Fixup the last of the stragglers

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

@@ -312,4 +312,10 @@ public void close() {
 
 	/** This Sentinel reference may be used to pass string content to a Formatter or FormatterStep when there is no actual File to format */
 	public static final File NO_FILE_SENTINEL = new File("NO_FILE_SENTINEL");
+
+	static void checkNotSentinel(File file) {
+		if (file == Formatter.NO_FILE_SENTINEL) {
+			throw new IllegalArgumentException("This step requires the underlying file. If this is a test, use StepHarnessWithFile");
+		}
+	}
 }

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

@@ -115,7 +115,7 @@ public void close() {
 
 				@Override
 				public String apply(String unix, File file) throws Exception {
-					FormatterStepImpl.checkNotSentinel(file);
+					Formatter.checkNotSentinel(file);
 					return function.apply(resource, unix, file);
 				}
 
@@ -144,7 +144,7 @@ interface NeedsFile extends FormatterFunc {
 
 		@Override
 		default String apply(String unix, File file) throws Exception {
-			FormatterStepImpl.checkNotSentinel(file);
+			Formatter.checkNotSentinel(file);
 			return applyWithFile(unix, file);
 		}
 

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

@@ -70,28 +70,6 @@ default FormatterStep filterByFile(SerializableFileFilter filter) {
 		return new FilterByFileFormatterStep(this, filter);
 	}
 
-	/**
-	 * Implements a FormatterStep in a strict way which guarantees correct and lazy implementation
-	 * of up-to-date checks.  This maximizes performance for cases where the FormatterStep is not
-	 * actually needed (e.g. don't load eclipse setting file unless this step is actually running)
-	 * while also ensuring that Gradle can detect changes in a step's settings to determine that
-	 * it needs to rerun a format.
-	 */
-	abstract class Strict<State extends Serializable> extends LazyForwardingEquality<State> implements FormatterStep {
-		private static final long serialVersionUID = 1L;
-
-		/**
-		 * Implements the formatting function strictly in terms
-		 * of the input data and the result of {@link #calculateState()}.
-		 */
-		protected abstract String format(State state, String rawUnix, File file) throws Exception;
-
-		@Override
-		public final String format(String rawUnix, File file) throws Exception {
-			return format(state(), rawUnix, file);
-		}
-	}
-
 	/**
 	 * @param name
 	 *             The name of the formatter step.
@@ -151,8 +129,8 @@ static <RoundtripState extends Serializable, EqualityState extends Serializable>
 	static <State extends Serializable> FormatterStep createLazy(
 			String name,
 			ThrowingEx.Supplier<State> stateSupplier,
-			ThrowingEx.Function<State, FormatterFunc> stateToFormatter) {
-		return new FormatterStepImpl.Standard<>(name, stateSupplier, stateToFormatter);
+			SerializedFunction<State, FormatterFunc> stateToFormatter) {
+		return createLazy(name, stateSupplier, SerializedFunction.identity(), stateToFormatter);
 	}
 
 	/**
@@ -168,7 +146,7 @@ static <State extends Serializable> FormatterStep createLazy(
 	static <State extends Serializable> FormatterStep create(
 			String name,
 			State state,
-			ThrowingEx.Function<State, FormatterFunc> stateToFormatter) {
+			SerializedFunction<State, FormatterFunc> stateToFormatter) {
 		Objects.requireNonNull(state, "state");
 		return createLazy(name, () -> state, stateToFormatter);
 	}

lib/src/main/java/com/diffplug/spotless/cpp/ClangFormatStep.java

@@ -64,10 +64,10 @@ public ClangFormatStep withPathToExe(String pathToExe) {
 	}
 
 	public FormatterStep create() {
-		return FormatterStep.createLazy(name(), this::createState, RoundtripState::state, State::toFunc);
+		return FormatterStep.createLazy(name(), this::createRoundtrip, RoundtripState::toEquality, EqualityState::toFunc);
 	}
 
