1 files changed, 26 insertions, 16 deletions

diff --git a/actionmailer/lib/action_mailer/parameterized.rb b/actionmailer/lib/action_mailer/parameterized.rb
index a0a5db7427..3acacc1f14 100644
--- a/actionmailer/lib/action_mailer/parameterized.rb
+++ b/actionmailer/lib/action_mailer/parameterized.rb
@@ -71,7 +71,7 @@ module ActionMailer
   #       @project    = params[:project]
   #       @summarizer = ProjectInvitationSummarizer.new(@project.bucket)
   #
-  #        mail subject: "#{@inviter.name.familiar} added you to a project in Basecamp (#{@account.name})"
+  #       mail subject: "#{@inviter.name.familiar} added you to a project in Basecamp (#{@account.name})"
   #     end
   #
   #     def bulk_project_invitation
@@ -82,9 +82,6 @@ module ActionMailer
   #   end
   #
   #   InvitationsMailer.with(inviter: person_a, invitee: person_b).account_invitation.deliver_later
-  #
-  # That's a big improvement! It's also fully backwards compatible. So you can start to gradually transition
-  # mailers that stand to benefit the most from parameterization one by one and leave the others behind.
   module Parameterized
     extend ActiveSupport::Concern
 
@@ -92,33 +89,46 @@ module ActionMailer
       attr_accessor :params
     end
 
-    class_methods do
+    module ClassMethods
+      # Provide the parameters to the mailer in order to use them in the instance methods and callbacks.
+      #
+      #   InvitationsMailer.with(inviter: person_a, invitee: person_b).account_invitation.deliver_later
+      #
+      # See Parameterized documentation for full example.
       def with(params)
         ActionMailer::Parameterized::Mailer.new(self, params)
       end
     end
 
-    class Mailer
+    class Mailer # :nodoc:
       def initialize(mailer, params)
         @mailer, @params = mailer, params
       end
 
-      def method_missing(method_name, *args)
-        if @mailer.action_methods.include?(method_name.to_s)
-          ActionMailer::Parameterized::MessageDelivery.new(@mailer, method_name, *args).tap { |pmd| pmd.params = @params }
-        else
-          super
+      private
+        def method_missing(method_name, *args)
+          if @mailer.action_methods.include?(method_name.to_s)
+            ActionMailer::Parameterized::MessageDelivery.new(@mailer, method_name, @params, *args)
+          else
+            super
+          end
+        end
+
+        def respond_to_missing?(method, include_all = false)
+          @mailer.respond_to?(method, include_all)
         end
-      end
     end
 
-    class MessageDelivery < ActionMailer::MessageDelivery
-      attr_accessor :params
+    class MessageDelivery < ActionMailer::MessageDelivery # :nodoc:
+      def initialize(mailer_class, action, params, *args)
+        super(mailer_class, action, *args)
+        @params = params
+      end
 
       private
         def processed_mailer
           @processed_mailer ||= @mailer_class.new.tap do |mailer|
-            mailer.params = params
+            mailer.params = @params
             mailer.process @action, *@args
           end
         end
@@ -134,7 +144,7 @@ module ActionMailer
     end
 
     class DeliveryJob < ActionMailer::DeliveryJob # :nodoc:
-      def perform(mailer, mail_method, delivery_method, params, *args) #:nodoc:
+      def perform(mailer, mail_method, delivery_method, params, *args)
         mailer.constantize.with(params).public_send(mail_method, *args).send(delivery_method)
       end
     end