Maven publication closure is evaluated too early

build.gradle

group 'org.behrang.labs'
version '1.0-SNAPSHOT'

apply plugin: 'maven-publish'

repositories {
    mavenCentral()
}

task clean {
    doLast {
        println "clean"

        if (buildDir.exists()) {
            buildDir.listFiles().each { f -> f.delete() }
        }
    }
}

task randomArtifacts {
    doLast {
        println "randomArtifacts"

        buildDir.mkdirs();

        def artifactCount = (int) (Math.random() * 9) + 1
        (1..artifactCount).each {
            new File(buildDir, "artifact-${it}.rpm").text = "Artifact ${it}"
        }

        println "Created ${artifactCount} artifacts."
    }
}

publishing {
    publications {
        mavenRpm(MavenPublication) {
            println "mavenRpm"

            def rpms = buildDir.listFiles({ f -> f.name.endsWith(".rpm")} as FileFilter)
            rpms.each { f ->
                println f.absolutePath
            }
        }
    }
}