1 files changed, 24 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/dependency_module.rb b/activesupport/lib/active_support/dependency_module.rb
new file mode 100644
index 0000000000..0e1cc67b53
--- /dev/null
+++ b/activesupport/lib/active_support/dependency_module.rb
@@ -0,0 +1,24 @@
+module ActiveSupport
+  module DependencyModule
+    def setup(&blk)
+      @_setup_block = blk
+    end
+
+    def append_features(base)
+      return if base < self
+      (@_dependencies ||= []).each { |dep| base.send(:include, dep) }
+      super
+    end
+
+    def included(base)
+      base.extend const_get("ClassMethods") if const_defined?("ClassMethods")
+      base.class_eval(&@_setup_block) if instance_variable_defined?("@_setup_block")
+    end
+
+    def depends_on(mod)
+      return if self < mod
+      @_dependencies ||= []
+      @_dependencies << mod
+    end
+  end
+end