Add error-prone.picnic.tech featuring ConstantNaming

Author: Vincent Potucek

build.gradle

@@ -12,6 +12,7 @@ repositories {
 apply from: rootProject.file('gradle/java-publish.gradle')
 apply from: rootProject.file('gradle/changelog.gradle')
 allprojects {
+	apply from: rootProject.file('gradle/error-prone.gradle')
 	apply from: rootProject.file('gradle/rewrite.gradle')
 	apply from: rootProject.file('gradle/spotless.gradle')
 }

gradle/error-prone.gradle

@@ -0,0 +1,75 @@
+import static java.lang.System.getenv
+
+apply plugin: 'net.ltgt.errorprone'
+
+dependencies {
+	errorprone('com.google.errorprone:error_prone_core:2.42.0')
+	errorprone('tech.picnic.error-prone-support:error-prone-contrib:0.25.0')
+	errorprone('tech.picnic.error-prone-support:refaster-runner:0.25.0')
+	constraints {
+		errorprone('com.google.guava:guava') {
+			version {
+				require('33.4.8-jre')
+			}
+			because('Older versions use deprecated methods in sun.misc.Unsafe')
+			// https://github.com/junit-team/junit-framework/pull/5039#discussion_r2414490581
+		}
+	}
+}
+
+tasks.withType(JavaCompile).configureEach {
+	options.errorprone {
+		allErrorsAsWarnings = true // ModuleHelper.java:37: warning: Unsafe is internal proprietary API and may be removed in a future release
+		errorproneArgs.add('-XepOpt:Refaster:NamePattern=^(?!.*Rules\\$).*')
+		error(
+				'ConstantNaming',
+				'DirectReturn',
+				// 'EmptyMethod',
+				// 'EmptyMonoZip',
+				// 'LexicographicalAnnotationAttributeListing',
+				// 'LexicographicalAnnotationListing',
+				// 'MissingOverride',
+				// 'MissingTestCall',
+				// 'NonEmptyMono',
+				// 'NonStaticImport',
+				// 'OptionalMapUnusedValue',
+				// 'OptionalOfRedundantMethod',
+				// 'RedundantSetterCall',
+				// 'RedundantStringConversion',
+				// 'RedundantStringEscape',
+				// 'StaticImport',
+				// 'StringJoin',
+				// 'UnnecessaryCheckNotNull',
+				// 'UnnecessaryTypeArgument',
+				// 'UnusedAnonymousClass',
+				// 'UnusedCollectionModifiedInPlace',
+				)
+		if (!getenv().containsKey('CI') && getenv('IN_PLACE')?.toBoolean()) {
+			errorproneArgs.addAll(
+					'-XepPatchLocation:IN_PLACE',
+					'-XepPatchChecks:' +
+					'ConstantNaming,' +
+					'DirectReturn,'
+					// 'MissingOverride,' +
+					// 'StaticImport,' +
+					// EmptyMethod,' +
+					// EmptyMonoZip,' +
+					// LexicographicalAnnotationAttributeListing,' +
+					// LexicographicalAnnotationListing,' +
+					// MissingTestCall,' +
+					// NonEmptyMono,' +
+					// NonStaticImport,' +
+					// OptionalMapUnusedValue,' +
+					// OptionalOfRedundantMethod,' +
+					// RedundantSetterCall,' +
+					// RedundantStringConversion,' +
+					// RedundantStringEscape,' +
+					// StringJoin,' +
+					// UnnecessaryCheckNotNull,' +
+					// UnnecessaryTypeArgument,' +
+					// UnusedAnonymousClass,' +
+					// UnusedCollectionModifiedInPlace,'
+					)
+		}
+	}
+}

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.
@@ -55,7 +55,7 @@
 
 public class KtLintCompat0Dot49Dot0Adapter implements KtLintCompatAdapter {
 
-	private static final Logger logger = LoggerFactory.getLogger(KtLintCompat0Dot49Dot0Adapter.class);
+	private static final Logger LOGGER = LoggerFactory.getLogger(KtLintCompat0Dot49Dot0Adapter.class);
 
 	private static final List<EditorConfigProperty<?>> DEFAULT_EDITOR_CONFIG_PROPERTIES;
 

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.
@@ -55,7 +55,7 @@
 
 public class KtLintCompat0Dot50Dot0Adapter implements KtLintCompatAdapter {
 
-	private static final Logger logger = LoggerFactory.getLogger(KtLintCompat0Dot50Dot0Adapter.class);
+	private static final Logger LOGGER = LoggerFactory.getLogger(KtLintCompat0Dot50Dot0Adapter.class);
 
 	private static final List<EditorConfigProperty<?>> DEFAULT_EDITOR_CONFIG_PROPERTIES;
 

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.
@@ -54,7 +54,7 @@
 
 public class KtLintCompat1Dot0Dot0Adapter implements KtLintCompatAdapter {
 
-	private static final Logger logger = LoggerFactory.getLogger(KtLintCompat1Dot0Dot0Adapter.class);
+	private static final Logger LOGGER = LoggerFactory.getLogger(KtLintCompat1Dot0Dot0Adapter.class);
 
 	private static final List<EditorConfigProperty<?>> DEFAULT_EDITOR_CONFIG_PROPERTIES;
 

