import java.io.File

fun Configuration.getSingleFileProvider(): Provider<File> {
    val name = this.name
    return incoming.files.elements.map {
        require(it.size <= 1) {
            "Expected at most one file in configuration '$name' but found: $it"
        }
        it.firstOrNull()?.asFile
    }
}

fun NamedDomainObjectProvider<Configuration>.getSingleFileProvider(): Provider<File> {