Include application's helpers and router helpers by default, but include engine's ones for controllers inside isolated namespace

2 files changed, 14 insertions, 0 deletions

diff --git a/actionmailer/lib/action_mailer/railtie.rb b/actionmailer/lib/action_mailer/railtie.rb
index c888e51b93..26fe125fd8 100644
--- a/actionmailer/lib/action_mailer/railtie.rb
+++ b/actionmailer/lib/action_mailer/railtie.rb
@@ -1,5 +1,6 @@
 require "action_mailer"
 require "rails"
+require "action_mailer/railties/routes_helpers"
 
 module ActionMailer
   class Railtie < Rails::Railtie
@@ -20,6 +21,7 @@ module ActionMailer
       ActiveSupport.on_load(:action_mailer) do
         include app.routes.url_helpers
         include app.routes.mounted_helpers(:app)
+        extend ::ActionMailer::Railties::RoutesHelpers
         options.each { |k,v| send("#{k}=", v) }
       end
     end
diff --git a/actionmailer/lib/action_mailer/railties/routes_helpers.rb b/actionmailer/lib/action_mailer/railties/routes_helpers.rb
new file mode 100644
index 0000000000..3464ec38e2
--- /dev/null
+++ b/actionmailer/lib/action_mailer/railties/routes_helpers.rb
@@ -0,0 +1,12 @@
+module ActionMailer
+  module Railties
+    module RoutesHelpers
+      def inherited(klass)
+        super(klass)
+        if namespace = klass.parents.detect {|m| m.respond_to?(:_railtie) }
+          klass.send(:include, namespace._railtie.routes.url_helpers)
+        end
+      end
+    end
+  end
+end