Reorganized initializers a bit to enable better hooks for common cases without the need for Railtie. Specifically, the following hooks were added:

* before_configuration: this hook is run immediately after the Application class 
  comes into existence, but before the user has added any configuration. This is
  the appropriate place to set configuration for your plugin
* before_initialize: This is run after all of the user's configuration has completed,
  but before any initializers have begun (in other words, it runs right after
  config/environments/{development,production,test}.rb)
* after_initialize: This is run after all of the initializers have run. It is an
  appropriate place for forking in a preforking setup

Each of these hooks may be used via ActiveSupport.on_load(name) { }. In all these cases, the context inside the block will be the Application object. This means that for simple cases, you can use these hooks without needing to create a Railtie.

3 files changed, 7 insertions, 9 deletions

diff --git a/railties/lib/rails/application/bootstrap.rb b/railties/lib/rails/application/bootstrap.rb
index 022e1a91d8..e62eed8a87 100644
--- a/railties/lib/rails/application/bootstrap.rb
+++ b/railties/lib/rails/application/bootstrap.rb
@@ -10,7 +10,8 @@ module Rails
         require environment if environment
       end
 
-      initializer :load_all_active_support do
+      initializer :load_active_support do
+        require 'active_support/dependencies'
         require "active_support/all" unless config.active_support.bare
       end
 
@@ -18,7 +19,6 @@ module Rails
       # Used by Passenger to ensure everything's loaded before forking and
       # to avoid autoload race conditions in JRuby.
       initializer :preload_frameworks do
-        require 'active_support/dependencies'
         ActiveSupport::Autoload.eager_autoload! if config.preload_frameworks
       end
 
@@ -66,8 +66,8 @@ module Rails
         ActiveSupport::Dependencies.mechanism = config.cache_classes ? :require : :load
       end
 
-      initializer :bootstrap_load_path do
-        # This is just an initializer used as hook so all load paths are loaded together
+      initializer :bootstrap_hook do |app|
+        ActiveSupport.run_load_hooks(:before_initialize, app)
       end
     end
   end
diff --git a/railties/lib/rails/application/configuration.rb b/railties/lib/rails/application/configuration.rb
index 1ad77fdfec..cd77f1adaf 100644
--- a/railties/lib/rails/application/configuration.rb
+++ b/railties/lib/rails/application/configuration.rb
@@ -33,7 +33,7 @@ module Rails
       end
 
       def middleware
-        @middleware ||= default_middleware_stack
+        @middleware ||= app_middleware.merge_into(default_middleware_stack)
       end
 
       def metal_loader
diff --git a/railties/lib/rails/application/finisher.rb b/railties/lib/rails/application/finisher.rb
index 94507bb387..03bc270c81 100644
--- a/railties/lib/rails/application/finisher.rb
+++ b/railties/lib/rails/application/finisher.rb
@@ -35,10 +35,8 @@ module Rails
         app
       end
 
-      initializer :after_initialize do
-        config.after_initialize_blocks.each do |block|
-          block.call(self)
-        end
+      initializer :finisher_hook do |app|
+        ActiveSupport.run_load_hooks(:after_initialize, app)
       end
 
       # Disable dependency loading during request cycle