[Experimental] Add rewrite support for errorprone.refasterrules.StringRulesRecipes

Author: Vincent Potucek

.github/workflows/ci.yml

@@ -31,6 +31,8 @@ jobs:
         uses: gradle/actions/setup-gradle@v4
       - name: spotlessCheck
         run: ./gradlew spotlessCheck
+      - name: rewriteDryRun
+        run: ./gradlew rewriteDryRun
       - name: assemble testClasses
         run: ./gradlew assemble testClasses
   build:
@@ -66,10 +68,10 @@ jobs:
         uses: gradle/actions/setup-gradle@v4
       - name: build (maven-only)
         if: matrix.kind == 'maven'
-        run: ./gradlew :plugin-maven:build -x spotlessCheck
+        run: ./gradlew :plugin-maven:build -x spotlessCheck -x rewriteDryRun
       - name: build (everything-but-maven)
         if: matrix.kind == 'gradle'
-        run: ./gradlew build -x spotlessCheck -PSPOTLESS_EXCLUDE_MAVEN=true
+        run: ./gradlew build -x spotlessCheck -x rewriteDryRun -PSPOTLESS_EXCLUDE_MAVEN=true
       - name: test npm
         if: matrix.kind == 'npm'
         run: ./gradlew testNpm

CHANGES.md

@@ -16,6 +16,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
   * Adds support for worktrees (fixes [#1765](https://github.com/diffplug/spotless/issues/1765))
 * Bump default `google-java-format` version to latest `1.24.0` -> `1.28.0`. ([#2345](https://github.com/diffplug/spotless/pull/2345))
 * Bump default `ktlint` version to latest `1.5.0` -> `1.7.1`. ([#2555](https://github.com/diffplug/spotless/pull/2555))
+* [Experimental] Add `rewrite` support for `RemoveUnusedPrivateMethods` & `RemoveUnusedImports` ([#2576](https://github.com/diffplug/spotless/pull/2576))
 
 ## [3.3.1] - 2025-07-21
 ### Fixed

build.gradle

@@ -1,4 +1,14 @@
 apply plugin: 'dev.equo.ide'
+
+apply from: rootProject.file('gradle/changelog.gradle')
+apply from: rootProject.file('gradle/java-publish.gradle')
+apply from: rootProject.file('gradle/spotless-freshmark.gradle')
+
+allprojects {
+	apply from: rootProject.file('gradle/spotless.gradle')
+	apply from: rootProject.file('gradle/rewrite.gradle')
+}
+
 equoIde {
 	branding().title('Spotless').icon(file('_images/spotless_logo.png'))
 	welcome().openUrl('https://github.com/diffplug/spotless/blob/main/CONTRIBUTING.md')
@@ -9,21 +19,10 @@ repositories {
 	mavenCentral()
 }
 
-apply from: rootProject.file('gradle/java-publish.gradle')
-apply from: rootProject.file('gradle/changelog.gradle')
-allprojects {
-	apply from: rootProject.file('gradle/spotless.gradle')
-}
-apply from: rootProject.file('gradle/spotless-freshmark.gradle')
-
-spotless {
-	groovyGradle {
-		target '*.gradle', 'gradle/*.gradle'
-	}
-	format 'dotfiles', {
-		target '.gitignore', '.gitattributes', '.editorconfig'
-		leadingTabsToSpaces(2)
-		trimTrailingWhitespace()
-		endWithNewline()
-	}
+dependencies {
+	rewrite(
+			"org.openrewrite.recipe:rewrite-rewrite:0.10.1",
+			"org.openrewrite.recipe:rewrite-static-analysis:2.12.0",
+			"org.openrewrite.recipe:rewrite-third-party:0.24.1"
+			)
 }

