Configuration cache, part 1 (play nice with others)

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/FormatExtension.java

@@ -730,7 +730,7 @@ protected void setupTask(SpotlessTask task) {
 			spotless.getRegisterDependenciesTask().hookSubprojectTask(task);
 		}
 		if (getRatchetFrom() != null) {
-			task.setupRatchet(spotless.getRegisterDependenciesTask().gitRatchet, getRatchetFrom());
+			task.setupRatchet(spotless.getRegisterDependenciesTask().getGitRatchet().get(), getRatchetFrom());
 		}
 	}
 

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/GitRatchetGradle.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020 DiffPlug
+ * Copyright 2020-2021 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,11 +20,15 @@
 import javax.annotation.Nullable;
 
 import org.gradle.api.Project;
+import org.gradle.api.services.BuildService;
+import org.gradle.api.services.BuildServiceParameters;
+import org.gradle.tooling.events.FinishEvent;
+import org.gradle.tooling.events.OperationCompletionListener;
 
 import com.diffplug.spotless.extra.GitRatchet;
 
 /** Gradle implementation of GitRatchet. */
-final class GitRatchetGradle extends GitRatchet<Project> {
+public abstract class GitRatchetGradle extends GitRatchet<Project> implements BuildService<BuildServiceParameters.None>, OperationCompletionListener {
 	@Override
 	protected File getDir(Project project) {
 		return project.getProjectDir();
@@ -34,4 +38,9 @@ protected File getDir(Project project) {
 	protected @Nullable Project getParent(Project project) {
 		return project.getParent();
 	}
+
+	@Override
+	public void onFinish(FinishEvent finishEvent) {
+		// NOOP
+	}
 }

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/RegisterDependenciesTask.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2020 DiffPlug
+ * Copyright 2016-2021 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,23 +20,23 @@
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.function.Function;
-import java.util.stream.Stream;
+
+import javax.inject.Inject;
 
 import org.gradle.api.DefaultTask;
 import org.gradle.api.execution.TaskExecutionGraph;
+import org.gradle.api.provider.Property;
+import org.gradle.api.provider.Provider;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.Internal;
 import org.gradle.api.tasks.OutputFile;
 import org.gradle.api.tasks.TaskAction;
+import org.gradle.build.event.BuildEventsListenerRegistry;
 
 import com.diffplug.common.base.Preconditions;
 import com.diffplug.common.io.Files;
 import com.diffplug.spotless.FormatterStep;
 
-import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
-import groovy.lang.Closure;
-
 /**
  * NOT AN END-USER TASK, DO NOT USE FOR ANYTHING!
  *
@@ -47,7 +47,7 @@
  * - When this "registerDependencies" task does its up-to-date check, it queries the task execution graph to see which
  *   SpotlessTasks are at risk of being executed, and causes them all to be evaluated safely in the root buildscript.
  */
-public class RegisterDependenciesTask extends DefaultTask {
+public abstract class RegisterDependenciesTask extends DefaultTask {
 	static final String TASK_NAME = "spotlessInternalRegisterDependencies";
 
 	@Input
@@ -87,18 +87,13 @@ public GradleProvisioner.RootProvisioner getRootProvisioner() {
 		return rootProvisioner;
 	}
 
-	@SuppressWarnings({"rawtypes", "serial"})
 	void setup() {
 		Preconditions.checkArgument(getProject().getRootProject() == getProject(), "Can only be used on the root project");
 		unitOutput = new File(getProject().getBuildDir(), "tmp/spotless-register-dependencies");
 		rootProvisioner = new GradleProvisioner.RootProvisioner(getProject());
-		getProject().getGradle().buildFinished(new Closure(null) {
-			@SuppressFBWarnings("UMAC_UNCALLABLE_METHOD_OF_ANONYMOUS_CLASS")
-			public Object doCall() {
-				gitRatchet.close();
-				return null;
-			}
-		});
+		Provider<GitRatchetGradle> gitRatchetProvider = getProject().getGradle().getSharedServices().registerIfAbsent("GitRatchetGradle", GitRatchetGradle.class, unused -> {});
+		getBuildEventsListenerRegistry().onTaskCompletion(gitRatchetProvider);
+		getGitRatchet().set(gitRatchetProvider);
 	}
 
 	@TaskAction
@@ -107,10 +102,9 @@ public void trivialFunction() throws IOException {
 		Files.write(Integer.toString(getSteps().size()), unitOutput, StandardCharsets.UTF_8);
 	}
 
-	GitRatchetGradle gitRatchet = new GitRatchetGradle();
-
 	@Internal
-	GitRatchetGradle getGitRatchet() {
-		return gitRatchet;
-	}
+	public abstract Property<GitRatchetGradle> getGitRatchet();
+
+	@Inject
+	protected abstract BuildEventsListenerRegistry getBuildEventsListenerRegistry();
 }