-	private RoundtripState createState() throws IOException, InterruptedException {
+	private RoundtripState createRoundtrip() throws IOException, InterruptedException {
 		String howToInstall = "" +
 				"You can download clang-format from https://releases.llvm.org and " +
 				"then point Spotless to it with {@code pathToExe('/path/to/clang-format')} " +
@@ -98,13 +98,13 @@ static class RoundtripState implements Serializable {
 			this.exe = exe;
 		}
 
-		private State state() {
-			return new State(version, style, exe);
+		private EqualityState toEquality() {
+			return new EqualityState(version, style, exe);
 		}
 	}
 
 	@SuppressFBWarnings("SE_TRANSIENT_FIELD_NOT_RESTORED")
-	static class State implements Serializable {
+	static class EqualityState implements Serializable {
 		private static final long serialVersionUID = -1825662356883926318L;
 		// used for up-to-date checks and caching
 		final String version;
@@ -113,7 +113,7 @@ static class State implements Serializable {
 		// used for executing
 		private transient @Nullable List<String> args;
 
-		State(String version, @Nullable String style, ForeignExe pathToExe) {
+		EqualityState(String version, @Nullable String style, ForeignExe pathToExe) {
 			this.version = version;
 			this.style = style;
 			this.exe = Objects.requireNonNull(pathToExe);

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 DiffPlug
+ * Copyright 2021-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -35,24 +35,37 @@ private NativeCmdStep() {}
 	public static FormatterStep create(String name, File pathToExe, List<String> arguments) {
 		Objects.requireNonNull(name, "name");
 		Objects.requireNonNull(pathToExe, "pathToExe");
-		return FormatterStep.createLazy(name, () -> new State(FileSignature.signAsList(pathToExe), arguments), State::toFunc);
+		return FormatterStep.createLazy(name, () -> new State(FileSignature.promise(pathToExe), arguments), State::toRuntime, Runtime::toFunc);
 	}
 
 	static class State implements Serializable {
-		private static final long serialVersionUID = 1L;
+		private static final long serialVersionUID = 2L;
+		final FileSignature.Promised pathToExe;
+		final List<String> arguments;
 
-		final FileSignature pathToExe;
+		State(FileSignature.Promised pathToExe, List<String> arguments) {
+			this.pathToExe = pathToExe;
+			this.arguments = arguments;
+		}
+
+		Runtime toRuntime() {
+			return new Runtime(pathToExe.get().getOnlyFile(), arguments);
+		}
+	}
 
+	static class Runtime implements Serializable {
+		private static final long serialVersionUID = 2L;
+		final File pathToExe;
 		final List<String> arguments;
 
-		State(FileSignature pathToExe, List<String> arguments) {
+		Runtime(File pathToExe, List<String> arguments) {
 			this.pathToExe = pathToExe;
 			this.arguments = arguments;
 		}
 
 		String format(ProcessRunner runner, String input) throws IOException, InterruptedException {
 			List<String> argumentsWithPathToExe = new ArrayList<>();
-			argumentsWithPathToExe.add(pathToExe.getOnlyFile().getAbsolutePath());
+			argumentsWithPathToExe.add(pathToExe.getAbsolutePath());
 			if (arguments != null) {
 				argumentsWithPathToExe.addAll(arguments);
 			}

lib/src/main/java/com/diffplug/spotless/go/GofmtFormatStep.java

@@ -63,10 +63,10 @@ public GofmtFormatStep withGoExecutable(String pathToExe) {
 	}
 
 	public FormatterStep create() {
-		return FormatterStep.createLazy(name(), this::createState, GofmtFormatStep.State::toFunc);
+		return FormatterStep.createLazy(name(), this::createRountrip, RoundtripState::toEquality, EqualityState::toFunc);
 	}
 