gradle/rewrite.gradle

@@ -0,0 +1,61 @@
+apply plugin: 'org.openrewrite.rewrite'
+
+rewrite {
+	activeRecipe(
+			"tech.picnic.errorprone.refasterrules.StringRulesRecipes",
+			//"org.openrewrite.gradle.GradleBestPractices",
+			//"org.openrewrite.java.OrderImports",
+			//"org.openrewrite.java.RemoveUnusedImports",
+			//"org.openrewrite.java.format.RemoveTrailingWhitespace",
+			//"org.openrewrite.java.migrate.UpgradeToJava17",
+			//"org.openrewrite.java.migrate.util.MigrateCollectionsSingletonList",
+			//"org.openrewrite.java.migrate.util.MigrateCollectionsUnmodifiableList",
+			//"org.openrewrite.java.recipes.JavaRecipeBestPractices",
+			//"org.openrewrite.java.recipes.RecipeNullabilityBestPractices",
+			//"org.openrewrite.java.recipes.RecipeTestingBestPractices",
+			//"org.openrewrite.staticanalysis.CodeCleanup",
+			//"org.openrewrite.staticanalysis.EmptyBlock",
+			//"org.openrewrite.staticanalysis.EqualsAvoidsNull",
+			//"org.openrewrite.staticanalysis.JavaApiBestPractices",
+			//"org.openrewrite.staticanalysis.MissingOverrideAnnotation",
+			//"org.openrewrite.staticanalysis.ModifierOrder",
+			//"org.openrewrite.staticanalysis.NoFinalizer",
+			//"org.openrewrite.staticanalysis.RemoveCallsToSystemGc",
+			//"org.openrewrite.staticanalysis.RemoveUnneededAssertion",
+			//"org.openrewrite.staticanalysis.RemoveUnusedLocalVariables",
+			//"org.openrewrite.staticanalysis.RemoveUnusedPrivateFields",
+			//"org.openrewrite.staticanalysis.RemoveUnusedPrivateMethods",
+			//"org.openrewrite.staticanalysis.StringLiteralEquality",
+			//"org.openrewrite.staticanalysis.UnnecessaryParentheses",
+			//"org.openrewrite.staticanalysis.UnnecessaryThrows",
+			//"org.openrewrite.text.EndOfLineAtEndOfFile",
+			//"tech.picnic.errorprone.refasterrules.CollectionRulesRecipes",
+			//"tech.picnic.errorprone.refasterrules.FileRulesRecipes",
+			//"tech.picnic.errorprone.refasterrules.NullRulesRecipes",
+			//"tech.picnic.errorprone.refasterrules.StreamRulesRecipes",
+			)
+	// bugs
+	exclusions.add("**package-info.java")
+	exclusions.add("**AJacksonFormatterFunc.java")
+	exclusions.add("**gradle/java-publish.gradle")
+	failOnDryRunResults = true
+}
+
+// off switch for release: ' -x check' or ' -x rewriteDryRun'
+//tasks {
+//	check.dependsOn(rewriteDryRun)
+//}
+
+// > Task :rewriteDryRun FAILED
+//
+//2 problems were found storing the configuration cache.
+//- Task `:rewriteDryRun` of type `org.openrewrite.gradle.RewriteDryRunTask`: cannot serialize object of type 'org.gradle.api.internal.project.DefaultProject', a subtype of 'org.gradle.api.Project', as these are not supported with the configuration cache.
+//  See https://docs.gradle.org/8.14.3/userguide/configuration_cache.html#config_cache:requirements:disallowed_types
+//- Task `:rewriteDryRun` of type `org.openrewrite.gradle.RewriteDryRunTask`: invocation of 'Task.project' at execution time is unsupported.
+//  See https://docs.gradle.org/8.14.3/userguide/configuration_cache.html#config_cache:requirements:use_project_during_execution
+
+// FAILURE: Build failed with an exception.
+//
+//* What went wrong:
+//Execution failed for task ':rewriteDryRun'.
+//> java.lang.RuntimeException: Applying recipes would make changes. See logs for more details.

gradle/spotless.gradle

@@ -1,33 +1,38 @@
 apply plugin: 'com.diffplug.spotless'
+
 spotless {
+	groovyGradle {
+		target '*.gradle', 'gradle/*.gradle'
+		greclipse().configFile rootProject.files('gradle/spotless.eclipseformat.xml', 'gradle/spotless.groovyformat.prefs')
+	}
+	format 'dotfiles', {
+		target '.gitignore', '.gitattributes', '.editorconfig'
+		leadingTabsToSpaces(2)
+		trimTrailingWhitespace()
+		endWithNewline()
+	}
 	def noInternalDepsClosure = {
 		String text = it
 		/*
 		 * No good way to get around using this import:
 		 * https://github.com/gradle/gradle/issues/3191
 		 */
 		String regex = "import org\\.gradle\\.api\\.internal\\.(?!plugins\\.DslObject)(?!project\\.ProjectInternal)"
-		if ((text.contains('import org.gradle.internal.') || text.find(regex)) &&
-				!text.contains('def noInternalDepsClosure')) {
+		if ((text.contains('import org.gradle.internal.') || text.find(regex))
+				&& !text.contains('def noInternalDepsClosure')) {
 			throw new AssertionError("Accidental internal import")
 		}
 	}
-	if (project != rootProject) {
-		// the rootProject doesn't have any java
-		java {
-			ratchetFrom 'origin/main'
-			bumpThisNumberIfACustomStepChanges(1)
-			licenseHeaderFile rootProject.file('gradle/spotless.license')
-			importOrderFile   rootProject.file('gradle/spotless.importorder')
-			eclipse().configFile rootProject.file('gradle/spotless.eclipseformat.xml')
-			trimTrailingWhitespace()
-			removeUnusedImports()
-			formatAnnotations()
-			custom 'noInternalDeps', noInternalDepsClosure
-		}
-	}
-	groovyGradle {
-		target '*.gradle'
-		greclipse().configFile rootProject.files('gradle/spotless.eclipseformat.xml', 'gradle/spotless.groovyformat.prefs')
+	java {
+		target '*.gitignore'
+		ratchetFrom 'origin/main'
+		bumpThisNumberIfACustomStepChanges(1)
+		licenseHeaderFile rootProject.file('gradle/spotless.license')
+		importOrderFile   rootProject.file('gradle/spotless.importorder')
+		eclipse().configFile rootProject.file('gradle/spotless.eclipseformat.xml')
+		trimTrailingWhitespace()
+		removeUnusedImports()
+		formatAnnotations()
+		custom 'noInternalDeps', noInternalDepsClosure
 	}
 }

