[Experimental] Add rewrite support for RemoveUnusedPrivateMethods & RemoveUnusedImports

Author: Vincent Potucek

README.md

@@ -201,7 +201,12 @@ For experiments (or regression testing purposes) add `-PcheckstyleVersion=X.y.z`
 #### Spotless ####
 The import order is a part of static check. please call `spotlessApply` to optimize the imports of Java codes before filing pull request.
 
-    ./gradlew spotlessApply
+`./gradlew spotlessApply`
+
+#### Rewrite ####
+The import order is a part of static check. please call `rewriteRun` to optimize the imports of Java codes before filing pull request.
+
+`./gradlew rewriteRun`
 
 #### Spotbugs ####
 Spotbugs uses static analysis to look for bugs in the code.

build.gradle

@@ -16,6 +16,11 @@
 import org.ajoberstar.grgit.Grgit
 import java.nio.charset.StandardCharsets
 
+import static java.lang.Boolean.valueOf
+import static java.lang.System.getenv
+import static java.lang.System.getenv
+import static java.util.Objects.isNull
+
 buildscript {
   repositories {
     mavenCentral()
@@ -29,18 +34,77 @@ buildscript {
 }
 
 plugins {
-  id 'com.github.ben-manes.versions' version '0.48.0'
-  id 'idea'
-  id 'jacoco'
-  id 'java-library'
-  id 'org.owasp.dependencycheck' version '8.2.1'
-  id 'org.nosphere.apache.rat' version "0.8.1"
+  id "com.diffplug.spotless" version "7.2.1"
+  id "com.github.ben-manes.versions" version "0.48.0"
+  id "com.github.spotbugs" version "6.0.25" apply false
+  id "com.gradleup.shadow" version "8.3.6" apply false
+  id "idea"
   id "io.swagger.core.v3.swagger-gradle-plugin" version "${swaggerVersion}"
+  id "jacoco"
+  id "java-library"
+  id "org.nosphere.apache.rat" version "0.8.1"
+  id "org.openrewrite.rewrite" version "7.12.1"
+  id "org.owasp.dependencycheck" version "8.2.1"
+  id "org.scoverage" version "8.0.3" apply false
+}
+
+rewrite {
+  activeRecipe(
+          "org.openrewrite.gradle.GradleBestPractices",
+          "org.openrewrite.java.RemoveUnusedImports",
+          "org.openrewrite.staticanalysis.RemoveUnusedLocalVariables",
+          "org.openrewrite.staticanalysis.RemoveUnusedPrivateFields",
+          "org.openrewrite.staticanalysis.RemoveUnusedPrivateMethods",
+          //"org.openrewrite.java.OrderImports",
+          //"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.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.NullRulesRecipes",
+          //"tech.picnic.errorprone.refasterrules.StreamRulesRecipes",
+          //"tech.picnic.errorprone.refasterrules.StringRulesRecipes",
+          // running active recipes: tech.picnic.errorprone.refasterrules.NullRulesRecipes
+          //<============-> 99% EXECUTING [1h 38s]
+          //> :rewriteRun
+  )
+  exportDatatables = true
+  exclusions.add("**.GarbageCollectedMemoryPoolTest.java")
+  failOnDryRunResults = true
+}
 
-  id "com.github.spotbugs" version '6.0.25' apply false
-  id 'org.scoverage' version '8.0.3' apply false
-  id 'com.gradleup.shadow' version '8.3.6' apply false
-  id 'com.diffplug.spotless' version "6.25.0"
+spotless {
+  java {
+    targetExclude('**/generated/**/*.java','**/generated-test/**/*.java')
+    importOrder('kafka', 'org.apache.kafka', 'com', 'net', 'org', 'java', 'javax', '', '\\#')
+    //licenseHeaderFile("$rootDir/checkstyle/java.header", 'package') todo apply me
+  }
+  scala {
+    scalafmt("$versions.scalafmt").configFile("$rootDir/checkstyle/.scalafmt.conf").scalaMajorVersion(versions.baseScala)
+    //licenseHeaderFile("$rootDir/checkstyle/java.header", 'package') todo apply me
+  }
+}
+
+dependencies {
+  rewrite("org.openrewrite.recipe:rewrite-third-party:0.24.3", "org.openrewrite.recipe:rewrite-static-analysis:2.13.0")
 }
 
