conf1.extendsFrom(conf2)
        conf2.extendsFrom(configuration)

        then:
        thrown InvalidUserDataException
    }

    def "reports cycle introduced by setExtends"() {
        def configuration = conf()
        def otherConf = conf("other")
        configuration.extendsFrom(otherConf)

        when:
        otherConf.setExtendsFrom([configuration])

        then: