In upgrading to 5.1.1, I was also forced to switch from maven to maven-plugin due to bugs in signing. I have a subprojects { } section that defines the entire pom for ‘every’ single project(21 projects). Each project previously overloaded the description so I modified the tree to now look like this in each project to overload it
publishing.repositories.publications.mavenJava.pom {
description=‘NIO wrapper on top of core-channelmanager2 making creating a tcp server just 3 lines of code’
}
That now fails with “Could not get unknown property ‘publications’ for repository container of type org.gradle.api.internal.artifacts.dsl.DefaultRepositoryHandler”
My top level pom code is
publishing {
repositories {
maven {
name = 'sonatype'
url = "https://oss.sonatype.org/service/local/staging/deploy/maven2/"
credentials {
username = sonatypeUsername
password = sonatypePassword
}
}
maven {
name = 'local'
url = "file://${buildDir}/repo"
}
}
publications {
mavenJava(MavenPublication) {
from components.java
pom {
name = project.name
description = "testing this out"
//'Someone forgot to fill this in. See http://stackoverflow.com/questions/38272550/how-to-fail-the-gradle-build-if-subproject-is-missing-a-property'
url = 'https://github.com/${github_org}/${project_name}'
licenses {
license {
name = 'The Apache License, Version 2.0'
url = 'http://www.apache.org/licenses/LICENSE-2.0.txt'
}
}
developers {
developer {
id = 'dhiller'
name = 'Dean Hiller'
}
}
scm {
connection = "scm:git:https://github.com/${github_org}/${project_name}.git"
developerConnection = "scm:git:git@github.com:${github_org}/${project_name}.git"
url = "https://github.com/${github_org}/${project_name}.git"
}
}
artifact sourcesJar
}
}
}
I also tried this in each project
description = “My description of this project”
and then in the pom file, I did
description = project.description
but that didn’t work either 
and in fact did not even fail but generated a pom with an empty description.
And of course, sonatype won’t let me upload without a description so I am blocked on this.