Make JacksonJsonStep round-trippable

Author: Goooler

lib/src/main/java/com/diffplug/spotless/json/JacksonJsonStep.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021-2023 DiffPlug
+ * Copyright 2021-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,7 +15,6 @@
  */
 package com.diffplug.spotless.json;
 
-import java.io.IOException;
 import java.io.Serializable;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
@@ -25,48 +24,57 @@
 import com.diffplug.spotless.FormatterStep;
 import com.diffplug.spotless.JarState;
 import com.diffplug.spotless.Provisioner;
+import com.diffplug.spotless.RoundedStep;
 
 /**
  * Simple YAML formatter which reformats the file according to Jackson YAMLFactory.
  */
 // https://stackoverflow.com/questions/14515994/convert-json-string-to-pretty-print-json-output-using-jackson
-public class JacksonJsonStep {
-	static final String MAVEN_COORDINATE = "com.fasterxml.jackson.core:jackson-databind:";
-	// https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind
-	static final String DEFAULT_VERSION = "2.14.2";
+public class JacksonJsonStep implements RoundedStep {
+	private static final long serialVersionUID = 1L;
+	private static final String MAVEN_COORDINATE = "com.fasterxml.jackson.core:jackson-databind:";
+	private static final String DEFAULT_VERSION = "2.14.2";
+	public static final String NAME = "jacksonJson";
 
-	private JacksonJsonStep() {}
+	private final JarState.Promised jarState;
+	private final JacksonConfig jacksonConfig;
+
+	private JacksonJsonStep(JarState.Promised jarState, JacksonConfig jacksonConfig) {
+		this.jarState = jarState;
+		this.jacksonConfig = jacksonConfig;
+	}
 
 	public static String defaultVersion() {
 		return DEFAULT_VERSION;
 	}
 
+	public static FormatterStep create(Provisioner provisioner) {
+		return create(new JacksonJsonConfig(), defaultVersion(), provisioner);
+	}
+
 	public static FormatterStep create(JacksonJsonConfig jacksonConfig,
 			String jacksonVersion,
 			Provisioner provisioner) {
 		Objects.requireNonNull(provisioner, "provisioner cannot be null");
-		return FormatterStep.createLazy("json",
-				() -> new State(jacksonConfig, jacksonVersion, provisioner),
+		return FormatterStep.create(NAME,
+				new JacksonJsonStep(JarState.promise(() -> JarState.from(MAVEN_COORDINATE + jacksonVersion, provisioner)), jacksonConfig),
+				JacksonJsonStep::equalityState,
 				State::toFormatter);
 	}
 
-	public static FormatterStep create(Provisioner provisioner) {
-		return create(new JacksonJsonConfig(), defaultVersion(), provisioner);
+	private State equalityState() {
+		return new State(jarState.get(), jacksonConfig);
 	}
 
 	private static final class State implements Serializable {
 		private static final long serialVersionUID = 1L;
 
 		private final JacksonConfig jacksonConfig;
-
 		private final JarState jarState;
 
-		private State(JacksonConfig jacksonConfig,
-				String jacksonVersion,
-				Provisioner provisioner) throws IOException {
+		State(JarState jarState, JacksonConfig jacksonConfig) {
+			this.jarState = jarState;
 			this.jacksonConfig = jacksonConfig;
-
-			this.jarState = JarState.from(JacksonJsonStep.MAVEN_COORDINATE + jacksonVersion, provisioner);
 		}
 
 		FormatterFunc toFormatter() throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException,

testlib/src/main/java/com/diffplug/spotless/StepHarnessBase.java

@@ -51,7 +51,7 @@ protected StepHarnessBase(Formatter formatter) {
 				supportsRoundTrip = true;
 			} else if (Set.of("black", "buf", "clang", "ktlint", "ktfmt", "scalafmt", "palantir-java-format", "google-java-format",
 					"removeUnusedImports", "cleanthat", "No line break between type annotation and type",
-					"gson",
+					"gson", "jacksonJson",
 					"importOrder", "Remove unnecessary semicolons").contains(onlyStepName)) {
 				supportsRoundTrip = true;
 			}