Add config.to_prepare back and add tests for it.

Signed-off-by: NCarl Lerche <carllerche@mac.com>

railties/lib/rails/application/finisher.rb

@@ -15,6 +15,12 @@ module Finisher
         end
       end
 
+      initializer :add_to_prepare_blocks do
+        config.to_prepare_blocks.each do |block|
+          ActionDispatch::Callbacks.to_prepare(&block)
+        end
+      end
+
       initializer :add_builtin_route do |app|
         if Rails.env.development?
           app.routes_reloader.paths << File.join(RAILTIES_PATH, 'builtin', 'routes.rb')
@@ -25,7 +31,7 @@ module Finisher
         app
       end
 
-      # Fires the user-supplied after_initialize block (config#after_initialize)
+      # Fires the user-supplied after_initialize block (config.after_initialize)
       initializer :after_initialize do
         config.after_initialize_blocks.each do |block|
           block.call(self)

railties/lib/rails/configuration.rb

@@ -52,6 +52,14 @@ def after_initialize(&blk)
         after_initialize_blocks << blk if blk
       end
 
+      def to_prepare_blocks
+        @@to_prepare_blocks ||= []
+      end
+
+      def to_prepare(&blk)
+        to_prepare_blocks << blk if blk
+      end
+
       def respond_to?(name)
         super || name.to_s =~ config_key_regexp
       end

railties/test/application/configuration_test.rb

@@ -12,6 +12,10 @@ def copy_app
       FileUtils.cp_r(app_path, new_app)
     end
 
+    def app
+      @app ||= Rails.application
+    end
+
     def setup
       FileUtils.rm_rf(new_app) if File.directory?(new_app)
       build_app
@@ -132,5 +136,24 @@ def setup
         require "#{app_path}/config/application"
       end
     end
+
+    test "config.to_prepare is forwarded to ActionDispatch" do
+      $prepared = false
+
+      add_to_config <<-RUBY
+        config.to_prepare do
+          $prepared = true
+        end
+      RUBY
+
+      assert !$prepared
+
+      require "#{app_path}/config/environment"
+      require 'rack/test'
+      extend Rack::Test::Methods
+
+      get "/"
+      assert $prepared
+    end
   end
 end