refactor a bunch of controllers to make them EE modules

app/controllers/admin/applications_controller.rb

 class Admin::ApplicationsController < Admin::ApplicationController
   include OauthApplications
+  prepend EE::Admin::ApplicationsController
 
   before_action :set_application, only: [:show, :edit, :update, :destroy]
   before_action :load_scopes, only: [:new, :create, :edit, :update]
@@ -22,10 +23,7 @@ class Admin::ApplicationsController < Admin::ApplicationController
     @application = Doorkeeper::Application.new(application_params)
 
     if @application.save
-      log_audit_event
-
-      flash[:notice] = I18n.t(:notice, scope: [:doorkeeper, :flash, :applications, :create])
-      redirect_to admin_application_url(@application)
+      redirect_to_admin_page
     else
       render :new
     end
@@ -44,6 +42,13 @@ class Admin::ApplicationsController < Admin::ApplicationController
     redirect_to admin_applications_url, status: 302, notice: 'Application was successfully destroyed.'
   end
 
+  protected
+
+  def redirect_to_admin_page
+    flash[:notice] = I18n.t(:notice, scope: [:doorkeeper, :flash, :applications, :create])
+    redirect_to admin_application_url(@application)
+  end
+
   private
 
   def set_application

app/controllers/confirmations_controller.rb

 class ConfirmationsController < Devise::ConfirmationsController
-  include EE::Audit::Changes
+  prepend ::EE::ConfirmationsController
 
   def almost_there
     flash[:notice] = nil
@@ -14,12 +14,14 @@ class ConfirmationsController < Devise::ConfirmationsController
 
   def after_confirmation_path_for(resource_name, resource)
     if signed_in?(resource_name)
-      audit_changes(:email, as: 'email address', model: resource)
-
-      after_sign_in_path_for(resource)
+      after_sign_in(resource)
     else
       flash[:notice] += " Please sign in."
       new_session_path(resource_name)
     end
   end
+
+  def after_sign_in(resource)
+    after_sign_in_path_for(resource)
+  end
 end

app/controllers/oauth/applications_controller.rb

@@ -3,6 +3,7 @@ class Oauth::ApplicationsController < Doorkeeper::ApplicationsController
   include Gitlab::GonHelper
   include PageLayoutHelper
   include OauthApplications
+  prepend ::EE::Oauth::ApplicationsController
 
   before_action :verify_user_oauth_applications_enabled
   before_action :authenticate_user!
@@ -21,16 +22,20 @@ class Oauth::ApplicationsController < Doorkeeper::ApplicationsController
     @application.owner = current_user
 
     if @application.save
-      log_audit_event
-
-      flash[:notice] = I18n.t(:notice, scope: [:doorkeeper, :flash, :applications, :create])
-      redirect_to oauth_application_url(@application)
+      redirect_to_oauth_application_page
     else
       set_index_vars
       render :index
     end
   end
 
+  protected
+
+  def redirect_to_oauth_application_page
+    flash[:notice] = I18n.t(:notice, scope: [:doorkeeper, :flash, :applications, :create])
+    redirect_to oauth_application_url(@application)
+  end
+
   private
 
   def verify_user_oauth_applications_enabled

ee/app/controllers/ee/admin/applications_controller.rb

+module EE
+  module Admin
+    module ApplicationsController
+      protected
+
+      def redirect_to_admin_page
+        raise NotImplementedError unless defined?(super)
+
+        log_audit_event
+
+        super
+      end
+    end
+  end
+end

ee/app/controllers/ee/confirmations_controller.rb

+module EE
+  module ConfirmationsController
+    include EE::Audit::Changes
+
+    protected
+
+    def after_sign_in(resource)
+      raise NotImplementedError unless defined?(super)
+
+      audit_changes(:email, as: 'email address', model: resource)
+
+      super(resource)
+    end
+  end
+end

ee/app/controllers/ee/oauth/applications_controller.rb

+module EE
+  module Oauth
+    module ApplicationsController
+      protected
+
+      def redirect_to_oauth_application_page
+        raise NotImplementedError unless defined?(super)
+
+        log_audit_event
+
+        super
+      end
+    end
+  end
+end