 ext {
@@ -157,7 +221,7 @@ ext {
     libs.log4j2Api,
     libs.log4j2Core
   ]
-  
+
 }
 
 allprojects {
@@ -224,6 +288,11 @@ allprojects {
     delete "${projectDir}/src/generated"
     delete "${projectDir}/src/generated-test"
   }
+
+  // off switch for release: ' -x check' or ' -x rewriteDryRun spotlessJavaCheck'
+  tasks {
+    check.dependsOn(rewriteDryRun, spotlessCheck)
+  }
 }
 
 def determineCommitId() {
@@ -551,7 +620,7 @@ subprojects {
         maxFailures = userMaxTestRetryFailures
       }
     }
-    
+
     finalizedBy("copyTestXml")
   }
 
@@ -816,14 +885,6 @@ subprojects {
     skipProjects = [ ":jmh-benchmarks", ":trogdor" ]
     skipConfigurations = [ "zinc" ]
   }
-  apply plugin: 'com.diffplug.spotless'
-  spotless {
-    java {
-      targetExclude('**/generated/**/*.java','**/generated-test/**/*.java')
-      importOrder('kafka', 'org.apache.kafka', 'com', 'net', 'org', 'java', 'javax', '', '\\#')
-      removeUnusedImports()
-    }
-  }
 }
 
 gradle.taskGraph.whenReady { taskGraph ->
@@ -2811,15 +2872,6 @@ project(':streams:streams-scala') {
   jar {
     dependsOn 'copyDependantLibs'
   }
-
-  apply plugin: 'com.diffplug.spotless'
-  spotless {
-    scala {
-      target '**/*.scala'
-      scalafmt("$versions.scalafmt").configFile('../../checkstyle/.scalafmt.conf').scalaMajorVersion(versions.baseScala)
-      licenseHeaderFile '../../checkstyle/java.header', 'package'
-    }
-  }
 }
 
 project(':streams:integration-tests') {

clients/clients-integration-tests/src/test/java/org/apache/kafka/clients/consumer/ConsumerTopicCreationTest.java

@@ -19,18 +19,15 @@
 import org.apache.kafka.clients.admin.Admin;
 import org.apache.kafka.clients.admin.TopicListing;
 import org.apache.kafka.common.test.ClusterInstance;
-import org.apache.kafka.common.test.api.ClusterConfig;
 import org.apache.kafka.common.test.api.ClusterTemplate;
 
 import java.time.Duration;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
-import java.util.Set;
 
 import static org.apache.kafka.clients.consumer.ConsumerConfig.ALLOW_AUTO_CREATE_TOPICS_CONFIG;
 import static org.apache.kafka.clients.consumer.ConsumerConfig.GROUP_PROTOCOL_CONFIG;
-import static org.apache.kafka.common.test.api.Type.KRAFT;
 import static org.apache.kafka.server.config.ServerLogConfigs.AUTO_CREATE_TOPICS_ENABLE_CONFIG;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -102,19 +99,6 @@ private List<String> getAllTopics(ClusterInstance cluster) throws Exception {
         }
     }
 
-    private static List<ClusterConfig> autoCreateTopicsConfigs() {
-        return List.of(
-            ClusterConfig.defaultBuilder()
-                .setTypes(Set.of(KRAFT))
-                .setServerProperties(Map.of(AUTO_CREATE_TOPICS_ENABLE_CONFIG, "true"))
-                .build(),
-            ClusterConfig.defaultBuilder()
-                .setTypes(Set.of(KRAFT))
-                .setServerProperties(Map.of(AUTO_CREATE_TOPICS_ENABLE_CONFIG, "false"))
-                .build()
-        );
-    }
-
     private Consumer<byte[], byte[]> createConsumer(ClusterInstance cluster, GroupProtocol protocol, boolean allowConsumerAutoCreateTopics) {
         Map<String, Object> consumerConfig = Map.of(
             ALLOW_AUTO_CREATE_TOPICS_CONFIG, allowConsumerAutoCreateTopics,

clients/src/main/java/org/apache/kafka/common/requests/ShareAcknowledgeResponse.java

