class Gem::RequestSet

def tsort_each_child node # :nodoc:
  node.spec.dependencies.each do |dep|
    next if dep.type == :development and not @development
    match = @requests.find { |r|
      dep.match? r.spec.name, r.spec.version, @prerelease
    }
    unless match then
      next if dep.type == :development and @development_shallow
      next if @soft_missing
      raise Gem::DependencyError,
            "Unresolved dependency found during sorting - #{dep} (requested by #{node.spec.full_name})"
    end
    yield match
  end
end