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

@@ -146,11 +146,11 @@ public File getOnlyFile() {
 		}
 	}
 
-	private static final boolean machineIsWin = System.getProperty("os.name").toLowerCase(Locale.ROOT).contains("win");
+	private static final boolean MACHINE_IS_WIN = System.getProperty("os.name").toLowerCase(Locale.ROOT).contains("win");
 
 	/** Returns true if this JVM is running on a windows machine. */
 	public static boolean machineIsWin() {
-		return machineIsWin;
+		return MACHINE_IS_WIN;
 	}
 
 	/** Transforms a native path to a unix one. */

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

@@ -143,13 +143,13 @@ static void legacyErrorBehavior(Formatter formatter, File file, ValuePerStep<Thr
 		for (int i = 0; i < formatter.getSteps().size(); i++) {
 			Throwable exception = exceptionPerStep.get(i);
 			if (exception != null && exception != LintState.formatStepCausedNoChange()) {
-				logger.error("Step '{}' found problem in '{}':\n{}", formatter.getSteps().get(i).getName(), file.getName(), exception.getMessage(), exception);
+				LOGGER.error("Step '{}' found problem in '{}':\n{}", formatter.getSteps().get(i).getName(), file.getName(), exception.getMessage(), exception);
 				throw ThrowingEx.asRuntimeRethrowError(exception);
 			}
 		}
 	}
 
-	private static final Logger logger = LoggerFactory.getLogger(Formatter.class);
+	private static final Logger LOGGER = LoggerFactory.getLogger(Formatter.class);
 
 	/**
 	 * Returns the result of calling all of the FormatterSteps, while also

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

@@ -45,15 +45,15 @@
  */
 public final class JarState implements Serializable {
 
-	private static final Logger logger = LoggerFactory.getLogger(JarState.class);
+	private static final Logger LOGGER = LoggerFactory.getLogger(JarState.class);
 
 	// Let the classloader be overridden for tools using different approaches to classloading
 	@Nullable private static ClassLoader forcedClassLoader;
 
 	/** Overrides the classloader used by all JarStates. */
 	public static void setForcedClassLoader(@Nullable ClassLoader forcedClassLoader) {
 		if (!Objects.equals(JarState.forcedClassLoader, forcedClassLoader)) {
-			logger.info("Overriding the forced classloader for JarState from {} to {}", JarState.forcedClassLoader, forcedClassLoader);
+			LOGGER.info("Overriding the forced classloader for JarState from {} to {}", JarState.forcedClassLoader, forcedClassLoader);
 		}
 		JarState.forcedClassLoader = forcedClassLoader;
 	}

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

@@ -84,7 +84,7 @@ public Policy createPolicy(File projectDir, Supplier<Iterable<File>> toFormat) {
 	/** Should use {@link #createPolicy(File, Supplier)} instead, but this will work iff its a path-independent LineEnding policy. */
 	public Policy createPolicy() {
 		switch (this) {
-		case PLATFORM_NATIVE:	return _platformNativePolicy;
+		case PLATFORM_NATIVE:	return _PLATFORM_NATIVE_POLICY;
 		case WINDOWS:			return WINDOWS_POLICY;
 		case UNIX:				return UNIX_POLICY;
 		case MAC_CLASSIC:		return MAC_CLASSIC_POLICY;
@@ -152,9 +152,9 @@ static String getEndingFor(Reader reader) throws IOException {
 	private static final Policy UNIX_POLICY = new ConstantLineEndingPolicy(UNIX.str());
     private static final Policy MAC_CLASSIC_POLICY = new ConstantLineEndingPolicy(MAC_CLASSIC.str());
     private static final Policy PRESERVE_POLICY = new PreserveLineEndingPolicy();
-	private static final String _platformNative = System.getProperty("line.separator");
-	private static final Policy _platformNativePolicy = new ConstantLineEndingPolicy(_platformNative);
-	private static final boolean nativeIsWin = _platformNative.equals(WINDOWS.str());
+	private static final String _PLATFORM_NATIVE = System.getProperty("line.separator");
+	private static final Policy _PLATFORM_NATIVE_POLICY = new ConstantLineEndingPolicy(_PLATFORM_NATIVE);
+	private static final boolean NATIVE_IS_WIN = _PLATFORM_NATIVE.equals(WINDOWS.str());
 
 	/**
 	 * @deprecated Using the system-native line endings to detect the windows operating system has turned out
@@ -164,13 +164,13 @@ static String getEndingFor(Reader reader) throws IOException {
 	 */
 	@Deprecated
 	public static boolean nativeIsWin() {
-		return nativeIsWin;
+		return NATIVE_IS_WIN;
 	}
 
 	/** Returns the standard line ending for this policy. */
 	public String str() {
 		switch (this) {
-		case PLATFORM_NATIVE:	return _platformNative;
+		case PLATFORM_NATIVE:	return _PLATFORM_NATIVE;
 		case WINDOWS:			return "\r\n";
 		case UNIX:				return "\n";
 		case MAC_CLASSIC:		return "\r";

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

@@ -197,10 +197,10 @@ public static LintState of(Formatter formatter, File file, byte[] rawBytes) {
 
 	/** Returns the DirtyState which corresponds to {@code isClean()}. */
 	public static LintState clean() {
-		return isClean;
+		return IS_CLEAN;
 	}
 
-	private static final LintState isClean = new LintState(DirtyState.clean(), null);
+	private static final LintState IS_CLEAN = new LintState(DirtyState.clean(), null);
 
 	static Throwable formatStepCausedNoChange() {
 		return FormatterCausedNoChange.INSTANCE;