# File lib/buildr/packaging/artifact_namespace.rb, line 511
        def unversioned_spec(spec)
          str = spec.to_s
          return nil if str =~ /^:+/
          ary = str.split(':')
          ary = ary[0...-1] if ary.size > 3
          if ary.size > 2
            ary.join(':')
          else
            new(spec).unversioned_spec
          end
        end