Overriding rewrite_asset_path also requires overriding asset_file_path

In ActionView::Helpers::AssetTagHelper, rewrite_asset_path has the following comment:

# Break out the asset path rewrite in case plugins wish to put the asset id
# someplace other than the query string.

Unfortunately, if you actually do this, CSS and JS caching break. The asset_file_path method assumes that it should strip off the querystring to get the real file path. So it's necessary to override asset_file_path to do the opposite of whatever you made rewrite_asset_path do.

At the least this should be mentioned in the rewrite_asset_path comment. It would be better to untangle the asset tagging code that is generating URLs to appear in tags from the caching code that needs real file paths.