-	private State createState() throws IOException, InterruptedException {
+	private RoundtripState createRountrip() throws IOException, InterruptedException {
 		String howToInstall = "gofmt is a part of standard go distribution. If spotless can't discover it automatically, " +
 				"you can point Spotless to the go binary with {@code pathToExe('/path/to/go')}";
 		final ForeignExe exe = ForeignExe.nameAndVersion("go", version)
@@ -76,18 +76,34 @@ private State createState() throws IOException, InterruptedException {
 				.fixWrongVersion(
 						"You can tell Spotless to use the version you already have with {@code gofmt('{versionFound}')}" +
 								"or you can install the currently specified Go version, {version}.\n" + howToInstall);
-		return new State(this, exe);
+		return new RoundtripState(version, exe);
+	}
+
+	static class RoundtripState implements Serializable {
+		private static final long serialVersionUID = 1L;
+
+		final String version;
+		final ForeignExe exe;
+
+		RoundtripState(String version, ForeignExe exe) {
+			this.version = version;
+			this.exe = exe;
+		}
+
+		private EqualityState toEquality() {
+			return new EqualityState(version, exe);
+		}
 	}
 
 	@SuppressFBWarnings("SE_TRANSIENT_FIELD_NOT_RESTORED")
-	static class State implements Serializable {
+	static class EqualityState implements Serializable {
 		private static final long serialVersionUID = -1825662355363926318L;
 		// used for up-to-date checks and caching
 		final String version;
 		final transient ForeignExe exe;
 
-		public State(GofmtFormatStep step, ForeignExe goExecutable) {
-			this.version = step.version;
+		public EqualityState(String version, ForeignExe goExecutable) {
+			this.version = version;
 			this.exe = Objects.requireNonNull(goExecutable);
 		}
 

lib/src/main/java/com/diffplug/spotless/python/BlackStep.java

@@ -56,10 +56,10 @@ public BlackStep withPathToExe(String pathToExe) {
 	}
 
 	public FormatterStep create() {
-		return FormatterStep.createLazy(name(), this::createState, RoundtripState::state, State::toFunc);
+		return FormatterStep.createLazy(name(), this::createRoundtrip, RoundtripState::toEquality, EqualityState::toFunc);
 	}
 
-	private RoundtripState createState() {
+	private RoundtripState createRoundtrip() {
 		String trackingIssue = "\n  github issue to handle this better: https://github.com/diffplug/spotless/issues/674";
 		ForeignExe exeAbsPath = ForeignExe.nameAndVersion("black", version)
 				.pathToExe(pathToExe)
@@ -80,21 +80,21 @@ static class RoundtripState implements Serializable {
 			this.exe = exe;
 		}
 
-		private State state() {
-			return new State(version, exe);
+		private EqualityState toEquality() {
+			return new EqualityState(version, exe);
 		}
 	}
 
 	@SuppressFBWarnings("SE_TRANSIENT_FIELD_NOT_RESTORED")
-	static class State implements Serializable {
+	static class EqualityState implements Serializable {
 		private static final long serialVersionUID = -1825662356883926318L;
 		// used for up-to-date checks and caching
 		final String version;
 		final transient ForeignExe exe;
 		// used for executing
 		private transient @Nullable String[] args;
 
-		State(String version, ForeignExe exeAbsPath) {
+		EqualityState(String version, ForeignExe exeAbsPath) {
 			this.version = version;
 			this.exe = Objects.requireNonNull(exeAbsPath);
 		}

lib/src/main/java/com/diffplug/spotless/shell/ShfmtStep.java

@@ -60,10 +60,10 @@ public ShfmtStep withPathToExe(String pathToExe) {
 	}
 
 	public FormatterStep create() {
-		return FormatterStep.createLazy(name(), this::createState, State::toFunc);
+		return FormatterStep.createLazy(name(), this::createRoundtrip, RoundtripState::toEquality, EqualityState::toFunc);
 	}
 
-	private State createState() throws IOException, InterruptedException {
+	private RoundtripState createRoundtrip() throws IOException, InterruptedException {
 		String howToInstall = "" +
 				"You can download shfmt from https://github.com/mvdan/sh and " +
 				"then point Spotless to it with {@code pathToExe('/path/to/shfmt')} " +
@@ -79,11 +79,27 @@ private State createState() throws IOException, InterruptedException {
 				.fixWrongVersion(
 						"You can tell Spotless to use the version you already have with {@code shfmt('{versionFound}')}" +
 								"or you can download the currently specified version, {version}.\n" + howToInstall);
-		return new State(this, exe);
+		return new RoundtripState(version, exe);
+	}
+
+	static class RoundtripState implements Serializable {
+		private static final long serialVersionUID = 1L;
+
+		final String version;
+		final ForeignExe exe;
+
+		RoundtripState(String version, ForeignExe exe) {
+			this.version = version;
+			this.exe = exe;
+		}
+
+		private EqualityState toEquality() {
+			return new EqualityState(version, exe);
+		}
 	}
 
