require_dependency should allow Pathname-like objects, not just String

activesupport/lib/active_support/dependencies.rb

@@ -198,9 +198,11 @@ module ActiveSupport #:nodoc:
         Dependencies.require_or_load(file_name)
       end
 
+      # Files required this way can be reloaded in development mode
       def require_dependency(file_name, message = "No such file to load -- %s")
+        file_name = file_name.to_path if file_name.respond_to?(:to_path)
         unless file_name.is_a?(String)
-          raise ArgumentError, "the file name must be a String -- you passed #{file_name.inspect}"
+          raise ArgumentError, "the file name must either be a String or implement #to_path -- you passed #{file_name.inspect}"
         end
 
         Dependencies.depend_on(file_name, message)

activesupport/test/dependencies_test.rb

@@ -35,6 +35,17 @@ class DependenciesTest < ActiveSupport::TestCase
     assert_equal expected.path, e.path
   end
 
+  def test_require_dependency_accepts_an_object_which_implements_to_path
+    o = Object.new
+    def o.to_path; 'dependencies/service_one'; end
+    assert_nothing_raised {
+      require_dependency o
+    }
+    assert defined?(ServiceOne)
+  ensure
+    remove_constants(:ServiceOne)
+  end
+
   def test_tracking_loaded_files
     require_dependency 'dependencies/service_one'
     require_dependency 'dependencies/service_two'