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

@@ -128,7 +128,7 @@ private static JarState provisionWithTransitives(boolean withTransitives, Collec
 		Objects.requireNonNull(provisioner, "provisioner");
 		Set<File> jars = provisioner.provisionWithTransitives(withTransitives, mavenCoordinates);
 		if (jars.isEmpty()) {
-			throw new NoSuchElementException("Resolved to an empty result: " + mavenCoordinates.stream().collect(Collectors.joining(", ")));
+			throw new NoSuchElementException("Resolved to an empty result: " + String.join(", ", mavenCoordinates));
 		}
 		FileSignature fileSignature = FileSignature.signAsSet(jars);
 		return new JarState(fileSignature);

lib/src/main/java/com/diffplug/spotless/npm/PrettierFormatterStep.java

@@ -137,7 +137,7 @@ private String assertFilepathInConfigOptions(File file) {
 				return prettierConfigOptions;
 			}
 			// if the file has no name, we  cannot use it
-			if (file.getName().trim().length() == 0) {
+			if (file.getName().trim().isEmpty()) {
 				return prettierConfigOptions;
 			}
 			// if it is not there, we add it at the beginning of the Options

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

@@ -15,6 +15,7 @@
  */
 package com.diffplug.gradle.spotless;
 
+import static com.diffplug.common.base.Strings.isNullOrEmpty;
 import static org.junit.jupiter.api.Assertions.fail;
 
 import java.io.File;
@@ -231,7 +232,7 @@ static String buildResultToString(BuildResult result) {
 
 	private static File getTestKitDir() {
 		String gradleUserHome = System.getenv("GRADLE_USER_HOME");
-		if (gradleUserHome == null || gradleUserHome.isEmpty()) {
+		if (isNullOrEmpty(gradleUserHome)) {
 			gradleUserHome = new File(System.getProperty("user.home"), ".gradle").getAbsolutePath();
 		}
 		return new File(gradleUserHome, "testkit");

plugin-maven/src/main/java/com/diffplug/spotless/maven/AbstractSpotlessMojo.java

@@ -15,6 +15,7 @@
  */
 package com.diffplug.spotless.maven;
 
+import static com.diffplug.common.base.Strings.isNullOrEmpty;
 import static java.util.stream.Collectors.toList;
 
 import java.io.File;
@@ -290,7 +291,7 @@ private List<File> collectFiles(FormatterFactory formatterFactory, FormatterConf
 			} else {
 				files = collectFilesFromFormatterFactory(formatterFactory);
 			}
-			if (filePatterns == null || filePatterns.isEmpty()) {
+			if (isNullOrEmpty(filePatterns)) {
 				return files;
 			}
 			final String[] includePatterns = this.filePatterns.split(",");

plugin-maven/src/main/java/com/diffplug/spotless/maven/SpotlessApplyMojo.java

@@ -18,6 +18,8 @@
 import java.io.File;
 import java.io.IOException;
 
+import com.diffplug.common.base.Strings;
+
 import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugins.annotations.Mojo;
 import org.apache.maven.plugins.annotations.Parameter;
@@ -26,6 +28,8 @@
 import com.diffplug.spotless.Formatter;
 import com.diffplug.spotless.maven.incremental.UpToDateChecker;
 
+import static com.diffplug.common.base.Strings.isNullOrEmpty;
+
 /**
  * Performs formatting of all source files according to configured formatters.
  */
@@ -86,6 +90,6 @@ protected void process(String name, Iterable<File> files, Formatter formatter, U
 	}
 
 	private boolean isIdeHook() {
-		return !(spotlessIdeHook == null || spotlessIdeHook.isEmpty());
+		return !isNullOrEmpty(spotlessIdeHook);
 	}
 }