We recently upgraded our project that was using subdomain_fu to rails 2.2 and the previous fix no longer works.

Turns out the solution is even easier in rails 2.2 than 2.1. Open up lib/subdomain_fu/routing_extensions.rb and put this bit of code at the very bottom:

ActionController::UrlRewriter::RESERVED_OPTIONS << :subdomain

Is this the correct way? Doesn’t seem to be since we’re modifying a “constant”, but it seems to work.