[PATCH] fix ActiveSupport::Dependencies removes properly loaded classes nested in autoloaded modules

I've discovered this under the following conditions:

• ApplicationController has helper :all call (it requires all helper files right away)
• some helpers are nested into Admin module, that module is autoloaded by directory name
• one of helper files contains either syntax error or requires missing file, so that either LoadError or SyntaxError gets thrown.

Here, application_controller.rb can't be loaded because one of it's dependencies fails. This situation is handled by new_constants_in and partially loaded constants are removed. Admin autoloaded module is considered as such and gets removed along with all its nested modules, so all Admin::* helpers get removed.

The problem is that although helpers where removed, their paths still exist in loaded set. So subsequent load of application_controller.rb (for rescue handling) throws another exception which can be misleading. It blames the first Admin::* helper with a message like "Expected app/helper/admin/some_helper.rb to define Admin::SomeHelper"

Please find proposed fix attached. It changes logic so that autoloaded modules are not removed on load failure recovery. I hope that makes sense as such modules are created by dependencies mechanism and should not have partially loaded state.

Also, condition in load_missing_constant is checking file_path with .rb extension against loaded set which holds paths without those. I think that does not cause any problems because require_or_load contains another check which is correct. I've changed that line, however.

The other test case and fix is also related to autoloaded modules handling. If some namespace spans across reloadable and load_once_paths, and module was created by a directory name from reloadable set, it gets removed on reload despite the fact that it holds classes from load_once_paths.

Hope that makes some sense. I wonder if these changes can produce any undesired side effects. All existing tests pass however.

Thanks
Serge