Serializable Groovy, Java, Kotlin, and Scala steps

lib-extra/src/main/java/com/diffplug/spotless/extra/EclipseBasedStepBuilder.java

@@ -33,6 +33,7 @@
 import com.diffplug.spotless.FormatterStep;
 import com.diffplug.spotless.JarState;
 import com.diffplug.spotless.Provisioner;
+import com.diffplug.spotless.RoundedStep;
 import com.diffplug.spotless.SerializedFunction;
 
 /**
@@ -126,7 +127,7 @@ public void setPreferences(Iterable<File> settingsFiles) {
 		this.settingsFiles = settingsFiles;
 	}
 
-	static class EclipseStep implements Serializable {
+	static class EclipseStep implements RoundedStep {
 		private static final long serialVersionUID = 1;
 		private final String semanticVersion;
 		private final String formatterStepExt;

lib-extra/src/main/java/com/diffplug/spotless/extra/EquoBasedStepBuilder.java

@@ -34,6 +34,7 @@
 import com.diffplug.spotless.FormatterStep;
 import com.diffplug.spotless.JarState;
 import com.diffplug.spotless.Provisioner;
+import com.diffplug.spotless.RoundedStep;
 import com.diffplug.spotless.SerializedFunction;
 
 import dev.equo.solstice.NestedJars;
@@ -149,7 +150,7 @@ private P2Model createModelWithMirrors() {
 		return model;
 	}
 
-	static class EquoStep implements Serializable {
+	static class EquoStep implements RoundedStep {
 		private static final long serialVersionUID = 1;
 		private final String semanticVersion;
 		private final FileSignature.Promised settingsPromise;

lib/src/main/java/com/diffplug/spotless/RoundedStep.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2024 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.spotless;
+
+import java.io.Serializable;
+
+public interface RoundedStep extends Serializable {}

lib/src/main/java/com/diffplug/spotless/generic/IndentStep.java

@@ -15,14 +15,13 @@
  */
 package com.diffplug.spotless.generic;
 
-import java.io.Serializable;
-
 import com.diffplug.spotless.FormatterFunc;
 import com.diffplug.spotless.FormatterStep;
+import com.diffplug.spotless.RoundedStep;
 import com.diffplug.spotless.SerializedFunction;
 
 /** Simple step which checks for consistent indentation characters. */
-public final class IndentStep implements Serializable {
+public final class IndentStep implements RoundedStep {
 	private static final long serialVersionUID = 1L;
 
 	final Type type;

lib/src/main/java/com/diffplug/spotless/groovy/RemoveSemicolonsStep.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023 DiffPlug
+ * Copyright 2023-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,23 +21,25 @@
 
 import com.diffplug.spotless.FormatterFunc;
 import com.diffplug.spotless.FormatterStep;
+import com.diffplug.spotless.RoundedStep;
 
 /**
  * Removes all semicolons from the end of lines.
  *
  * @author Jose Luis Badano
  */
-public final class RemoveSemicolonsStep {
+public final class RemoveSemicolonsStep implements RoundedStep {
+	private static final long serialVersionUID = 1L;
 	private static final String NAME = "Remove unnecessary semicolons";
 
 	private RemoveSemicolonsStep() {
 		// do not instantiate
 	}
 
 	public static FormatterStep create() {
-		return FormatterStep.createLazy(NAME,
-				State::new,
-				RemoveSemicolonsStep.State::toFormatter);
+		return FormatterStep.create(NAME,
+				new State(),
+				State::toFormatter);
 	}
 
 	private static final class State implements Serializable {
@@ -64,7 +66,7 @@ FormatterFunc toFormatter() {
 		 * @return the line without the last semicolon
 		 */
 		private String removeSemicolon(String line) {
-			// find last semicolon in a string a remove it
+			// Find the last semicolon in a string and remove it.
 			int lastSemicolon = line.lastIndexOf(";");
 			if (lastSemicolon != -1 && lastSemicolon == line.length() - 1) {
 				return line.substring(0, lastSemicolon);

lib/src/main/java/com/diffplug/spotless/java/CleanthatJavaStep.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023 DiffPlug
+ * Copyright 2023-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,7 +15,6 @@
  */
 package com.diffplug.spotless.java;
 
-import java.io.IOException;
 import java.io.Serializable;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
@@ -27,30 +26,51 @@
 import com.diffplug.spotless.JarState;
 import com.diffplug.spotless.Jvm;
 import com.diffplug.spotless.Provisioner;
+import com.diffplug.spotless.RoundedStep;
 
