idea {
    module {
        excludeDirs = [project.file('folderThatIsExcludedNow')] as Set
        iml {
            beforeMerged { it.excludeFolders.clear() }
            whenMerged   { it.jdkName = '1.33'   }
        }
    }
}
''')
        //then
        def iml = getFile([:], 'root.iml').text
        assert iml.contains('folderThatIsExcludedNow')
        assert !iml.contains('folderThatWasExcludedEarlier')