 	@SuppressFBWarnings("SE_TRANSIENT_FIELD_NOT_RESTORED")
-	static class State implements Serializable {
+	static class EqualityState implements Serializable {
 		private static final long serialVersionUID = -1825662356883926318L;
 
 		// used for up-to-date checks and caching
@@ -93,8 +109,8 @@ static class State implements Serializable {
 		// used for executing
 		private transient @Nullable List<String> args;
 
-		State(ShfmtStep step, ForeignExe pathToExe) {
-			this.version = step.version;
+		EqualityState(String version, ForeignExe pathToExe) {
+			this.version = version;
 			this.exe = Objects.requireNonNull(pathToExe);
 		}
 

lib/src/main/java/com/diffplug/spotless/sql/DBeaverSQLFormatterStep.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 DiffPlug
+ * Copyright 2016-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,6 @@
 package com.diffplug.spotless.sql;
 
 import java.io.File;
-import java.io.Serializable;
 
 import com.diffplug.spotless.FileSignature;
 import com.diffplug.spotless.FormatterFunc;
@@ -32,24 +31,14 @@ public class DBeaverSQLFormatterStep {
 	private DBeaverSQLFormatterStep() {}
 
 	public static FormatterStep create(Iterable<File> files) {
-		return FormatterStep.createLazy(NAME,
-				() -> new State(files),
-				State::createFormat);
+		return FormatterStep.create(NAME, FileSignature.promise(files),
+				FileSignature.Promised::get,
+				DBeaverSQLFormatterStep::createFormat);
 	}
 
-	static final class State implements Serializable {
-		private static final long serialVersionUID = 1L;
-
-		final FileSignature settingsSignature;
-
-		State(final Iterable<File> settingsFiles) throws Exception {
-			this.settingsSignature = FileSignature.signAsList(settingsFiles);
-		}
-
-		FormatterFunc createFormat() throws Exception {
-			FormatterProperties preferences = FormatterProperties.from(settingsSignature.files());
-			DBeaverSQLFormatter dbeaverSqlFormatter = new DBeaverSQLFormatter(preferences.getProperties());
-			return dbeaverSqlFormatter::format;
-		}
+	private static FormatterFunc createFormat(FileSignature settings) {
+		FormatterProperties preferences = FormatterProperties.from(settings.files());
+		DBeaverSQLFormatter dbeaverSqlFormatter = new DBeaverSQLFormatter(preferences.getProperties());
+		return dbeaverSqlFormatter::format;
 	}
 }

plugin-gradle/CHANGES.md

@@ -4,6 +4,8 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 
 ## [Unreleased]
 ### Added
+* Full, no-asterisk support of Gradle configuration cache. ([#1274](https://github.com/diffplug/spotless/issues/1274), giving up on [#987](https://github.com/diffplug/spotless/issues/987))
+  * In order to use `custom`, you must now use Gradle 8.0+. 
 * Respect `.editorconfig` settings for formatting shell via `shfmt` ([#2031](https://github.com/diffplug/spotless/pull/2031))
 * Add support for formatting and sorting Maven POMs ([#2082](https://github.com/diffplug/spotless/issues/2082))
 ### Fixed

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

@@ -16,6 +16,7 @@
 package com.diffplug.gradle.spotless;
 
 import static com.diffplug.gradle.spotless.PluginGradlePreconditions.requireElementsNonNull;
+import static com.diffplug.gradle.spotless.SpotlessPluginRedirect.badSemver;
 import static java.util.Objects.requireNonNull;
 
 import java.io.File;
@@ -451,6 +452,12 @@ public String apply(String unixNewlines) {
 	 */
 	public void custom(String name, FormatterFunc formatter) {
 		requireNonNull(formatter, "formatter");
+		if (badSemver(getProject()) < badSemver(SpotlessPlugin.VER_GRADLE_minVersionForCustom)) {
+			throw new GradleException("The 'custom' method is only available if you are using Gradle "
+					+ SpotlessPlugin.VER_GRADLE_minVersionForCustom
+					+ " or newer, this is "
+					+ getProject().getGradle().getGradleVersion());
+		}
 		addStep(FormatterStep.createLazy(name, () -> globalState, SerializedFunction.alwaysReturns(formatter)));
 	}
 

