Prepend the Prependable module to ActiveSupport::Concern

This is more robust on Ruby 2.1 where we would get the following error:

NoMethodError: super: no superclass method `included' for
EE::Namespace:Module
Signed-off-by: Rémy Coutable <remy@rymai.me>

app/models/ee/application_setting.rb

@@ -2,9 +2,9 @@ module EE
   # ApplicationSetting EE mixin
   #
   # This module is intended to encapsulate EE-specific model logic
-  # and be included in the `ApplicationSetting` model
+  # and be prepended in the `ApplicationSetting` model
   module ApplicationSetting
-    extend ::Prependable
+    extend ActiveSupport::Concern
 
     prepended do
       validates :shared_runners_minutes,

app/models/ee/namespace.rb

@@ -2,9 +2,9 @@ module EE
   # Namespace EE mixin
   #
   # This module is intended to encapsulate EE-specific model logic
-  # and be included in the `Namespace` model
+  # and be prepended in the `Namespace` model
   module Namespace
-    extend ::Prependable
+    extend ActiveSupport::Concern
 
     prepended do
       has_one :namespace_statistics, dependent: :destroy

app/models/ee/project.rb

@@ -2,9 +2,9 @@ module EE
   # Project EE mixin
   #
   # This module is intended to encapsulate EE-specific model logic
-  # and be included in the `Project` model
+  # and be prepended in the `Project` model
   module Project
-    extend ::Prependable
+    extend ActiveSupport::Concern
 
     prepended do
       scope :with_shared_runners_limit_enabled, -> { with_shared_runners.non_public_only }

app/services/ee/ci/register_build_service.rb

@@ -5,7 +5,7 @@ module EE
     # This module is intended to encapsulate EE-specific service logic
     # and be included in the `RegisterBuildService` service
     module RegisterBuildService
-      extend ::Prependable
+      extend ActiveSupport::Concern
 
       def builds_for_shared_runner
         return super unless shared_runner_build_limits_feature_enabled?

lib/prependable.rb → config/initializers/as_concern.rb

 # This module is based on: https://gist.github.com/bcardarella/5735987
 
 module Prependable
-  include ActiveSupport::Concern
-
-  def self.extended(base) #:nodoc:
-    base.instance_variable_set(:@_dependencies, [])
-  end
-
   def prepend_features(base)
     if base.instance_variable_defined?(:@_dependencies)
       base.instance_variable_get(:@_dependencies) << self
@@ -14,11 +8,17 @@ module Prependable
     else
       return false if base < self
       super
-      base.singleton_class.send(:prepend, const_get('ClassMethods'))  if const_defined?(:ClassMethods)
-      @_dependencies.each { |dep| base.send(:include, dep) }
+      base.singleton_class.send(:prepend, const_get('ClassMethods')) if const_defined?(:ClassMethods)
+      @_dependencies.each { |dep| base.send(:prepend, dep) }
       base.class_eval(&@_included_block) if instance_variable_defined?(:@_included_block)
     end
   end
+end
+
+module ActiveSupport
+  module Concern
+    prepend Prependable
 
-  alias_method :prepended, :included
+    alias_method :prepended, :included
+  end
 end

spec/lib/prependable_spec.rb

@@ -24,7 +24,7 @@ describe Prependable do
   end
 
   module Foo
-    extend Prependable
+    extend ActiveSupport::Concern
 
     prepended do
       def self.class_value