A few changes were done in this commit:

* Added :autoload to engines path API and redefine usage to be in sync with 6f83a5036d8a9c3f8ed7;
* Do not autoload code in *lib* for applications (now you need to explicitly require them). This makes an application behave closer to an engine (code in lib is still autoloaded for plugins);
* Always autoload code in app/ for engines and plugins. This makes engines behave closer to an application and should allow us to get rid of the unloadable hack required when controllers inside engines inherit from ApplicationController;

6 files changed, 56 insertions, 47 deletions

diff --git a/railties/lib/rails/application.rb b/railties/lib/rails/application.rb
index aabe86715c..4a7ed2d028 100644
--- a/railties/lib/rails/application.rb
+++ b/railties/lib/rails/application.rb
@@ -28,7 +28,7 @@ module Rails
   # Besides providing the same configuration as Rails::Engine and Rails::Railtie,
   # the application object has several specific configurations, for example
   # "allow_concurrency", "cache_classes", "consider_all_requests_local", "filter_parameters",
-  # "logger", "reload_engines", "reload_plugins" and so forth.
+  # "logger", "reload_plugins" and so forth.
   #
   # Check Rails::Application::Configuration to see them all.
   #
@@ -217,10 +217,5 @@ module Rails
     def initialize_generators
       require "rails/generators"
     end
-
-    # Application is always reloadable when config.cache_classes is false.
-    def reloadable?(app)
-      true
-    end
   end
 end
diff --git a/railties/lib/rails/application/configuration.rb b/railties/lib/rails/application/configuration.rb
index e3165b2d4c..465851c0e6 100644
--- a/railties/lib/rails/application/configuration.rb
+++ b/railties/lib/rails/application/configuration.rb
@@ -10,7 +10,7 @@ module Rails
       attr_accessor :allow_concurrency, :cache_classes, :cache_store,
                     :encoding, :consider_all_requests_local, :dependency_loading,
                     :filter_parameters,  :log_level, :logger, :middleware,
-                    :plugins, :preload_frameworks, :reload_engines, :reload_plugins,
+                    :plugins, :preload_frameworks, :reload_plugins,
                     :secret_token, :serve_static_assets, :session_options,
                     :time_zone, :whiny_nils
 
@@ -59,7 +59,7 @@ module Rails
           if File.exists?("#{root}/test/mocks/#{Rails.env}")
             ActiveSupport::Deprecation.warn "\"Rails.root/test/mocks/#{Rails.env}\" won't be added " <<
               "automatically to load paths anymore in future releases"
-            paths.mocks_path  "test/mocks", :load_path => true, :glob => Rails.env
+            paths.mocks_path  "test/mocks", :autoload => true, :glob => Rails.env
           end
 
           paths
diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
index 0a3f21fb1b..ee3e3ba040 100644
--- a/railties/lib/rails/engine.rb
+++ b/railties/lib/rails/engine.rb
@@ -142,7 +142,7 @@ module Rails
 
     # Add configured load paths to ruby load paths and remove duplicates.
     initializer :set_load_path, :before => :bootstrap_hook do
-      config.autoload_paths.reverse_each do |path|
+      _all_load_paths.reverse_each do |path|
         $LOAD_PATH.unshift(path) if File.directory?(path)
       end
       $LOAD_PATH.uniq!
@@ -154,16 +154,12 @@ module Rails
     # This needs to be an initializer, since it needs to run once
     # per engine and get the engine as a block parameter
     initializer :set_autoload_paths, :before => :bootstrap_hook do |app|
-      ActiveSupport::Dependencies.autoload_paths.unshift(*config.autoload_paths)
-
-      if reloadable?(app)
-        ActiveSupport::Dependencies.autoload_once_paths.unshift(*config.autoload_once_paths)
-      else
-        ActiveSupport::Dependencies.autoload_once_paths.unshift(*config.autoload_paths)
-      end
+      ActiveSupport::Dependencies.autoload_paths.unshift(*_all_autoload_paths)
+      ActiveSupport::Dependencies.autoload_once_paths.unshift(*config.autoload_once_paths)
 
       # Freeze so future modifications will fail rather than do nothing mysteriously
       config.autoload_paths.freeze
+      config.eager_load_paths.freeze
       config.autoload_once_paths.freeze
     end
 