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2023 DiffPlug
+ * Copyright 2016-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -28,6 +28,7 @@ public class SpotlessPlugin implements Plugin<Project> {
 	static final String SPOTLESS_MODERN = "spotlessModern";
 	static final String VER_GRADLE_min = "6.1.1";
 	static final String VER_GRADLE_javaPluginExtension = "7.1";
+	static final String VER_GRADLE_minVersionForCustom = "8.0";
 	private static final int MINIMUM_JRE = 11;
 
 	@Override

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020-2023 DiffPlug
+ * Copyright 2020-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,7 +27,11 @@
 public class SpotlessPluginRedirect implements Plugin<Project> {
 	private static final Pattern BAD_SEMVER = Pattern.compile("(\\d+)\\.(\\d+)");
 
-	private static int badSemver(String input) {
+	static int badSemver(Project project) {
+		return badSemver(project.getGradle().getGradleVersion());
+	}
+
+	static int badSemver(String input) {
 		Matcher matcher = BAD_SEMVER.matcher(input);
 		if (!matcher.find() || matcher.start() != 0) {
 			throw new IllegalArgumentException("Version must start with " + BAD_SEMVER.pattern());
@@ -46,7 +50,7 @@ private static int badSemver(int major, int minor) {
 
 	static boolean gradleIsTooOld(Project project) {
 		if (gradleIsTooOld == null) {
-			gradleIsTooOld = badSemver(project.getGradle().getGradleVersion()) < badSemver(SpotlessPlugin.VER_GRADLE_min);
+			gradleIsTooOld = badSemver(project) < badSemver(SpotlessPlugin.VER_GRADLE_min);
 		}
 		return gradleIsTooOld.booleanValue();
 	}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 DiffPlug
+ * Copyright 2016-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,7 +20,6 @@
 import org.junit.jupiter.api.Test;
 
 class BumpThisNumberIfACustomStepChangesTest extends GradleIntegrationHarness {
-
 	private void writeBuildFile(String toInsert) throws IOException {
 		setFile("build.gradle").toLines(
 				"plugins {",

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

@@ -53,7 +53,7 @@ private Git initRepo() throws IllegalStateException, GitAPIException, IOExceptio
 
 	@Override
 	protected GradleRunner gradleRunner() throws IOException {
-		return super.gradleRunner().withGradleVersion(GradleVersionSupport.CONFIGURATION_CACHE.version);
+		return super.gradleRunner().withGradleVersion(GradleVersionSupport.CUSTOM_STEPS.version);
 	}
 
 	@ParameterizedTest

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2023 DiffPlug
+ * Copyright 2016-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -43,7 +43,7 @@
 
 public class GradleIntegrationHarness extends ResourceHarness {
 	public enum GradleVersionSupport {
-		JRE_11("5.0"), MINIMUM(SpotlessPlugin.VER_GRADLE_min),
+		JRE_11("5.0"), MINIMUM(SpotlessPlugin.VER_GRADLE_min), CUSTOM_STEPS(SpotlessPlugin.VER_GRADLE_minVersionForCustom),
 		// 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"),
 		// https://docs.gradle.org/7.5/userguide/configuration_cache.html#config_cache:stable
@@ -116,8 +116,14 @@ void gitAttributes() throws IOException {
 	}
 
 	protected GradleRunner gradleRunner() throws IOException {
+		GradleVersionSupport version;
+		if (newFile("build.gradle").exists() && read("build.gradle").contains("custom")) {
+			version = GradleVersionSupport.CUSTOM_STEPS;
+		} else {
+			version = GradleVersionSupport.MINIMUM;
+		}
 		return GradleRunner.create()
-				.withGradleVersion(GradleVersionSupport.MINIMUM.version)
+				.withGradleVersion(version.version)
 				.withProjectDir(rootFolder())
 				.withTestKitDir(getTestKitDir())
 				.withPluginClasspath();

