gradle publish does not pick up artifacts: "Task has not declared any outputs despite executing actions." - gradle

Question

I'm migrating a java project from gradle 2.x to 5.3.1.
The last problem is that no artefacts (a tar in our case) are published to artifactory.
The config in main build.gradle is
subprojects {
apply plugin: "com.jfrog.artifactory"
project.ext {
artifactoryConfig = new File(project.gradle.gradleUserHomeDir, "artifactory.gradle")
}
if (artifactoryConfig.exists()) {
apply plugin: 'maven'
apply from: artifactoryConfig
}
sourceCompatibility = 1.8
repositories {
mavenCentral()
maven { url $OUR_ARTIFACTORY }
}
publishing {
publications {
mavenJava(MavenPublication) {
from components.java
}
}
}
}
artifactory {
publish {
contextUrl = "${artifactoryBaseUrl}"
repository {
repoKey = "libs-release-local"
username = "${artifactoryUsername}"
password = "${artifactoryPassword}"
}
}
resolve {
repoKey = 'repos'
}
}
And in the module
task('dist', type: Tar) {
dependsOn('jar')
archiveName "$MODULE-${version}.${extension}"
...
}
publishing {
publications {
mavenJava(MavenPublication)
{
artifact dist {
}
}
}
}
configurations.archives.artifacts.clear()
artifacts {
archives dist
}
Now when I do ./gradlew --info :$MODULE:artifactoryPublish it complains about missing outputs and does not publish the tar to artifactory.
How to fix this?
> Task :$MODULE:artifactoryPublish
Task ':$MODULE:artifactoryPublish' is not up-to-date because:
Task has not declared any outputs despite executing actions.
:$MODULE:artifactoryPublish (Thread[Execution worker for ':',5,main]) completed. Took 0.002 secs.
:artifactoryDeploy (Thread[Execution worker for ':',5,main]) started.
> Task :artifactoryDeploy
Task ':artifactoryDeploy' is not up-to-date because:
Task has not declared any outputs despite executing actions.
Deploying build descriptor to: $OUR_ARTIFACTORY/artifactory/api/build
Build successfully deployed. Browse it in Artifactory under $OUR_ARTIFACTORY/artifactory/webapp/builds/$MODULE/1554465369336
:artifactoryDeploy (Thread[Execution worker for ':',5,main]) completed. Took 0.155 secs.

Answer 1

Turns out the solution was to add
artifactoryPublish {
publications('mavenJava')
}

Answer 2

For me the problem was that the url and credentials were null. It resulted in the same error message(Task has not declared any outputs).
artifactory {
contextUrl = artifactoryUrl
publish {
repository {
username = artifactoryPublishUser
password = artifactoryPublishPassword

Answer 3

The most valuable hint is a running example
https://github.com/jfrog/project-examples/tree/master/gradle-examples/gradle-android-example