Make ClangFormatStep serializable.

Author: nedtwigg

lib/src/main/java/com/diffplug/spotless/cpp/ClangFormatStep.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020-2022 DiffPlug
+ * Copyright 2020-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -64,10 +64,10 @@ public ClangFormatStep withPathToExe(String pathToExe) {
 	}
 
 	public FormatterStep create() {
-		return FormatterStep.createLazy(name(), this::createState, State::toFunc);
+		return FormatterStep.createLazy(name(), this::createState, RoundtripState::state, State::toFunc);
 	}
 
-	private State createState() throws IOException, InterruptedException {
+	private RoundtripState createState() throws IOException, InterruptedException {
 		String howToInstall = "" +
 				"You can download clang-format from https://releases.llvm.org and " +
 				"then point Spotless to it with {@code pathToExe('/path/to/clang-format')} " +
@@ -82,7 +82,25 @@ private State createState() throws IOException, InterruptedException {
 				.fixWrongVersion(
 						"You can tell Spotless to use the version you already have with {@code clangFormat('{versionFound}')}" +
 								"or you can download the currently specified version, {version}.\n" + howToInstall);
-		return new State(this, exe);
+		return new RoundtripState(this, exe);
+	}
+
+	static class RoundtripState implements Serializable {
+		private static final long serialVersionUID = 1L;
+
+		final String version;
+		final @Nullable String style;
+		final ForeignExe exe;
+
+		RoundtripState(ClangFormatStep step, ForeignExe exe) {
+			this.version = step.version;
+			this.style = step.style;
+			this.exe = exe;
+		}
+
+		private State state() {
+			return new State(version, style, exe);
+		}
 	}
 
 	@SuppressFBWarnings("SE_TRANSIENT_FIELD_NOT_RESTORED")
@@ -95,9 +113,9 @@ static class State implements Serializable {
 		// used for executing
 		private transient @Nullable List<String> args;
 
-		State(ClangFormatStep step, ForeignExe pathToExe) {
-			this.version = step.version;
-			this.style = step.style;
+		State(String version, @Nullable String style, ForeignExe pathToExe) {
+			this.version = version;
+			this.style = style;
 			this.exe = Objects.requireNonNull(pathToExe);
 		}
 

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

@@ -17,6 +17,7 @@
 
 import java.util.Locale;
 import java.util.Objects;
+import java.util.Set;
 
 import org.assertj.core.api.Assertions;
 
@@ -48,7 +49,7 @@ protected StepHarnessBase(Formatter formatter) {
 				supportsRoundTrip = true;
 			} else if (onlyStepName.equals("fence")) {
 				supportsRoundTrip = true;
-			} else if (onlyStepName.equals("buf")) {
+			} else if (Set.of("buf", "clang").contains(onlyStepName)) {
 				supportsRoundTrip = true;
 			}
 		}