Make format checking cacheable

Closes gh-164

Author: wilkinsona

spring-javaformat-gradle/spring-javaformat-gradle-plugin/src/main/java/io/spring/javaformat/gradle/CheckTask.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017-2019 the original author or authors.
+ * Copyright 2017-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,10 +18,18 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.StandardOpenOption;
+import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
 
 import org.gradle.api.GradleException;
+import org.gradle.api.file.FileTree;
+import org.gradle.api.tasks.CacheableTask;
+import org.gradle.api.tasks.OutputFile;
+import org.gradle.api.tasks.PathSensitive;
+import org.gradle.api.tasks.PathSensitivity;
 import org.gradle.api.tasks.TaskAction;
 
 import io.spring.javaformat.formatter.FileEdit;
@@ -31,6 +39,7 @@
  *
  * @author Phillip Webb
  */
+@CacheableTask
 public class CheckTask extends FormatterTask {
 
 	/**
@@ -43,20 +52,39 @@ public class CheckTask extends FormatterTask {
 	 */
 	public static final String DESCRIPTION = "Run Spring Java formatting checks";
 
-	public CheckTask() {
-		getOutputs().upToDateWhen((task) -> true);
-	}
+	private File reportLocation;
 
 	@TaskAction
 	public void checkFormatting() throws IOException, InterruptedException {
 		List<File> problems = formatFiles().filter(FileEdit::hasEdits).map(FileEdit::getFile)
 				.collect(Collectors.toList());
+		this.reportLocation.getParentFile().mkdirs();
 		if (!problems.isEmpty()) {
 			StringBuilder message = new StringBuilder("Formatting violations found in the following files:\n");
-			problems.stream().forEach((f) -> message.append(" * " + f + "\n"));
+			problems.stream().forEach((f) -> message.append(" * " + getProject().relativePath(f) + "\n"));
 			message.append("\nRun `format` to fix.");
+			Files.write(this.reportLocation.toPath(), Collections.singletonList(message.toString()),
+					StandardOpenOption.CREATE);
 			throw new GradleException(message.toString());
 		}
+		else {
+			this.reportLocation.createNewFile();
+		}
+	}
+
+	@Override
+	@PathSensitive(PathSensitivity.RELATIVE)
+	public FileTree getSource() {
+		return super.getSource();
+	}
+
+	@OutputFile
+	public File getReportLocation() {
+		return this.reportLocation;
+	}
+
+	public void setReportLocation(File reportLocation) {
+		this.reportLocation = reportLocation;
 	}
 
 }

spring-javaformat-gradle/spring-javaformat-gradle-plugin/src/main/java/io/spring/javaformat/gradle/SpringJavaFormatPlugin.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017-2019 the original author or authors.
+ * Copyright 2017-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,8 @@
 
 package io.spring.javaformat.gradle;
 
+import java.io.File;
+
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
 import org.gradle.api.Task;
@@ -52,6 +54,8 @@ private void addSourceTasks() {
 
 	private void addSourceTasks(SourceSet sourceSet, Task checkAll, Task formatAll) {
 		CheckTask checkTask = addSourceTask(sourceSet, CheckTask.class, CheckTask.NAME, CheckTask.DESCRIPTION);
+		checkTask.setReportLocation(
+				new File(this.project.getBuildDir(), "reports/format/" + sourceSet.getName() + "/check-format.txt"));
 		checkAll.dependsOn(checkTask);
 		FormatTask formatSourceSet = addSourceTask(sourceSet, FormatTask.class, FormatTask.NAME,
 				FormatTask.DESCRIPTION);

spring-javaformat/spring-javaformat-formatter-shader/pom.xml

@@ -9,7 +9,7 @@
 		<version>0.0.19-SNAPSHOT</version>
 	</parent>
 	<artifactId>spring-javaformat-formatter-shader</artifactId>
-	<name>Spring JavaFormat Formatter Shaded</name>
+	<name>Spring JavaFormat Formatter Shader</name>
 	<properties>
 		<main.basedir>${basedir}/../..</main.basedir>
 	</properties>