testlib/src/main/java/com/diffplug/spotless/StepHarnessBase.java

@@ -27,14 +27,15 @@ enum RoundTrip {
 	private final Formatter formatter;
 
 	protected StepHarnessBase(Formatter formatter, RoundTrip roundTrip) {
-		this.formatter = Objects.requireNonNull(formatter);
 		if (roundTrip == RoundTrip.DONT_ROUNDTRIP) {
+			this.formatter = Objects.requireNonNull(formatter);
 			return;
 		}
 		Formatter roundTripped = SerializableEqualityTester.reserialize(formatter);
 		if (roundTrip == RoundTrip.ASSERT_EQUAL) {
 			Assertions.assertThat(roundTripped).isEqualTo(formatter);
 		}
+		this.formatter = roundTripped;
 	}
 
 	protected Formatter formatter() {

testlib/src/test/java/com/diffplug/spotless/generic/FenceStepTest.java

@@ -16,16 +16,11 @@
 package com.diffplug.spotless.generic;
 
 import java.io.File;
-import java.io.Serializable;
 import java.util.Arrays;
-import java.util.Objects;
-
-import javax.annotation.Nullable;
 
 import org.junit.jupiter.api.Test;
 
 import com.diffplug.common.base.StringPrinter;
-import com.diffplug.spotless.FormatterFunc;
 import com.diffplug.spotless.FormatterStep;
 import com.diffplug.spotless.ResourceHarness;
 import com.diffplug.spotless.StepHarness;
@@ -34,8 +29,8 @@ class FenceStepTest extends ResourceHarness {
 	@Test
 	void single() {
 		FormatterStep fence = FenceStep.named("fence").openClose("spotless:off", "spotless:on")
-				.preserveWithin(Arrays.asList(createNeverUpToDateSerializable("lowercase", String::toLowerCase)));
-		StepHarness harness = StepHarness.forStepNoRoundtrip(fence);
+				.preserveWithin(Arrays.asList(ToCaseStep.lower()));
+		StepHarness harness = StepHarness.forStep(fence);
 		harness.test(
 				StringPrinter.buildStringFromLines(
 						"A B C",
@@ -54,8 +49,8 @@ void single() {
 	@Test
 	void multiple() {
 		FormatterStep fence = FenceStep.named("fence").openClose("spotless:off", "spotless:on")
-				.preserveWithin(Arrays.asList(createNeverUpToDateSerializable("lowercase", String::toLowerCase)));
-		StepHarness harness = StepHarness.forStepNoRoundtrip(fence);
+				.preserveWithin(Arrays.asList(ToCaseStep.lower()));
+		StepHarness harness = StepHarness.forStep(fence);
 		harness.test(
 				StringPrinter.buildStringFromLines(
 						"A B C",
@@ -88,7 +83,7 @@ void multiple() {
 	@Test
 	void broken() {
 		FormatterStep fence = FenceStep.named("fence").openClose("spotless:off", "spotless:on")
-				.preserveWithin(Arrays.asList(createNeverUpToDateSerializable("uppercase", String::toUpperCase)));
+				.preserveWithin(Arrays.asList(ToCaseStep.upper()));
 		// this fails because uppercase turns spotless:off into SPOTLESS:OFF, etc
 		StepHarness.forStepNoRoundtrip(fence).testExceptionMsg(StringPrinter.buildStringFromLines("A B C",
 				"spotless:off",
@@ -100,8 +95,8 @@ void broken() {
 	@Test
 	void andApply() {
 		FormatterStep fence = FenceStep.named("fence").openClose("<lower>", "</lower>")
-				.applyWithin(Arrays.asList(createNeverUpToDateSerializable("lowercase", String::toLowerCase)));
-		StepHarness.forStepNoRoundtrip(fence).test(
+				.applyWithin(Arrays.asList(ToCaseStep.lower()));
+		StepHarness.forStep(fence).test(
 				StringPrinter.buildStringFromLines(
 						"A B C",
 						"<lower>",
@@ -116,46 +111,45 @@ void andApply() {
 						"G H I"));
 	}
 