 /**
  * Enables CleanThat as a SpotLess step.
  *
  * @author Benoit Lacelle
  */
 // https://github.com/diffplug/spotless/blob/main/CONTRIBUTING.md#how-to-add-a-new-formatterstep
-public final class CleanthatJavaStep {
-
+public final class CleanthatJavaStep implements RoundedStep {
+	private static final long serialVersionUID = 1L;
 	private static final String NAME = "cleanthat";
 	private static final String MAVEN_COORDINATE = "io.github.solven-eu.cleanthat:java";
-
-	// CleanThat changelog is available at https://github.com/solven-eu/cleanthat/blob/master/CHANGES.MD
+	/**
+	 * CleanThat changelog is available at <a href="https://github.com/solven-eu/cleanthat/blob/master/CHANGES.MD">here</a>.
+	 */
 	private static final Jvm.Support<String> JVM_SUPPORT = Jvm.<String> support(NAME).add(11, "2.16");
 
-	// prevent direct instantiation
-	private CleanthatJavaStep() {}
+	private final JarState.Promised jarState;
+	private final String version;
+	private final String sourceJdkVersion;
+	private final List<String> included;
+	private final List<String> excluded;
+	private final boolean includeDraft;
+
+	private CleanthatJavaStep(JarState.Promised jarState,
+			String version,
+			String sourceJdkVersion,
+			List<String> included,
+			List<String> excluded,
+			boolean includeDraft) {
+		this.jarState = jarState;
+		this.version = version;
+
+		this.sourceJdkVersion = sourceJdkVersion;
+		this.included = included;
+		this.excluded = excluded;
+		this.includeDraft = includeDraft;
+	}
 
-	/** Creates a step which apply default CleanThat mutators. */
+	/** Creates a step that applies default CleanThat mutators. */
 	public static FormatterStep create(Provisioner provisioner) {
 		return create(defaultVersion(), provisioner);
 	}
 
-	/** Creates a step which apply default CleanThat mutators. */
+	/** Creates a step that applies default CleanThat mutators. */
 	public static FormatterStep create(String version, Provisioner provisioner) {
 		return create(MAVEN_COORDINATE, version, defaultSourceJdk(), defaultMutators(), defaultExcludedMutators(), defaultIncludeDraft(), provisioner);
 	}
@@ -64,7 +84,6 @@ public static String defaultSourceJdk() {
 
 	/**
 	 * By default, we include only safe and consensual mutators
-	 * @return
 	 */
 	public static List<String> defaultMutators() {
 		// see ICleanthatStepParametersProperties.SAFE_AND_CONSENSUAL
@@ -79,7 +98,7 @@ public static boolean defaultIncludeDraft() {
 		return false;
 	}
 
-	/** Creates a step which apply selected CleanThat mutators. */
+	/** Creates a step that applies selected CleanThat mutators. */
 	public static FormatterStep create(String groupArtifact,
 			String version,
 			String sourceJdkVersion,
@@ -93,57 +112,51 @@ public static FormatterStep create(String groupArtifact,
 		}
 		Objects.requireNonNull(version, "version");
 		Objects.requireNonNull(provisioner, "provisioner");
-		return FormatterStep.createLazy(NAME,
-				() -> new JavaRefactorerState(NAME, groupArtifact, version, sourceJdkVersion, included, excluded, includeDraft, provisioner),
-				JavaRefactorerState::createFormat);
+		return FormatterStep.create(NAME,
+				new CleanthatJavaStep(JarState.promise(() -> JarState.from(groupArtifact + ":" + version, provisioner)), version, sourceJdkVersion, included, excluded, includeDraft),
+				CleanthatJavaStep::equalityState,
+				State::createFormat);
 	}
 
 	/** Get default formatter version */
 	public static String defaultVersion() {
-		return JVM_SUPPORT.getRecommendedFormatterVersion();
+		return Objects.requireNonNull(JVM_SUPPORT.getRecommendedFormatterVersion());
 	}
 
 	public static String defaultGroupArtifact() {
 		return MAVEN_COORDINATE;
 	}
 
-	static final class JavaRefactorerState implements Serializable {
-		private static final long serialVersionUID = 1L;
-
-		final JarState jarState;
-		final String stepName;
-		final String version;
+	private State equalityState() {
+		return new State(jarState.get(), version, sourceJdkVersion, included, excluded, includeDraft);
+	}
 
