2 files changed, 38 insertions, 15 deletions

diff --git a/railties/lib/rails/application/configuration.rb b/railties/lib/rails/application/configuration.rb
index f415a20833..285a63d4c6 100644
--- a/railties/lib/rails/application/configuration.rb
+++ b/railties/lib/rails/application/configuration.rb
@@ -16,7 +16,7 @@ module Rails
                     :railties_order, :relative_url_root, :secret_key_base, :secret_token,
                     :ssl_options, :public_file_server,
                     :session_options, :time_zone, :reload_classes_only_on_change,
-                    :beginning_of_week, :filter_redirect, :x
+                    :beginning_of_week, :filter_redirect, :x, :enable_dependency_loading
 
       attr_writer :log_level
       attr_reader :encoding, :api_only, :static_cache_control
@@ -34,8 +34,7 @@ module Rails
         @public_file_server.index_name   = "index"
         @force_ssl                       = false
         @ssl_options                     = {}
-        @session_store                   = :cookie_store
-        @session_options                 = {}
+        @session_store                   = nil
         @time_zone                       = "UTC"
         @beginning_of_week               = :monday
         @log_level                       = nil
@@ -54,6 +53,7 @@ module Rails
         @api_only                        = false
         @debug_exception_response_format = nil
         @x                               = Custom.new
+        @enable_dependency_loading       = false
       end
 
       def static_cache_control=(value)
@@ -164,29 +164,37 @@ module Rails
         self.generators.colorize_logging = val
       end
 
-      def session_store(*args)
-        if args.empty?
-          case @session_store
-          when :disabled
-            nil
-          when :active_record_store
+      def session_store(new_session_store = nil, **options)
+        if new_session_store
+          if new_session_store == :active_record_store
             begin
               ActionDispatch::Session::ActiveRecordStore
             rescue NameError
               raise "`ActiveRecord::SessionStore` is extracted out of Rails into a gem. " \
                 "Please add `activerecord-session_store` to your Gemfile to use it."
             end
+          end
+
+          @session_store = new_session_store
+          @session_options = options || {}
+        else
+          case @session_store
+          when :disabled
+            nil
+          when :active_record_store
+            ActionDispatch::Session::ActiveRecordStore
           when Symbol
             ActionDispatch::Session.const_get(@session_store.to_s.camelize)
           else
             @session_store
           end
-        else
-          @session_store = args.shift
-          @session_options = args.shift || {}
         end
       end
 
+      def session_store? #:nodoc:
+        @session_store
+      end
+
       def annotations
         SourceAnnotationExtractor::Annotation
       end
@@ -205,6 +213,10 @@ module Rails
             }
           end
         end
+
+        def respond_to_missing?(symbol, *)
+          true
+        end
       end
     end
   end
diff --git a/railties/lib/rails/application/finisher.rb b/railties/lib/rails/application/finisher.rb
index 0aed6c1351..64de10a5c7 100644
--- a/railties/lib/rails/application/finisher.rb
+++ b/railties/lib/rails/application/finisher.rb
@@ -21,15 +21,26 @@ module Rails
 
       initializer :add_builtin_route do |app|
         if Rails.env.development?
-          app.routes.append do
+          app.routes.prepend do
             get '/rails/info/properties' => "rails/info#properties", internal: true
             get '/rails/info/routes'     => "rails/info#routes", internal: true
             get '/rails/info'            => "rails/info#index", internal: true
+          end
+
+          app.routes.append do
             get '/'                      => "rails/welcome#index", internal: true
           end
         end
       end
 
+      # Setup default session store if not already set in config/application.rb
+      initializer :setup_default_session_store, before: :build_middleware_stack do |app|
+        unless app.config.session_store?
+          app_name = app.class.name ? app.railtie_name.chomp('_application') : ''
+          app.config.session_store :cookie_store, key: "_#{app_name}_session"
+        end
+      end
+
       initializer :build_middleware_stack do
         build_middleware_stack
       end
@@ -95,7 +106,7 @@ module Rails
 
         elsif config.allow_concurrency == :unsafe
           # Do nothing, even if we know this is dangerous. This is the
-          # historical behaviour for true.
+          # historical behavior for true.
 
         else
           # Default concurrency setting: enabled, but safe
@@ -173,7 +184,7 @@ module Rails
 
       # Disable dependency loading during request cycle
       initializer :disable_dependency_loading do
-        if config.eager_load && config.cache_classes
+        if config.eager_load && config.cache_classes && !config.enable_dependency_loading
           ActiveSupport::Dependencies.unhook!
         end
       end