-	/**
-	 * @param name
-	 *             The name of the formatter step
-	 * @param function
-	 *             The function used by the formatter step
-	 * @return A FormatterStep which will never report that it is up-to-date, because
-	 *         it is not equal to the serialized representation of itself.
-	 */
-	static <T extends FormatterFunc & Serializable> FormatterStep createNeverUpToDateSerializable(
-			String name,
-			T function) {
-		Objects.requireNonNull(function, "function");
-		return new NeverUpToDateSerializable(name, function);
-	}
+	static class ToCaseStep implements FormatterStep {
+		static ToCaseStep upper() {
+			return new ToCaseStep(true);
+		}
 
-	static class NeverUpToDateSerializable<T extends FormatterFunc & Serializable> implements FormatterStep, Serializable {
-		private final String name;
-		private final T formatterFunc;
+		static ToCaseStep lower() {
+			return new ToCaseStep(false);
+		}
+
+		private final boolean uppercase;
 
-		private NeverUpToDateSerializable(String name, T formatterFunc) {
-			this.name = name;
-			this.formatterFunc = formatterFunc;
+		ToCaseStep(boolean uppercase) {
+			this.uppercase = uppercase;
 		}
 
 		@Override
 		public String getName() {
-			return name;
+			return uppercase ? "uppercase" : "lowercase";
 		}
 
-		@Nullable
+		@org.jetbrains.annotations.Nullable
 		@Override
 		public String format(String rawUnix, File file) throws Exception {
-			return formatterFunc.apply(rawUnix, file);
+			return uppercase ? rawUnix.toUpperCase() : rawUnix.toLowerCase();
 		}
 
 		@Override
 		public void close() throws Exception {
-			if (formatterFunc instanceof FormatterFunc.Closeable) {
-				((FormatterFunc.Closeable) formatterFunc).close();
-			}
+
+		}
+
+		@Override
+		public int hashCode() {
+			return getName().hashCode();
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			return obj instanceof ToCaseStep && getName().equals(((ToCaseStep) obj).getName());
 		}
 	}
 }

testlib/src/test/java/com/diffplug/spotless/sql/DBeaverSQLFormatterStepTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 DiffPlug
+ * Copyright 2016-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,7 +29,7 @@
 class DBeaverSQLFormatterStepTest extends ResourceHarness {
 
 	@Test
-	void behavior() throws Exception {
+	void behavior() {
 		FormatterStep step = DBeaverSQLFormatterStep.create(Collections.emptySet());
 		StepHarness.forStep(step)
 				.testResource("sql/dbeaver/full.dirty", "sql/dbeaver/full.clean")
@@ -40,21 +40,21 @@ void behavior() throws Exception {
 	}
 
 	@Test
-	void behaviorWithConfigFile() throws Exception {
+	void behaviorWithConfigFile() {
 		FormatterStep step = DBeaverSQLFormatterStep.create(createTestFiles("sql/dbeaver/sqlConfig.properties"));
 		StepHarness.forStep(step)
 				.testResource("sql/dbeaver/create.dirty", "sql/dbeaver/create.clean");
 	}
 
 	@Test
-	void behaviorWithAlternativeConfigFile() throws Exception {
+	void behaviorWithAlternativeConfigFile() {
 		FormatterStep step = DBeaverSQLFormatterStep.create(createTestFiles("sql/dbeaver/sqlConfig2.properties"));
 		StepHarness.forStep(step)
 				.testResource("sql/dbeaver/create.dirty", "sql/dbeaver/create.clean.alternative");
 	}
 
 	@Test
-	void equality() throws Exception {
+	void equality() {
 		List<File> sqlConfig1 = createTestFiles("sql/dbeaver/sqlConfig.properties");
 		List<File> sqlConfig2 = createTestFiles("sql/dbeaver/sqlConfig2.properties");
 		new SerializableEqualityTester() {