First steps at making JMH Gradle plugin compatible with Gradle 4

Note that this version would only be compatible with Gradle 4.0+ and Shadow plugin 2.0+. It makes use of the new
worker API, which avoids us doing all the nasty jar repackaging of the runtime of JMH: a worker process is automatically
spawned by Gradle with the appropriate classpath. This means that we can compile this plugin with a specific version
of JMH, but the user can override the version, and we would still use the `Main` entry point instead of an exec task
to execute the benchmarks.

This commit also fixes the [warning issued by Gradle 4.0](#94), which is the main reason for broken compatibility with
released under 4.0: the newer API doesn't exist on 3.5.

This commit however breaks a test with the shadow plugin, and is waiting for the resolution of [this bug](GradleUp/shadow#297).

build.gradle

@@ -15,8 +15,8 @@
  */
 
 plugins {
-    id 'com.gradle.build-scan' version '1.2'
-    id 'me.champeau.buildscan-recipes' version '0.1.3'
+    id 'com.gradle.build-scan' version '1.7.2'
+    id 'me.champeau.buildscan-recipes' version '0.2.0'
     id 'com.jfrog.bintray' version '1.7.3'
     id 'com.jfrog.artifactory' version '4.4.12'
     id 'com.github.hierynomus.license' version '0.11.0'
@@ -31,10 +31,12 @@ buildScan {
     licenseAgreementUrl = 'https://gradle.com/terms-of-service'
     licenseAgree = 'yes'
 
+    publishAlways()
+}
+
+buildScanRecipes {
     recipes 'git-status', 'travis-ci', 'disk-usage', 'gc-stats'
     recipe 'git-commit', baseUrl: 'https://github.com/melix/jmh-gradle-plugin/tree'
-
-    publishAlways()
 }
 
 allprojects {
@@ -50,22 +52,20 @@ apply from: 'gradle/bintray.gradle'
 apply from: 'gradle/artifactory.gradle'
 apply from: 'gradle/code-quality.gradle'
 
-configurations {
-    runner
-}
-
 dependencies {
     compile localGroovy()
     compile gradleApi()
-    compileOnly project(':runner')
-    testCompile project(':runner')
-    runner project(':runner')
+    compile "org.openjdk.jmh:jmh-core:$jmhVersion"
+    compileOnly "org.openjdk.jmh:jmh-generator-bytecode:$jmhVersion"
 
     testCompile "junit:junit:$junitVersion"
     testCompile("org.spockframework:spock-core:$spockVersion") {
         exclude group: 'org.codehaus.groovy', module: 'groovy-all'
     }
     testCompile "com.github.jengelman.gradle.plugins:shadow:$shadowVersion"
+
+    testCompile "org.openjdk.jmh:jmh-core:$jmhVersion"
+    testCompile "org.openjdk.jmh:jmh-generator-bytecode:$jmhVersion"
 }
 
 task release {
@@ -109,8 +109,4 @@ jacocoTestReport {
     }
 }
 
-jar {
-    from configurations.runner
-}
-
 task publishRelease(dependsOn: [bintrayUpload, publishPlugins]) {}

gradle/compile.gradle

@@ -32,3 +32,6 @@ task javadocJar(type: Jar, dependsOn: javadoc) {
     from javadoc.destinationDir
 }
 
+tasks.withType(JavaCompile) {
+    options.incremental = true
+}

gradle/funcTest.gradle

@@ -46,7 +46,7 @@ compileFunctionalTestJava.dependsOn createClasspathManifest
 task functionalTest(type: Test, dependsOn: [jar]) {
     description = 'Runs the functional tests.'
     group = 'verification'
-    testClassesDir = sourceSets.functionalTest.output.classesDir
+    testClassesDirs = sourceSets.functionalTest.output.classesDirs
     classpath = sourceSets.functionalTest.runtimeClasspath
     mustRunAfter test
 

gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.14.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.0-milestone-2-bin.zip

src/main/groovy/me/champeau/gradle/ExtensionOptions.java

@@ -15,7 +15,6 @@
  */
 package me.champeau.gradle;
 
-import me.champeau.jmh.runner.SerializableOptions;
 import org.openjdk.jmh.annotations.Mode;
 import org.openjdk.jmh.results.format.ResultFormatType;
 import org.openjdk.jmh.runner.options.Options;

runner/src/main/java/me/champeau/jmh/runner/Main.java → src/main/groovy/me/champeau/gradle/IsolatedRunner.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2017 the original author or authors.
+ * Copyright 2003-2012 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -13,29 +13,31 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package me.champeau.jmh.runner;
+package me.champeau.gradle;
 
+import org.gradle.api.GradleException;
 import org.openjdk.jmh.runner.Runner;
 import org.openjdk.jmh.runner.RunnerException;
+import org.openjdk.jmh.runner.options.Options;
 
-import java.io.FileInputStream;
-import java.io.IOException;
-import java.io.ObjectInputStream;
+import javax.inject.Inject;
 
-public class Main {
-    public static void main(String[] args) throws IOException, RunnerException, ClassNotFoundException {
-        String optionsFile = args[0];
-        ObjectInputStream ois = null;
-        SerializableOptions options;
+public class IsolatedRunner implements Runnable {
+
+    private final Options options;
+
+    @Inject
+    public IsolatedRunner(final Options options) {
+        this.options = options;
+    }
+
+    @Override
+    public void run() {
+        Runner runner = new Runner(options);
         try {
-            ois = new ObjectInputStream(new FileInputStream(optionsFile));
-            options = (SerializableOptions) ois.readObject();
-        } finally {
-            if (ois != null) {
-                ois.close();
-            }
+            runner.run();
+        } catch (RunnerException e) {
+            throw new GradleException("Error during execution of benchmarks", e);
         }
-        Runner runner = new Runner(options);
-        runner.run();
     }
 }