<http://logger.info|logger.info>("loading configuration")

        val rootFolder = File(".").absoluteFile
        val configFolder = rootFolder.resolve("config")
        configFolder.mkdirs()

        val baseFile = configFolder.resolve("base.hocon")

        val parser = ConfigParser()

        val config = ConfigFactory.parseFile(baseFile)
        println(config)
        val baseConfig = parser.parse(config, BaseConfiguration.serializer())

        println(baseConfig)

BaseConfiguration is

@Serializable
data class BaseConfiguration (
    @Optional var ids: List<Int> = listOf(),
    @Optional var strings: List<String> = listOf()
)

This? https://github.com/Kotlin/kotlinx.serialization/issues/211

must have been blind, sorry