@@ -88,12 +88,6 @@ public static ShareAcknowledgeResponse parse(Readable readable, short version) {
         );
     }
 
-    private static boolean matchingTopic(ShareAcknowledgeResponseData.ShareAcknowledgeTopicResponse previousTopic, TopicIdPartition currentTopic) {
-        if (previousTopic == null)
-            return false;
-        return previousTopic.topicId().equals(currentTopic.topicId());
-    }
-
     public static ShareAcknowledgeResponseData.PartitionData partitionResponse(TopicIdPartition topicIdPartition, Errors error) {
         return partitionResponse(topicIdPartition.topicPartition().partition(), error);
     }

clients/src/test/java/org/apache/kafka/clients/consumer/internals/ConsumerCoordinatorTest.java

@@ -149,7 +149,6 @@ public abstract class ConsumerCoordinatorTest {
     private final long retryBackoffMaxMs = 1000;
     private final int autoCommitIntervalMs = 2000;
     private final int requestTimeoutMs = 30000;
-    private final int throttleMs = 10;
     private final MockTime time = new MockTime();
     private GroupRebalanceConfig rebalanceConfig;
 

clients/src/test/java/org/apache/kafka/common/security/oauthbearer/internals/secured/assertion/DefaultAssertionCreatorTest.java

@@ -19,7 +19,6 @@
 import org.apache.kafka.common.KafkaException;
 import org.apache.kafka.common.security.oauthbearer.internals.secured.OAuthBearerTest;
 import org.apache.kafka.common.utils.MockTime;
-import org.apache.kafka.common.utils.Time;
 
 import org.jose4j.jwt.consumer.JwtContext;
 import org.jose4j.jwx.JsonWebStructure;
@@ -165,8 +164,6 @@ public void testInvalidAlgorithm() throws IOException {
     }
 
     private static class Builder {
-
-        private final Time time = new MockTime();
         private String algorithm = TOKEN_SIGNING_ALGORITHM_RS256;
         private File privateKeyFile;
         private Optional<String> passphrase = Optional.empty();

connect/runtime/src/test/java/org/apache/kafka/connect/runtime/WorkerTest.java

@@ -2977,11 +2977,6 @@ private void verifyConverters() {
         verify(plugins).newInternalConverter(eq(false), anyString(), anyMap());
     }
 
-    private void mockTaskConverter(ClassLoaderUsage classLoaderUsage, String converterClassConfig, Converter returning) {
-        when(plugins.newConverter(any(AbstractConfig.class), eq(converterClassConfig), eq(classLoaderUsage)))
-                       .thenReturn(returning);
-    }
-
     private void mockVersionedTaskConverterFromConnector(String converterClassConfig, String converterVersionConfig, Converter returning) {
         when(plugins.newConverter(any(ConnectorConfig.class), eq(converterClassConfig), eq(converterVersionConfig))).thenReturn(returning);
     }
@@ -2998,15 +2993,6 @@ private void verifyVersionedTaskConverterFromWorker(String converterClassConfig,
         verify(plugins).newConverter(any(WorkerConfig.class), eq(converterClassConfig), eq(converterVersionConfig));
     }
 
-    private void mockTaskHeaderConverter(ClassLoaderUsage classLoaderUsage, HeaderConverter returning) {
-        when(plugins.newHeaderConverter(any(AbstractConfig.class), eq(WorkerConfig.HEADER_CONVERTER_CLASS_CONFIG), eq(classLoaderUsage)))
-               .thenReturn(returning);
-    }
-
-    private void verifyTaskHeaderConverter() {
-        verify(plugins).newHeaderConverter(any(AbstractConfig.class), eq(WorkerConfig.HEADER_CONVERTER_CLASS_CONFIG), eq(ClassLoaderUsage.CURRENT_CLASSLOADER));
-    }
-
     private void mockVersionedTaskHeaderConverterFromConnector(HeaderConverter returning) {
         when(plugins.newHeaderConverter(any(ConnectorConfig.class), eq(ConnectorConfig.HEADER_CONVERTER_CLASS_CONFIG), eq(ConnectorConfig.HEADER_CONVERTER_VERSION_CONFIG)))
                .thenReturn(returning);
@@ -3034,25 +3020,13 @@ private void verifyGenericIsolation() {
         verify(loaderSwap, atLeastOnce()).close();
     }
 
