[Experimental] Add rewrite support for RemoveUnusedPrivateMethods & RemoveUnusedImports

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 rewriteDryRun
       - name: build (everything-but-maven)
         if: matrix.kind == 'gradle'
-        run: ./gradlew build -x spotlessCheck -PSPOTLESS_EXCLUDE_MAVEN=true
+        run: ./gradlew build -x spotlessCheck 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

@@ -1,20 +1,19 @@
 apply plugin: 'dev.equo.ide'
-equoIde {
-	branding().title('Spotless').icon(file('_images/spotless_logo.png'))
-	welcome().openUrl('https://github.com/diffplug/spotless/blob/main/CONTRIBUTING.md')
-	gradleBuildship().autoImport('.')
-}
 
-repositories {
-	mavenCentral()
-}
-
-apply from: rootProject.file('gradle/java-publish.gradle')
 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')
+	gradleBuildship().autoImport('.')
 }
-apply from: rootProject.file('gradle/spotless-freshmark.gradle')
 
 spotless {
 	groovyGradle {
@@ -27,3 +26,11 @@ spotless {
 		endWithNewline()
 	}
 }
+
+repositories {
+	mavenCentral()
+}
+
+dependencies {
+	rewrite("org.openrewrite.recipe:rewrite-static-analysis:2.12.0")
+}

gradle/rewrite.gradle

@@ -0,0 +1,17 @@
+apply plugin: 'org.openrewrite.rewrite'
+
+rewrite {
+	//activeRecipe("org.openrewrite.java.RemoveUnusedImports") bug
+	//activeRecipe("org.openrewrite.staticanalysis.RemoveUnusedLocalVariables") bug
+	activeRecipe("org.openrewrite.gradle.GradleBestPractices")
+	activeRecipe("org.openrewrite.staticanalysis.RemoveUnusedPrivateFields")
+	activeRecipe("org.openrewrite.staticanalysis.RemoveUnusedPrivateMethods")
+	failOnDryRunResults = true
+}
+
+//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
+//

lib-extra/src/test/java/com/diffplug/spotless/extra/eclipse/EclipseResourceHarness.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2024 DiffPlug
+ * Copyright 2016-2025 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,8 +15,6 @@
  */
 package com.diffplug.spotless.extra.eclipse;
 
-import static org.assertj.core.api.Assertions.*;
-
 import java.io.File;
 import java.util.Arrays;
 

lib-extra/src/test/java/com/diffplug/spotless/extra/groovy/GrEclipseFormatterStepTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2024 DiffPlug
+ * Copyright 2016-2025 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,8 +24,6 @@
 import com.diffplug.spotless.extra.eclipse.EquoResourceHarness;
 
 public class GrEclipseFormatterStepTest extends EquoResourceHarness {
-	private final static String INPUT = "class F{ def m(){} }";
-	private final static String EXPECTED = "class F{\n\tdef m(){}\n}";
 
 	public GrEclipseFormatterStepTest() {
 		super(GrEclipseFormatterStep.createBuilder(TestProvisioner.mavenCentral()));

lib/src/compatKtLint0Dot49Dot0/java/com/diffplug/spotless/glue/ktlint/compat/KtLintCompat0Dot49Dot0Adapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023-2024 DiffPlug
+ * Copyright 2023-2025 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,9 +27,6 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import com.pinterest.ktlint.cli.ruleset.core.api.RuleSetProviderV3;
 import com.pinterest.ktlint.rule.engine.api.Code;
 import com.pinterest.ktlint.rule.engine.api.EditorConfigDefaults;
@@ -55,8 +52,6 @@
 
 public class KtLintCompat0Dot49Dot0Adapter implements KtLintCompatAdapter {
 
-	private static final Logger logger = LoggerFactory.getLogger(KtLintCompat0Dot49Dot0Adapter.class);
-
 	private static final List<EditorConfigProperty<?>> DEFAULT_EDITOR_CONFIG_PROPERTIES;
 
 	static {

lib/src/compatKtLint0Dot50Dot0/java/com/diffplug/spotless/glue/ktlint/compat/KtLintCompat0Dot50Dot0Adapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023-2024 DiffPlug
+ * Copyright 2023-2025 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,9 +25,6 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import com.pinterest.ktlint.cli.ruleset.core.api.RuleSetProviderV3;
 import com.pinterest.ktlint.rule.engine.api.Code;
 import com.pinterest.ktlint.rule.engine.api.EditorConfigDefaults;
@@ -55,8 +52,6 @@
 
 public class KtLintCompat0Dot50Dot0Adapter implements KtLintCompatAdapter {
 
-	private static final Logger logger = LoggerFactory.getLogger(KtLintCompat0Dot50Dot0Adapter.class);
-
 	private static final List<EditorConfigProperty<?>> DEFAULT_EDITOR_CONFIG_PROPERTIES;
 
 	static {

lib/src/compatKtLint1Dot0Dot0/java/com/diffplug/spotless/glue/ktlint/compat/KtLintCompat1Dot0Dot0Adapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023-2024 DiffPlug
+ * Copyright 2023-2025 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,9 +24,6 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import com.pinterest.ktlint.cli.ruleset.core.api.RuleSetProviderV3;
 import com.pinterest.ktlint.rule.engine.api.Code;
 import com.pinterest.ktlint.rule.engine.api.EditorConfigDefaults;
@@ -54,8 +51,6 @@
 
 public class KtLintCompat1Dot0Dot0Adapter implements KtLintCompatAdapter {
 
-	private static final Logger logger = LoggerFactory.getLogger(KtLintCompat1Dot0Dot0Adapter.class);
-
 	private static final List<EditorConfigProperty<?>> DEFAULT_EDITOR_CONFIG_PROPERTIES;
 
 	static {

lib/src/gherkin/java/com/diffplug/spotless/glue/gherkin/GherkinUtilsFormatterFunc.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023 DiffPlug
+ * Copyright 2023-2025 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,11 +15,7 @@
  */
 package com.diffplug.spotless.glue.gherkin;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import com.diffplug.spotless.FormatterFunc;
-import com.diffplug.spotless.gherkin.GherkinUtilsConfig;
 
 import io.cucumber.gherkin.GherkinParser;
 import io.cucumber.gherkin.utils.pretty.Pretty;
@@ -30,13 +26,6 @@
 import io.cucumber.messages.types.SourceMediaType;
 
 public class GherkinUtilsFormatterFunc implements FormatterFunc {
-	private static final Logger LOGGER = LoggerFactory.getLogger(GherkinUtilsFormatterFunc.class);
-
-	private final GherkinUtilsConfig gherkinSimpleConfig;
-
-	public GherkinUtilsFormatterFunc(GherkinUtilsConfig gherkinSimpleConfig) {
-		this.gherkinSimpleConfig = gherkinSimpleConfig;
-	}
 
 	// Follows https://github.com/cucumber/gherkin-utils/blob/main/java/src/test/java/io/cucumber/gherkin/utils/pretty/PrettyTest.java
 	private GherkinDocument parse(String gherkin) {