@PathSensitive(PathSensitivity.RELATIVE)
    FileTree getSource() {
        return super.getSource()
    }

    @PathSensitive(PathSensitivity.RELATIVE)
    @InputDirectory
    abstract DirectoryProperty getStylesheetDirectory();

    @PathSensitive(PathSensitivity.RELATIVE)
    @InputFiles
    abstract ConfigurableFileCollection getDocbookStylesheets()

    @PathSensitive(PathSensitivity.NONE)
    @InputFile