self.class.parents.detect { |n| n.respond_to?(:railtie_namespace) }
-    end
   end
 end
diff --git a/railties/test/railties/engine_test.rb b/railties/test/railties/engine_test.rb
index 52c7fae6c6..63814f7a04 100644
--- a/railties/test/railties/engine_test.rb
+++ b/railties/test/railties/engine_test.rb
@@ -1098,7 +1098,7 @@ YAML
       assert_equal "// App's bar js\n;", last_response.body.strip
 
       # ensure that railties are not added twice
-      railties = Rails.application.ordered_railties.map(&:class)
+      railties = Rails.application.send(:ordered_railties).map(&:class)
       assert_equal railties, railties.uniq
     end