class Gem::Resolver::VendorSet

def add_vendor_gem(name, directory) # :nodoc:
  gemspec = File.join directory, "#{name}.gemspec"
  spec = Gem::Specification.load gemspec
  raise Gem::GemNotFoundException,
        "unable to find #{gemspec} for gem #{name}" unless spec
  spec.full_gem_path = File.expand_path directory
  @specs[spec.name]  = spec
  @directories[spec] = directory
  spec
end