-    private void mockConnectorIsolation(String connectorClass, Connector connector) {
-        mockGenericIsolation();
-        when(plugins.newConnector(connectorClass)).thenReturn(connector);
-        when(connector.version()).thenReturn("1.0");
-    }
-
     private void mockVersionedConnectorIsolation(String connectorClass, VersionRange range, Connector connector) {
         mockGenericIsolation();
         when(plugins.pluginLoader(connectorClass, range)).thenReturn(pluginLoader);
         when(plugins.newConnector(connectorClass, range)).thenReturn(connector);
         when(connector.version()).thenReturn(range == null ? "unknown" : range.toString());
     }
 
-    private void verifyConnectorIsolation(Connector connector) {
-        verifyGenericIsolation();
-        verify(plugins).newConnector(anyString());
-        verify(connector, atLeastOnce()).version();
-    }
-
     private void verifyVersionedConnectorIsolation(String connectorClass, VersionRange range, Connector connector) {
         verifyGenericIsolation();
         verify(plugins).pluginLoader(connectorClass, range);
@@ -3077,13 +3051,6 @@ private void mockVersionedTaskIsolation(Class<? extends Connector> connectorClas
         when(task.version()).thenReturn(range == null ? "unknown" : range.toString());
     }
 
-    private void verifyTaskIsolation(Task task) {
-        verifyGenericIsolation();
-        verify(plugins).connectorClass(anyString());
-        verify(plugins).newTask(any());
-        verify(task).version();
-    }
-
     private void verifyVersionedTaskIsolation(Class<? extends Connector> connectorClass, Class<? extends Task> taskClass, VersionRange range, Task task) {
         verifyGenericIsolation();
         verify(plugins).pluginLoader(connectorClass.getName(), range);

connect/runtime/src/test/resources/test-plugins/bad-packaging/test/plugins/StaticInitializerThrowsRestExtension.java

@@ -18,14 +18,10 @@
 package test.plugins;
 
 import java.io.IOException;
-import java.util.List;
 import java.util.Map;
 
-import org.apache.kafka.common.config.ConfigDef;
-import org.apache.kafka.connect.connector.Task;
 import org.apache.kafka.connect.rest.ConnectRestExtension;
 import org.apache.kafka.connect.rest.ConnectRestExtensionContext;
-import org.apache.kafka.connect.sink.SinkConnector;
 
 /**
  * Fake plugin class for testing classloading isolation.

connect/runtime/src/test/resources/test-plugins/classpath-converter/org/apache/kafka/connect/converters/ByteArrayConverter.java

@@ -19,17 +19,14 @@
 import org.apache.kafka.common.config.ConfigDef;
 import org.apache.kafka.common.utils.AppInfoParser;
 import org.apache.kafka.connect.components.Versioned;
-import org.apache.kafka.connect.connector.Task;
 import org.apache.kafka.connect.data.Schema;
 import org.apache.kafka.connect.data.SchemaAndValue;
 import org.apache.kafka.connect.errors.DataException;
-import org.apache.kafka.connect.sink.SinkConnector;
 import org.apache.kafka.connect.storage.Converter;
 import org.apache.kafka.connect.storage.ConverterConfig;
 import org.apache.kafka.connect.storage.HeaderConverter;
 
 import java.nio.ByteBuffer;
-import java.util.List;
 import java.util.Map;
 
 public class ByteArrayConverter implements Converter, HeaderConverter, Versioned {

connect/runtime/src/test/resources/test-plugins/sampling-config-provider/test/plugins/SamplingConfigProvider.java

@@ -27,11 +27,7 @@
 import org.apache.kafka.common.config.provider.ConfigProvider;
 import org.apache.kafka.common.config.ConfigData;
 import org.apache.kafka.common.config.ConfigChangeCallback;
-import org.apache.kafka.connect.data.Schema;
-import org.apache.kafka.connect.data.SchemaAndValue;
-import org.apache.kafka.connect.storage.Converter;
 import org.apache.kafka.connect.runtime.isolation.SamplingTestPlugin;
-import org.apache.kafka.connect.storage.HeaderConverter;
 
 /**
  * Fake plugin class for testing classloading isolation.