Add option to use ktlint experimental ruleset

CHANGES.md

@@ -10,6 +10,8 @@ This document is intended for Spotless developers.
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+### Added
+* Added support for enabling ktlint experimental ruleset. ([#1145](https://github.com/diffplug/spotless/pull/1168))
 
 ## [2.24.2] - 2022-04-06
 

build.gradle

@@ -19,7 +19,3 @@ spotless {
 		endWithNewline()
 	}
 }
-
-static Class<?> spotBugsTaskType() {
-	return com.github.spotbugs.snom.SpotBugsTask
-}

lib/build.gradle

@@ -47,6 +47,7 @@ dependencies {
 	String VER_KTLINT='0.43.2'
 	ktlintCompileOnly "com.pinterest:ktlint:$VER_KTLINT"
 	ktlintCompileOnly "com.pinterest.ktlint:ktlint-core:$VER_KTLINT"
+	ktlintCompileOnly "com.pinterest.ktlint:ktlint-ruleset-experimental:$VER_KTLINT"
 	ktlintCompileOnly "com.pinterest.ktlint:ktlint-ruleset-standard:$VER_KTLINT"
 
 	// used for markdown formatting

lib/src/ktlint/java/com/diffplug/spotless/glue/ktlint/KtlintFormatterFunc.java

@@ -16,14 +16,15 @@
 package com.diffplug.spotless.glue.ktlint;
 
 import java.io.File;
-import java.util.Collections;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
 import com.pinterest.ktlint.core.KtLint;
 import com.pinterest.ktlint.core.KtLint.Params;
 import com.pinterest.ktlint.core.LintError;
 import com.pinterest.ktlint.core.RuleSet;
+import com.pinterest.ktlint.ruleset.experimental.ExperimentalRuleSetProvider;
 import com.pinterest.ktlint.ruleset.standard.StandardRuleSetProvider;
 
 import com.diffplug.spotless.FormatterFunc;
@@ -38,8 +39,13 @@ public class KtlintFormatterFunc implements FormatterFunc.NeedsFile {
 	private final Function2<? super LintError, ? super Boolean, Unit> formatterCallback;
 	private final boolean isScript;
 
-	public KtlintFormatterFunc(boolean isScript, Map<String, String> userData) {
-		rulesets = Collections.singletonList(new StandardRuleSetProvider().get());
+	public KtlintFormatterFunc(boolean isScript, boolean useExperimental, Map<String, String> userData) {
+		rulesets = new ArrayList<>();
+		rulesets.add(new StandardRuleSetProvider().get());
+
+		if (useExperimental) {
+			rulesets.add(new ExperimentalRuleSetProvider().get());
+		}
 		this.userData = userData;
 		formatterCallback = new FormatterCallback();
 		this.isScript = isScript;

lib/src/main/java/com/diffplug/spotless/kotlin/KtLintStep.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 DiffPlug
+ * Copyright 2016-2022 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,7 @@
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Proxy;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Map;
 import java.util.Objects;
@@ -49,26 +50,26 @@ public static FormatterStep create(Provisioner provisioner) {
 	}
 
 	public static FormatterStep create(String version, Provisioner provisioner) {
-		return create(version, provisioner, Collections.emptyMap());
+		return create(version, provisioner, false, Collections.emptyMap());
 	}
 
-	public static FormatterStep create(String version, Provisioner provisioner, Map<String, String> userData) {
-		return create(version, provisioner, false, userData);
+	public static FormatterStep create(String version, Provisioner provisioner, boolean useExperimental, Map<String, String> userData) {
+		return create(version, provisioner, false, useExperimental, userData);
 	}
 
 	public static FormatterStep createForScript(String version, Provisioner provisioner) {
-		return create(version, provisioner, true, Collections.emptyMap());
+		return create(version, provisioner, true, false, Collections.emptyMap());
 	}
 
-	public static FormatterStep createForScript(String version, Provisioner provisioner, Map<String, String> userData) {
-		return create(version, provisioner, true, userData);
+	public static FormatterStep createForScript(String version, Provisioner provisioner, boolean useExperimental, Map<String, String> userData) {
+		return create(version, provisioner, true, useExperimental, userData);
 	}
 
-	private static FormatterStep create(String version, Provisioner provisioner, boolean isScript, Map<String, String> userData) {
+	private static FormatterStep create(String version, Provisioner provisioner, boolean isScript, boolean useExperimental, Map<String, String> userData) {
 		Objects.requireNonNull(version, "version");
 		Objects.requireNonNull(provisioner, "provisioner");
 		return FormatterStep.createLazy(NAME,
-				() -> new State(version, provisioner, isScript, userData),
+				() -> new State(version, provisioner, isScript, useExperimental, userData),
 				State::createFormat);
 	}
 
@@ -84,10 +85,12 @@ static final class State implements Serializable {
 		private final String pkg;
 		/** The jar that contains the formatter. */
 		final JarState jarState;
+		private final boolean useExperimental;
 		private final TreeMap<String, String> userData;
 		private final boolean useParams;
 
-		State(String version, Provisioner provisioner, boolean isScript, Map<String, String> userData) throws IOException {
+		State(String version, Provisioner provisioner, boolean isScript, boolean useExperimental, Map<String, String> userData) throws IOException {
+			this.useExperimental = useExperimental;
 			this.userData = new TreeMap<>(userData);
 			String coordinate;
 			if (BadSemver.version(version) < BadSemver.version(0, 32)) {
@@ -105,17 +108,26 @@ static final class State implements Serializable {
 		FormatterFunc createFormat() throws Exception {
 			if (useParams) {
 				Class<?> formatterFunc = jarState.getClassLoader().loadClass("com.diffplug.spotless.glue.ktlint.KtlintFormatterFunc");
-				Constructor<?> constructor = formatterFunc.getConstructor(boolean.class, Map.class);
-				return (FormatterFunc.NeedsFile) constructor.newInstance(isScript, userData);
+				Constructor<?> constructor = formatterFunc.getConstructor(boolean.class, boolean.class, Map.class);
+				return (FormatterFunc.NeedsFile) constructor.newInstance(isScript, useExperimental, userData);
 			}
 
 			ClassLoader classLoader = jarState.getClassLoader();
 			// String KtLint::format(String input, Iterable<RuleSet> rules, Function2 errorCallback)
 
+			ArrayList<Object> ruleSets = new ArrayList<>();
+
 			// first, we get the standard rules
 			Class<?> standardRuleSetProviderClass = classLoader.loadClass(pkg + ".ktlint.ruleset.standard.StandardRuleSetProvider");
 			Object standardRuleSet = standardRuleSetProviderClass.getMethod("get").invoke(standardRuleSetProviderClass.newInstance());
-			Iterable<?> ruleSets = Collections.singletonList(standardRuleSet);
+			ruleSets.add(standardRuleSet);
+
+			// second, we get the experimental rules if desired
+			if (useExperimental) {
+				Class<?> experimentalRuleSetProviderClass = classLoader.loadClass(pkg + ".ktlint.ruleset.experimental.ExperimentalRuleSetProvider");
+				Object experimentalRuleSet = experimentalRuleSetProviderClass.getMethod("get").invoke(experimentalRuleSetProviderClass.newInstance());
+				ruleSets.add(experimentalRuleSet);
+			}
 
 			// next, we create an error callback which throws an assertion error when the format is bad
 			Class<?> function2Interface = classLoader.loadClass("kotlin.jvm.functions.Function2");

plugin-gradle/CHANGES.md

@@ -5,9 +5,9 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 ## [Unreleased]
 ### Added
 * Added a runToFixMessage property to customize the run-to-fix message in spotlessCheck task ([#1175](https://github.com/diffplug/spotless/issues/1175)).
+* Added support for enabling ktlint experimental ruleset. ([#1145](https://github.com/diffplug/spotless/pull/1168))
 
 ## [6.4.2] - 2022-04-06
-
 ### Fixed
 * Git user config and system config also included for defaultEndings configuration. ([#540](https://github.com/diffplug/spotless/issues/540))
 

plugin-gradle/README.md

@@ -340,8 +340,10 @@ spotless {
 ```kotlin
 spotless {
   kotlin {
-    // version and userData are both optional
-    ktlint('0.43.2').userData(mapOf('indent_size' to '2', 'continuation_indent_size' to '2'))
+    // version, setUseExperimental and userData are all optional
+    ktlint('0.43.2')
+      .setUseExperimental(true)
+      .userData(mapOf('indent_size' to '2', 'continuation_indent_size' to '2'))
 ```
 
 ### diktat

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

@@ -59,7 +59,7 @@ public LicenseHeaderConfig licenseHeaderFile(Object licenseHeaderFile) {
 	/** Adds the specified version of <a href="https://github.com/pinterest/ktlint">ktlint</a>. */
 	public KotlinFormatExtension ktlint(String version) {
 		Objects.requireNonNull(version);
-		return new KotlinFormatExtension(version, Collections.emptyMap());
+		return new KotlinFormatExtension(version, false, Collections.emptyMap());
 	}
 
 	public KotlinFormatExtension ktlint() {
@@ -69,23 +69,32 @@ public KotlinFormatExtension ktlint() {
 	public class KotlinFormatExtension {
 
 		private final String version;
+		private boolean useExperimental;
 		private Map<String, String> userData;
 
-		KotlinFormatExtension(String version, Map<String, String> config) {
+		KotlinFormatExtension(String version, boolean useExperimental, Map<String, String> config) {
 			this.version = version;
+			this.useExperimental = useExperimental;
 			this.userData = config;
 			addStep(createStep());
 		}
 
-		public void userData(Map<String, String> userData) {
+		public KotlinFormatExtension setUseExperimental(boolean useExperimental) {
+			this.useExperimental = useExperimental;
+			replaceStep(createStep());
+			return this;
+		}
+
+		public KotlinFormatExtension userData(Map<String, String> userData) {
 			// Copy the map to a sorted map because up-to-date checking is based on binary-equals of the serialized
 			// representation.
 			this.userData = userData;
 			replaceStep(createStep());
+			return this;
 		}
 
 		private FormatterStep createStep() {
-			return KtLintStep.create(version, provisioner(), userData);
+			return KtLintStep.create(version, provisioner(), useExperimental, userData);
 		}
 	}
 

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

@@ -45,7 +45,7 @@ public KotlinGradleExtension(SpotlessExtension spotless) {
 	/** Adds the specified version of <a href="https://github.com/pinterest/ktlint">ktlint</a>. */
 	public KotlinFormatExtension ktlint(String version) {
 		Objects.requireNonNull(version, "version");
-		return new KotlinFormatExtension(version, Collections.emptyMap());
+		return new KotlinFormatExtension(version, false, Collections.emptyMap());
 	}
 
 	public KotlinFormatExtension ktlint() {
@@ -55,23 +55,32 @@ public KotlinFormatExtension ktlint() {
 	public class KotlinFormatExtension {
 
 		private final String version;
+		private boolean useExperimental;
 		private Map<String, String> userData;
 
-		KotlinFormatExtension(String version, Map<String, String> config) {
+		KotlinFormatExtension(String version, boolean useExperimental, Map<String, String> config) {
 			this.version = version;
+			this.useExperimental = useExperimental;
 			this.userData = config;
 			addStep(createStep());
 		}
 
-		public void userData(Map<String, String> userData) {
+		public KotlinFormatExtension setUseExperimental(boolean useExperimental) {
+			this.useExperimental = useExperimental;
+			replaceStep(createStep());
+			return this;
+		}
+
+		public KotlinFormatExtension userData(Map<String, String> userData) {
 			// Copy the map to a sorted map because up-to-date checking is based on binary-equals of the serialized
 			// representation.
 			this.userData = ImmutableSortedMap.copyOf(userData);
 			replaceStep(createStep());
+			return this;
 		}
 
 		private FormatterStep createStep() {
-			return KtLintStep.createForScript(version, provisioner(), userData);
+			return KtLintStep.createForScript(version, provisioner(), useExperimental, userData);
 		}
 	}
 

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

@@ -139,6 +139,67 @@ void testWithIndentation() throws IOException {
 		assertThat(result.getOutput()).contains("Unexpected indentation (4) (it should be 6)");
 	}
 
+	@Test
+	void withExperimental() throws IOException {
+		setFile("build.gradle").toLines(
+				"plugins {",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'com.diffplug.spotless'",
+				"}",
+				"repositories { mavenCentral() }",
+				"spotless {",
+				"    kotlin {",
+				"        ktlint().setUseExperimental(true)",
+				"    }",
+				"}");
+		setFile("src/main/kotlin/experimental.kt").toResource("kotlin/ktlint/experimental.dirty");
+		gradleRunner().withArguments("spotlessApply").build();
+		assertFile("src/main/kotlin/experimental.kt").sameAsResource("kotlin/ktlint/experimental.clean");
+	}
+
+	@Test
+	void withExperimental_0_32() throws IOException {
+		setFile("build.gradle").toLines(
+				"plugins {",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'com.diffplug.spotless'",
+				"}",
+				"repositories { mavenCentral() }",
+				"spotless {",
+				"    kotlin {",
+				"        ktlint('0.32.0').setUseExperimental(true)",
+				"    }",
+				"}");
+		setFile("src/main/kotlin/basic.kt").toResource("kotlin/ktlint/basic.dirty");
+		gradleRunner().withArguments("spotlessApply").build();
+		assertFile("src/main/kotlin/basic.kt").sameAsResource("kotlin/ktlint/basic.clean");
+	}
+
+	/**
+	 * Check that the sample used to verify the experimental ruleset is untouched by the default ruleset, to verify
+	 * that enabling the experimental ruleset is actually doing something.
+	 *
+	 * If this test fails, it's likely that the experimental rule being used as a test graduated into the standard
+	 * ruleset, and therefore a new experimental rule should be used to verify functionality.
+	 */
+	@Test
+	void experimentalSampleUnchangedWithDefaultRuleset() throws IOException {
+		setFile("build.gradle").toLines(
+				"plugins {",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'com.diffplug.spotless'",
+				"}",
+				"repositories { mavenCentral() }",
+				"spotless {",
+				"    kotlin {",
+				"        ktlint()",
+				"    }",
+				"}");
+		setFile("src/main/kotlin/experimental.kt").toResource("kotlin/ktlint/experimental.dirty");
+		gradleRunner().withArguments("spotlessApply").build();
+		assertFile("src/main/kotlin/experimental.kt").sameAsResource("kotlin/ktlint/experimental.dirty");
+	}
+
 	@Test
 	void testWithHeader() throws IOException {
 		setFile("build.gradle").toLines(