Merge pull request #323 from larsgrefer

* gh-323:
  Polish "Support up-to-date checking of Format task"
  Support up-to-date checking of Format task

Closes gh-323

Author: wilkinsona

spring-javaformat-gradle/spring-javaformat-gradle-plugin/src/main/java/io/spring/javaformat/gradle/tasks/CheckFormat.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017-2021 the original author or authors.
+ * Copyright 2017-2022 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.
@@ -25,11 +25,8 @@
 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;
@@ -72,12 +69,6 @@ public void checkFormatting() throws IOException, InterruptedException {
 		}
 	}
 
-	@Override
-	@PathSensitive(PathSensitivity.RELATIVE)
-	public FileTree getSource() {
-		return super.getSource();
-	}
-
 	@OutputFile
 	public File getReportLocation() {
 		return this.reportLocation;

spring-javaformat-gradle/spring-javaformat-gradle-plugin/src/main/java/io/spring/javaformat/gradle/tasks/Format.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017-2021 the original author or authors.
+ * Copyright 2017-2022 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.
@@ -19,6 +19,8 @@
 import java.io.IOException;
 
 import org.gradle.api.GradleException;
+import org.gradle.api.file.FileTree;
+import org.gradle.api.tasks.OutputFiles;
 import org.gradle.api.tasks.TaskAction;
 
 import io.spring.javaformat.formatter.FileEdit;
@@ -51,4 +53,9 @@ public void format() throws IOException, InterruptedException {
 		}
 	}
 
+	@OutputFiles
+	public FileTree getOutputFiles() {
+		return super.getSource();
+	}
+
 }

spring-javaformat-gradle/spring-javaformat-gradle-plugin/src/main/java/io/spring/javaformat/gradle/tasks/FormatterTask.java

@@ -19,9 +19,13 @@
 import java.nio.charset.Charset;
 import java.util.stream.Stream;
 
+import org.gradle.api.file.FileTree;
 import org.gradle.api.provider.Property;
 import org.gradle.api.tasks.Input;
+import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.Optional;
+import org.gradle.api.tasks.PathSensitive;
+import org.gradle.api.tasks.PathSensitivity;
 import org.gradle.api.tasks.SourceTask;
 
 import io.spring.javaformat.config.IndentationStyle;
@@ -84,6 +88,13 @@ public Property<JavaBaseline> getJavaBaseline() {
 		return this.javaBaseline;
 	}
 
+	@Override
+	@InputFiles
+	@PathSensitive(PathSensitivity.RELATIVE)
+	public FileTree getSource() {
+		return super.getSource();
+	}
+
 	/**
 	 * Format the source files and provide a {@link Stream} of {@link FileEdit} instances.
 	 * @return the file edits

spring-javaformat-gradle/spring-javaformat-gradle-plugin/src/test/java/io/spring/javaformat/gradle/FormatTaskTests.java

@@ -19,8 +19,10 @@
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
+import java.util.Arrays;
 
 import org.gradle.testkit.runner.BuildResult;
+import org.gradle.testkit.runner.GradleRunner;
 import org.gradle.testkit.runner.TaskOutcome;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
@@ -50,6 +52,45 @@ public void checkOk() throws IOException {
 		assertThat(formattedContent).contains("class Simple {").contains("	public static void main");
 	}
 
+	@Test
+	public void checkUpToDate() throws IOException {
+		GradleRunner runner = this.gradleBuild.source("src/test/resources/format").prepareRunner("format");
+		// Format that changes files
+		assertThat(runner.build().task(":formatMain").getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
+		// Format of already formatted files
+		assertThat(runner.build().task(":formatMain").getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
+		// Up-to-date
+		assertThat(runner.build().task(":formatMain").getOutcome()).isEqualTo(TaskOutcome.UP_TO_DATE);
+	}
+
+	@Test
+	public void notUpToDateWhenJavaBaselineChanges() throws IOException {
+		GradleRunner runner = this.gradleBuild.source("src/test/resources/format").prepareRunner("format");
+		// Format that changes files
+		assertThat(runner.build().task(":formatMain").getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
+		// Format of already formatted files
+		assertThat(runner.build().task(":formatMain").getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
+		// Up-to-date
+		assertThat(runner.build().task(":formatMain").getOutcome()).isEqualTo(TaskOutcome.UP_TO_DATE);
+		Files.write(new File(this.gradleBuild.getProjectDir(), ".springjavaformatconfig").toPath(),
+				Arrays.asList("java-baseline=8"));
+		assertThat(runner.build().task(":formatMain").getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
+	}
+
+	@Test
+	public void notUpToDateWhenIndentationStyleChanges() throws IOException {
+		GradleRunner runner = this.gradleBuild.source("src/test/resources/format").prepareRunner("format");
+		// Format that changes files
+		assertThat(runner.build().task(":formatMain").getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
+		// Format of already formatted files
+		assertThat(runner.build().task(":formatMain").getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
+		// Up-to-date
+		assertThat(runner.build().task(":formatMain").getOutcome()).isEqualTo(TaskOutcome.UP_TO_DATE);
+		Files.write(new File(this.gradleBuild.getProjectDir(), ".springjavaformatconfig").toPath(),
+				Arrays.asList("indentation-style=spaces"));
+		assertThat(runner.build().task(":formatMain").getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
+	}
+
 	@Test
 	public void checkSpacesOk() throws IOException {
 		BuildResult result = this.gradleBuild.source("src/test/resources/format-spaces").build("format");