def require path
    if Gem.unresolved_deps.empty? then
      gem_original_require path
    else
      spec = Gem::Specification.find { |s|
        s.activated? and s.contains_requirable_file? path
      }

      unless spec then
        found_specs = Gem::Specification.find_in_unresolved path
        unless found_specs.empty? then
          found_specs = [found_specs.last]
        else
          found_specs = Gem::Specification.find_in_unresolved_tree path
        end

        found_specs.each do |found_spec|
          found_spec.activate
        end
      end

      return gem_original_require path
    end
  rescue LoadError => load_error
    if load_error.message.start_with?("Could not find") or
        (load_error.message.end_with?(path) and Gem.try_activate(path)) then
      return gem_original_require(path)
    end

    raise load_error
  end
#
When RubyGems is required, Kernel#require is replaced with our own which
is capable of loading gems on demand.

When you call <tt>require 'x'</tt>, this is what happens:
* If the file can be loaded from the existing Ruby loadpath, it
is.
* Otherwise, installed gems are searched for a file that matches.
If it's found in gem 'y', that gem is activated (added to the
loadpath).

The normal <tt>require</tt> functionality of returning false if
that file has already been loaded is preserved.