Fix autoload_once_paths when using Pathnames & ruby 1.9

Under ruby 1.9.2 -
  "/var/log".starts_with?(Pathname.new("/var"))  # => false

so setting config.autoload_once_paths with Pathnames would not work

activesupport/lib/active_support/dependencies.rb

@@ -421,7 +421,8 @@ module ActiveSupport #:nodoc:
     end
 
     def load_once_path?(path)
-      autoload_once_paths.any? { |base| path.starts_with? base }
+      # to_s works around a ruby1.9 issue where #starts_with?(Pathname) will always return false
+      autoload_once_paths.any? { |base| path.starts_with? base.to_s }
     end
 
     # Attempt to autoload the provided module name by searching for a directory

activesupport/test/dependencies_test.rb

@@ -520,6 +520,24 @@ class DependenciesTest < Test::Unit::TestCase
     ActiveSupport::Dependencies.autoload_once_paths = []
   end
 
+  def test_autoload_once_pathnames_do_not_add_to_autoloaded_constants
+    with_autoloading_fixtures do
+      pathnames = ActiveSupport::Dependencies.autoload_paths.collect{|p| Pathname.new(p)}
+      ActiveSupport::Dependencies.autoload_paths = pathnames
+      ActiveSupport::Dependencies.autoload_once_paths = pathnames
+
+      assert ! ActiveSupport::Dependencies.autoloaded?("ModuleFolder")
+      assert ! ActiveSupport::Dependencies.autoloaded?("ModuleFolder::NestedClass")
+      assert ! ActiveSupport::Dependencies.autoloaded?(ModuleFolder)
+
+      1 if ModuleFolder::NestedClass # 1 if to avoid warning
+      assert ! ActiveSupport::Dependencies.autoloaded?(ModuleFolder::NestedClass)
+    end
+  ensure
+    Object.class_eval { remove_const :ModuleFolder }
+    ActiveSupport::Dependencies.autoload_once_paths = []
+  end
+
   def test_application_should_special_case_application_controller
     with_autoloading_fixtures do
       require_dependency 'application'