@@ -195,7 +191,6 @@ module Rails
       ActiveSupport.on_load(:action_controller) do
         prepend_view_path(views)
       end
-
       ActiveSupport.on_load(:action_mailer) do
         prepend_view_path(views)
       end
@@ -214,8 +209,12 @@ module Rails
 
   protected
 
-    def reloadable?(app)
-      app.config.reload_engines
+    def _all_autoload_paths
+      @_all_autoload_paths ||= (config.autoload_paths + config.eager_load_paths + config.autoload_once_paths).uniq
+    end
+
+    def _all_load_paths
+      @_all_load_paths ||= (config.paths.load_paths + _all_autoload_paths).uniq
     end
   end
 end
diff --git a/railties/lib/rails/engine/configuration.rb b/railties/lib/rails/engine/configuration.rb
index 4e27180f1e..2f465670cf 100644
--- a/railties/lib/rails/engine/configuration.rb
+++ b/railties/lib/rails/engine/configuration.rb
@@ -42,11 +42,11 @@ module Rails
       end
 
       def autoload_once_paths
-        @autoload_once_paths ||= paths.load_once
+        @autoload_once_paths ||= paths.autoload_once
       end
 
       def autoload_paths
-        @autoload_paths ||= paths.load_paths
+        @autoload_paths ||= paths.autoload_paths
       end
     end
   end
diff --git a/railties/lib/rails/paths.rb b/railties/lib/rails/paths.rb
index 1c9e308631..7a65188a9a 100644
--- a/railties/lib/rails/paths.rb
+++ b/railties/lib/rails/paths.rb
@@ -25,9 +25,7 @@ module Rails
 
       def initialize(path)
         raise if path.is_a?(Array)
-
         @children = {}
-
         @path = path
         @root = self
         @all_paths = []
@@ -38,14 +36,18 @@ module Rails
         @all_paths
       end
 
-      def load_once
-        filter_by(:load_once?)
+      def autoload_once
+        filter_by(:autoload_once?)
       end
 
       def eager_load
         filter_by(:eager_load?)
       end
 
+      def autoload_paths
+        filter_by(:autoload?)
+      end
+
       def load_paths
         filter_by(:load_path?)
       end
@@ -61,15 +63,17 @@ module Rails
     protected
 
       def filter_by(constraint)
-        all_paths.map do |path|
+        all = []
+        all_paths.each do |path|
           if path.send(constraint)
             paths  = path.paths
             paths -= path.children.values.map { |p| p.send(constraint) ? [] : p.paths }.flatten
-            paths
-          else
-            []
+            all.concat(paths)
           end
-        end.flatten.uniq.select { |p| File.exists?(p) }
+        end
+        all.uniq!
+        all.reject! { |p| !File.exists?(p) }
+        all
       end
     end
 
@@ -80,15 +84,16 @@ module Rails
       attr_accessor :glob
 
       def initialize(root, *paths)
-        @options  = paths.last.is_a?(::Hash) ? paths.pop : {}
+        options   = paths.last.is_a?(::Hash) ? paths.pop : {}
         @children = {}
         @root     = root
         @paths    = paths.flatten
-        @glob     = @options.delete(:glob)
+        @glob     = options[:glob]
 
-        @load_once  = @options[:load_once]
-        @eager_load = @options[:eager_load]
-        @load_path  = @options[:load_path] || @eager_load || @load_once
+        autoload_once! if options[:autoload_once]
+        eager_load!    if options[:eager_load]
+        autoload!      if options[:autoload]
+        load_path!     if options[:load_path]
 
         @root.all_paths << self
       end
@@ -111,24 +116,30 @@ module Rails
         @paths.concat paths
       end
 
-      def load_once!
-        @load_once = true
-        @load_path = true
+      def autoload_once!
+        @autoload_once = true
       end
 
-      def load_once?
-        @load_once
+      def autoload_once?
+        @autoload_once
       end
 
       def eager_load!
         @eager_load = true
-        @load_path  = true
       end
 
       def eager_load?
         @eager_load
       end
 
+      def autoload!
+        @autoload = true
+      end
+
+      def autoload?
+        @autoload
+      end
+
       def load_path!
         @load_path = true
       end
diff --git a/railties/lib/rails/plugin.rb b/railties/lib/rails/plugin.rb
index fcdd099135..be229cc9a2 100644
--- a/railties/lib/rails/plugin.rb
+++ b/railties/lib/rails/plugin.rb
@@ -61,6 +61,16 @@ module Rails
       @config ||= Engine::Configuration.new
     end
 
+    initializer :handle_lib_autoload, :before => :set_load_path do |app|
+      paths = if app.config.reload_plugins
+        config.autoload_paths
+      else
+        config.autoload_once_paths
+      end
+
+      paths.concat config.paths.lib.to_a
+    end
+
     initializer :load_init_rb, :before => :load_config_initializers do |app|
       files = %w(rails/init.rb init.rb).map { |path| File.expand_path path, root }
       if initrb = files.find { |path| File.file? path }
@@ -77,11 +87,5 @@ module Rails
         raise "\"#{name}\" is a Railtie/Engine and cannot be installed as plugin"
       end
     end
-
-  protected
-
-    def reloadable?(app)
-      app.config.reload_plugins
-    end
   end
 end