-		final String sourceJdkVersion;
-		final List<String> included;
-		final List<String> excluded;
-		final boolean includeDraft;
+	private static final class State implements Serializable {
+		private static final long serialVersionUID = 1L;
 
-		JavaRefactorerState(String stepName, String version, Provisioner provisioner) throws IOException {
-			this(stepName, MAVEN_COORDINATE, version, defaultSourceJdk(), defaultMutators(), defaultExcludedMutators(), defaultIncludeDraft(), provisioner);
-		}
+		private final JarState jarState;
+		private final String version;
+		private final String sourceJdkVersion;
+		private final List<String> included;
+		private final List<String> excluded;
+		private final boolean includeDraft;
 
-		JavaRefactorerState(String stepName,
-				String groupArtifact,
+		State(JarState jarState,
 				String version,
 				String sourceJdkVersion,
 				List<String> included,
 				List<String> excluded,
-				boolean includeDraft,
-				Provisioner provisioner) throws IOException {
+				boolean includeDraft) {
 			JVM_SUPPORT.assertFormatterSupported(version);
 			ModuleHelper.doOpenInternalPackagesIfRequired();
-			this.jarState = JarState.from(groupArtifact + ":" + version, provisioner);
-			this.stepName = stepName;
+			this.jarState = jarState;
 			this.version = version;
-
 			this.sourceJdkVersion = sourceJdkVersion;
 			this.included = included;
 			this.excluded = excluded;
 			this.includeDraft = includeDraft;
 		}
 
-		@SuppressWarnings("PMD.UseProperClassLoader")
 		FormatterFunc createFormat() {
 			ClassLoader classLoader = jarState.getClassLoader();
 
@@ -159,9 +172,7 @@ FormatterFunc createFormat() {
 				throw new IllegalStateException("Issue executing the formatter", e);
 			}
 
-			return JVM_SUPPORT.suggestLaterVersionOnError(version, input -> {
-				return (String) formatterMethod.invoke(formatter, input);
-			});
+			return JVM_SUPPORT.suggestLaterVersionOnError(version, input -> (String) formatterMethod.invoke(formatter, input));
 		}
 	}
 }

lib/src/main/java/com/diffplug/spotless/java/FormatAnnotationsStep.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022-2023 DiffPlug
+ * Copyright 2022-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,6 +26,8 @@
 
 import com.diffplug.spotless.FormatterFunc;
 import com.diffplug.spotless.FormatterStep;
+import com.diffplug.spotless.RoundedStep;
+import com.diffplug.spotless.SerializedFunction;
 
 /**
  * Some formatters put every annotation on its own line
@@ -36,7 +38,8 @@
  * <p>
  * Note: A type annotation is an annotation that is meta-annotated with {@code @Target({ElementType.TYPE_USE})}.
  */
-public final class FormatAnnotationsStep {
+public final class FormatAnnotationsStep implements RoundedStep {
+	private static final long serialVersionUID = 1L;
 
 	/**
 	 * Simple names of type annotations.
@@ -389,14 +392,14 @@ public final class FormatAnnotationsStep {
 
 			);
 
-	static final String NAME = "No line break between type annotation and type";
+	private static final String NAME = "No line break between type annotation and type";
 
 	public static FormatterStep create() {
 		return create(Collections.emptyList(), Collections.emptyList());
 	}
 
 	public static FormatterStep create(List<String> addedTypeAnnotations, List<String> removedTypeAnnotations) {
-		return FormatterStep.create(NAME, new State(addedTypeAnnotations, removedTypeAnnotations), State::toFormatter);
+		return FormatterStep.create(NAME, new State(addedTypeAnnotations, removedTypeAnnotations), SerializedFunction.identity(), State::toFormatter);
 	}
 
 	private FormatAnnotationsStep() {}
@@ -432,13 +435,13 @@ private static final class State implements Serializable {
 		}
 
 		FormatterFunc toFormatter() {
-			return unixStr -> fixupTypeAnnotations(unixStr);
+			return this::fixupTypeAnnotations;
 		}
 
 		/**
 		 * Removes line break between type annotations and the following type.
 		 *
-		 * @param the text of a Java file
+		 * @param unixStr the text of a Java file
 		 * @return corrected text of the Java file
 		 */
 		String fixupTypeAnnotations(String unixStr) {