removes the obsolete require_association method from dependencies

This is an obsolete method from the very early days,
apparently it was used circa 2004 because STI support
was not smart enough. This method is not public
interface, and we are heading a major version, so
removal seems right.

activesupport/CHANGELOG.md

@@ -1,5 +1,7 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Remove obsolete and unused `require_association` method from dependencies. *fxn*
+
 *   Add `:instance_accessor` option for `config_accessor`.
 
         class User

activesupport/lib/active_support/dependencies.rb

@@ -168,8 +168,6 @@ module ActiveSupport #:nodoc:
         end
       end
 
-      # Use const_missing to autoload associations so we don't have to
-      # require_association when using single-table inheritance.
       def const_missing(const_name, nesting = nil)
         klass_name = name.presence || "Object"
 
@@ -220,11 +218,7 @@ module ActiveSupport #:nodoc:
           raise ArgumentError, "the file name must be a String -- you passed #{file_name.inspect}"
         end
 
-        Dependencies.depend_on(file_name, false, message)
-      end
-
-      def require_association(file_name)
-        Dependencies.associate_with(file_name)
+        Dependencies.depend_on(file_name, message)
       end
 
       def load_dependency(file)
@@ -306,20 +300,14 @@ module ActiveSupport #:nodoc:
       mechanism == :load
     end
 
-    def depend_on(file_name, swallow_load_errors = false, message = "No such file to load -- %s.rb")
+    def depend_on(file_name, message = "No such file to load -- %s.rb")
       path = search_for_file(file_name)
       require_or_load(path || file_name)
     rescue LoadError => load_error
-      unless swallow_load_errors
-        if file_name = load_error.message[/ -- (.*?)(\.rb)?$/, 1]
-          raise LoadError.new(message % file_name).copy_blame!(load_error)
-        end
-        raise
+      if file_name = load_error.message[/ -- (.*?)(\.rb)?$/, 1]
+        raise LoadError.new(message % file_name).copy_blame!(load_error)
       end
-    end
-
-    def associate_with(file_name)
-      depend_on(file_name, true)
+      raise
     end
 
     def clear

activesupport/test/dependencies_test.rb

@@ -60,10 +60,6 @@ class DependenciesTest < ActiveSupport::TestCase
     assert_raise(MissingSourceFile) { require_dependency("missing_service") }
   end
 
-  def test_missing_association_raises_nothing
-    assert_nothing_raised { require_association("missing_model") }
-  end
-
   def test_dependency_which_raises_exception_isnt_added_to_loaded_set
     with_loading do
       filename = 'dependencies/raises_exception'