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/SpotlessPlugin.java

@@ -24,7 +24,7 @@
 
 public class SpotlessPlugin implements Plugin<Project> {
 	static final String SPOTLESS_MODERN = "spotlessModern";
-	static final String MINIMUM_GRADLE = "5.4";
+	static final String MINIMUM_GRADLE = "6.1";
 
 	@Override
 	public void apply(Project project) {

plugin-gradle/src/test/java/com/diffplug/gradle/spotless/ConfigurationCacheTest.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2020-2021 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.gradle.spotless;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.Test;
+
+public class ConfigurationCacheTest extends GradleIntegrationHarness {
+	protected void runTasks(String... tasks) throws IOException {
+		setFile("gradle.properties").toContent("org.gradle.unsafe.configuration-cache=true");
+		List<String> args = new ArrayList<>();
+		args.addAll(Arrays.asList(tasks));
+		gradleRunner()
+				.withGradleVersion(GradleVersionSupport.CONFIGURATION_CACHE.version)
+				.withArguments(args)
+				.forwardOutput()
+				.build();
+	}
+
+	@Test
+	public void helpConfigures() throws IOException {
+		setFile("build.gradle").toLines(
+				"buildscript { repositories { mavenCentral() } }",
+				"plugins {",
+				"    id 'com.diffplug.spotless'",
+				"}",
+				"apply plugin: 'java'",
+				"spotless {",
+				"    java {",
+				"        googleJavaFormat('1.2')",
+				"    }",
+				"}");
+		runTasks("help");
+	}
+
+	@Test
+	public void helpConfiguresIfTasksAreCreated() throws IOException {
+		setFile("build.gradle").toLines(
+				"buildscript { repositories { mavenCentral() } }",
+				"plugins {",
+				"    id 'com.diffplug.spotless'",
+				"}",
+				"apply plugin: 'java'",
+				"spotless {",
+				"    java {",
+				"        googleJavaFormat('1.2')",
+				"    }",
+				"}",
+				"tasks.named('spotlessJavaApply').get()");
+		runTasks("help");
+	}
+}

plugin-gradle/src/test/java/com/diffplug/gradle/spotless/GitRatchetGradleTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2020 DiffPlug
+ * Copyright 2016-2021 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -128,11 +128,11 @@ private void assertDirty() throws Exception {
 	}
 
 	private BuildResultAssertion assertPass(String... tasks) throws Exception {
-		return new BuildResultAssertion(gradleRunner().withGradleVersion(GradleVersionSupport.SETTINGS_PLUGINS.version).withArguments(tasks).build());
+		return new BuildResultAssertion(gradleRunner().withArguments(tasks).build());
 	}
 
 	private BuildResultAssertion assertFail(String... tasks) throws Exception {
-		return new BuildResultAssertion(gradleRunner().withGradleVersion(GradleVersionSupport.SETTINGS_PLUGINS.version).withArguments(tasks).buildAndFail());
+		return new BuildResultAssertion(gradleRunner().withArguments(tasks).buildAndFail());
 	}
 
 	private static final String BASELINE_ROOT = "cf049829afeba064f27cd67911dc36e585c9d869";

plugin-gradle/src/test/java/com/diffplug/gradle/spotless/GradleIntegrationHarness.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2020 DiffPlug
+ * Copyright 2016-2021 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -39,7 +39,9 @@
 
 public class GradleIntegrationHarness extends ResourceHarness {
 	public enum GradleVersionSupport {
-		JRE_11("5.0"), MINIMUM(SpotlessPlugin.MINIMUM_GRADLE), SETTINGS_PLUGINS("6.0");
+		JRE_11("5.0"), MINIMUM(SpotlessPlugin.MINIMUM_GRADLE),
+		// technically, this API exists in 6.5, but the flags for it change in 6.6, so we build to that
+		CONFIGURATION_CACHE("6.6");
 
 		final String version;
 

plugin-gradle/src/test/java/com/diffplug/gradle/spotless/SpotlessPluginRedirectTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020 DiffPlug
+ * Copyright 2020-2021 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -52,7 +52,7 @@ public void redirectPluginOldGradle() throws IOException {
 						"   > We have moved from 'com.diffplug.gradle.spotless'",
 						"                     to 'com.diffplug.spotless'",
 						"     To migrate:",
-						"     - Upgrade gradle to 5.4 or newer (you're on 5.0)",
+						"     - Upgrade gradle to 6.1 or newer (you're on 5.0)",
 						"     - Test your build with: id 'com.diffplug.gradle.spotless' version '4.5.1'"));
 	}
 
@@ -66,6 +66,6 @@ public void realPluginOldGradle() throws IOException {
 		Assertions.assertThat(gradleRunner().withGradleVersion(GradleVersionSupport.JRE_11.version)
 				.buildAndFail().getOutput().replace("\r", ""))
 				.contains(StringPrinter.buildStringFromLines(
-						"Spotless requires Gradle 5.4 or newer, this was 5.0"));
+						"Spotless requires Gradle 6.1 or newer, this was 5.0"));
 	}
 }