Configure pom signing before deployment

Use groovy where kotlin dsl lacks of typed api

buildSrc/src/main/kotlin/plugins/PublishedKotlinModule.kt

@@ -4,6 +4,7 @@ import org.codehaus.groovy.runtime.InvokerHelper
 import org.gradle.api.Plugin
 import org.gradle.api.Project
 import org.gradle.api.artifacts.Dependency
+import org.gradle.api.artifacts.maven.MavenDeployer
 import org.gradle.api.artifacts.maven.MavenResolver
 
 import org.gradle.api.plugins.MavenRepositoryHandlerConvention
@@ -99,11 +100,22 @@ open class PublishedKotlinModule : Plugin<Project> {
 
                 var repository: MavenRemoteRepository by Delegates.notNull()
 
+                val signPom = rootProject.extra["signPom"] as groovy.lang.Closure<*>
+
                 repositories {
                     withConvention(MavenRepositoryHandlerConvention::class) {
 
                         mavenDeployer {
+                            signPom.call(project, this as MavenDeployer)
+
                             withGroovyBuilder {
+                                // TODO: Use with kotlin-dsl 0.12+ instead of signPom
+//                                "beforeDeployment" {
+//                                    val signing = project.the<SigningExtension>()
+//                                    if (signing.isRequired)
+//                                        signing.signPom(this as MavenDeployment)
+//                                }
+
                                 "repository"("url" to repoUrl)!!.also { repository = it as MavenRemoteRepository }.withGroovyBuilder {
                                     if (username != null && password != null) {
                                         "authentication"("userName" to username, "password" to password)

libraries/commonConfiguration.gradle

@@ -116,6 +116,13 @@ task preparePublication {
     }
 }
 
+ext.signPom = { Project project, MavenDeployer deployer ->
+    deployer.beforeDeployment { MavenDeployment deployment ->
+        if (project.signing.required)
+            project.signing.signPom(deployment)
+    }
+}
+
 ext.configurePublishing = { Project project ->
     project.configure(project) {
         apply plugin: 'maven'
@@ -157,10 +164,7 @@ ext.configurePublishing = { Project project ->
 
             repositories {
                 mavenDeployer {
-                    beforeDeployment { MavenDeployment deployment ->
-                        if (signing.required)
-                            signing.signPom(deployment)
-                    }
+                    signPom(project, it)
 
                     repository(url: prepareTask.repoUrl) {
                         authentication(userName: prepareTask.username, password: prepareTask.password)