class Bundler::Installer

def ensure_specs_are_compatible!
  system_ruby = Bundler::RubyVersion.system
  rubygems_version = Gem::Version.create(Gem::VERSION)
  @definition.specs.each do |spec|
    if required_ruby_version = spec.required_ruby_version
      unless required_ruby_version.satisfied_by?(system_ruby.gem_version)
        raise InstallError, "#{spec.full_name} requires ruby version #{required_ruby_version}, " \
          "which is incompatible with the current version, #{system_ruby}"
      end
    end
    next unless required_rubygems_version = spec.required_rubygems_version
    unless required_rubygems_version.satisfied_by?(rubygems_version)
      raise InstallError, "#{spec.full_name} requires rubygems version #{required_rubygems_version}, " \
        "which is incompatible with the current version, #{rubygems_version}"
    end
  end
end