fix split repos when publishing to Sonatype Nexus

Unfortunately the Gradle Publish Plugin behaves erratically in combination with Sonatype Nexus. In particular if timing is bad, split repositories will be created. The only way I could find to mitigate this problem is the `de.marcphilipp.nexus-publish` plugin, which will create a Sonatype repository in a pre-step, then publish all artifacts to this repository. As far as I could see it works fine for releases and snapshots, has a shorter config and solves the problem at hand. Also compare gradle/gradle#5711

Signed-off-by: Peter Gafert <[email protected]>

build-steps/release/publish.gradle

@@ -10,6 +10,7 @@ if (!hasProperty("sonatypePassword")) {
 releaseProjects*.with {
     apply plugin: "maven-publish"
     apply plugin: "signing"
+    apply plugin: "de.marcphilipp.nexus-publish"
 
     tasks.withType(GenerateModuleMetadata) {
         enabled = false // the meta-data does not match the way the Maven artifacts are composed and thus is broken
@@ -82,22 +83,11 @@ releaseProjects*.with {
             }
         }
 
-        repositories {
-            // respective username and password can be configured in ~/.gradle/gradle.properties
-            if (project.hasProperty('sonatypeUsername') && project.hasProperty('sonatypePassword')) {
-                maven {
-                    def releasesRepoUrl = "https://oss.sonatype.org/service/local/staging/deploy/maven2/"
-                    def snapshotRepoUrl = "https://oss.sonatype.org/content/repositories/snapshots/"
-                    url = isReleaseVersion ? releasesRepoUrl : snapshotRepoUrl
-
-                    credentials {
-                        username = sonatypeUsername
-                        password = sonatypePassword
-                    }
-
-                    metadataSources {
-                        gradleMetadata()
-                    }
+        // respective username and password can be configured in ~/.gradle/gradle.properties
+        if (project.hasProperty('sonatypeUsername') && project.hasProperty('sonatypePassword')) {
+            nexusPublishing {
+                repositories {
+                    sonatype()
                 }
             }
         }

build.gradle

@@ -1,6 +1,7 @@
 plugins {
     id 'com.github.johnrengelman.shadow' version '5.2.0' apply false
     id 'com.github.spotbugs' version '4.0.5' apply false
+    id "de.marcphilipp.nexus-publish" version "0.4.0" apply false
 }
 
 def appAndSourceUrl = 'https://github.com/TNG/ArchUnit'