Rails.root returns nil before app initialization, silently breaking some gems

While updating thinking-sphinx gem to work with rails 3.0, I've noticed that it got wrong paths for its configuration files, like absolute "/config/..", "/db/..." instead of relative "#{Rails.root}/config".

Problem is, in rails 2.x gems were required after Rails.root is initialized. And default rails 3.0 application generator uses Bundler, and auto-requires all gems before application initialization. That problem could be easily solved with "gem 'problem-gem', :require => false" in Gemfile, and separate "require 'problem-gem'" in initializer, but it's annoyingly hard to track such a bug.

I'm pretty sure many other rails dependent gems check for defined?(Rails) but do not check for Rails.root.nil?, and use it blindly in paths calculation

there's a method in module Rails:

    def root
      application && application.config.root
    end

it seems to me that it shouldn't just silently return "nil" before application initialization, but rather throw some exception with a helpful message. What do you think?

And what is a new standard method for rails dependent gem initialization? Should it go in custom config/initializers/...rb, or put int config/application.rb itself?

I'll make a patch if this is a way to go.