Extract checkLibVersions task to gradle plugin

build.gradle.kts

@@ -2,6 +2,7 @@ plugins {
     java
     application
     eclipse
+    `check-lib-versions`
 }
 
 version = "0.7.4"
@@ -57,39 +58,6 @@ tasks.withType<JavaExec> {
     }
 }
 
-// Find any 3rd party libraries which have released new versions
-// to the central Maven repo since we last upgraded.
-val checkLibVersions by tasks.registering {
-    doLast {
-        val checked = kotlin.collections.HashSet<Dependency>()
-        allprojects {
-            configurations.forEach { configuration ->
-                configuration.allDependencies.forEach { dependency ->
-                    val version = dependency.version
-                    if (!checked.contains(dependency)) {
-                        val group = dependency.group
-                        val path = group?.replace(".", "/") ?: ""
-                        val name = dependency.name
-                        val metaDataUrl = "https://repo1.maven.org/maven2/$path/$name/maven-metadata.xml"
-                        try {
-                            val url = org.codehaus.groovy.runtime.ResourceGroovyMethods.toURL(metaDataUrl)
-                            val metaDataText = org.codehaus.groovy.runtime.ResourceGroovyMethods.getText(url)
-                            val metadata = groovy.util.XmlSlurper().parseText(metaDataText)
-                            val newest = (metadata.getProperty("versioning") as groovy.util.slurpersupport.GPathResult).getProperty("latest")
-                            if (version != newest.toString()) {
-                                println("UPGRADE {\"group\": \"$group\", \"name\": \"$name\", \"current\": \"$version\", \"latest\": \"$newest\"}")
-                            }
-                        } catch (e: Throwable) {
-                            logger.debug("Unable to download or parse $metaDataUrl: $e.message")
-                        }
-                        checked.add(dependency)
-                    }
-                }
-            }
-        }
-    }
-}
-
 val assembleNativeImage by tasks.registering {
     dependsOn("assemble")
 

buildSrc/build.gradle.kts

@@ -0,0 +1,16 @@
+plugins {
+    `kotlin-dsl`
+}
+
+repositories {
+    jcenter()
+}
+
+gradlePlugin {
+    plugins {
+        register("check-lib-versions") {
+            id = "check-lib-versions"
+            implementationClass = "CheckLibVersionsPlugin"
+        }
+    }
+}

buildSrc/src/main/kotlin/CheckLibVersionsPlugin.kt

@@ -0,0 +1,39 @@
+import groovy.util.XmlSlurper
+import groovy.util.slurpersupport.GPathResult
+import org.codehaus.groovy.runtime.ResourceGroovyMethods
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+import org.gradle.api.Task
+import org.gradle.api.artifacts.Dependency
+
+class CheckLibVersionsPlugin : Plugin<Project> {
+    override fun apply(project: Project) {
+        project.task("checkLibVersions") {
+            description = "Find any 3rd party libraries which have released new versions to the central Maven repo since we last upgraded."
+            doLast {
+                project.configurations.flatMap { it.allDependencies }
+                        .toSet()
+                        .forEach { checkDependency(it) }
+            }
+        }
+    }
+
+    private fun Task.checkDependency(dependency: Dependency) {
+        val version = dependency.version
+        val group = dependency.group
+        val path = group?.replace(".", "/") ?: ""
+        val name = dependency.name
+        val metaDataUrl = "https://repo1.maven.org/maven2/$path/$name/maven-metadata.xml"
+        try {
+            val url = ResourceGroovyMethods.toURL(metaDataUrl)
+            val metaDataText = ResourceGroovyMethods.getText(url)
+            val metadata = XmlSlurper().parseText(metaDataText)
+            val newest = (metadata.getProperty("versioning") as GPathResult).getProperty("latest")
+            if (version != newest.toString()) {
+                println("UPGRADE {\"group\": \"$group\", \"name\": \"$name\", \"current\": \"$version\", \"latest\": \"$newest\"}")
+            }
+        } catch (e: Throwable) {
+            logger.debug("Unable to download or parse $metaDataUrl: $e.message")
+        }
+    }
+}

lib/build.gradle.kts

@@ -1,5 +1,6 @@
 plugins {
     `java-library`
+    `check-lib-versions`
 }
 
 java {