allow "spotlessFiles" project property in gradle plugin to only target specific files

plugin-gradle/CHANGES.md

@@ -3,6 +3,7 @@
 ### Version 3.17.0-SNAPSHOT - TBD ([javadoc](https://diffplug.github.io/spotless/javadoc/snapshot/), [snapshot](https://oss.sonatype.org/content/repositories/snapshots/com/diffplug/spotless/spotless-plugin-gradle/))
 
 * Updated default eclipse-jdt from 4.7.3a to 4.9.0 ([#316](https://github.com/diffplug/spotless/pull/316)). New version addresses enum-tab formatting bug in 4.8 ([#314](https://github.com/diffplug/spotless/issues/314)).
+* Added `-files` switch to allow targeting specific files ([#322](https://github.com/diffplug/spotless/pull/322))
 
 ### Version 3.16.0 - October 30th 2018 ([javadoc](https://diffplug.github.io/spotless/javadoc/spotless-plugin-gradle/3.16.0/), [jcenter](https://bintray.com/diffplug/opensource/spotless-plugin-gradle/3.16.0))
 

plugin-gradle/README.md

@@ -659,6 +659,16 @@ Note that `enforceCheck` is a global property which affects all formats (outside
 
 <a name="examples"></a>
 
+## Can I apply Spotless to specific files?
+
+You can target specific files by setting the `spotlessFiles` project property to a comma-separated list of file patterns:
+
+```
+cmd> gradlew spotlessApply -PspotlessFiles=my/file/pattern.java,more/generic/.*-pattern.java
+```
+
+The patterns are matched using `String#matches(String)` against the absolute file path.
+
 ## Example configurations (from real-world projects)
 
 Spotless is hosted on jcenter and at plugins.gradle.org. [Go here](https://plugins.gradle.org/plugin/com.diffplug.gradle.spotless) if you're not sure how to import the plugin.

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

@@ -23,13 +23,16 @@
 import java.nio.file.Files;
 import java.nio.file.StandardOpenOption;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
 import java.util.Objects;
+import java.util.function.Predicate;
 
 import org.gradle.api.DefaultTask;
 import org.gradle.api.GradleException;
+import org.gradle.api.Project;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.TaskAction;
@@ -47,6 +50,8 @@
 import com.diffplug.spotless.extra.integration.DiffMessageFormatter;
 
 public class SpotlessTask extends DefaultTask {
+	private static final String FILES_PROPERTY = "spotlessFiles";
+
 	// set by SpotlessExtension, but possibly overridden by FormatExtension
 	protected String encoding = "UTF-8";
 
@@ -168,11 +173,23 @@ public void performAction(IncrementalTaskInputs inputs) throws Exception {
 				.steps(steps)
 				.exceptionPolicy(exceptionPolicy)
 				.build()) {
+			// determine if a list of files has been passed in
+			Predicate<File> shouldInclude;
+			Project project = getProject();
+			if (project.hasProperty(FILES_PROPERTY) && project.property(FILES_PROPERTY) instanceof String) {
+				Object rawIncludePatterns = project.property(FILES_PROPERTY);
+				assert rawIncludePatterns != null;
+				final String[] includePatterns = ((String) rawIncludePatterns).split(",");
+				shouldInclude = file -> Arrays.stream(includePatterns)
+						.anyMatch(filePattern -> file.getAbsolutePath().matches(filePattern));
+			} else {
+				shouldInclude = file -> true;
+			}
 			// find the outOfDate files
 			List<File> outOfDate = new ArrayList<>();
 			inputs.outOfDate(inputDetails -> {
 				File file = inputDetails.getFile();
-				if (file.isFile() && !file.equals(getCacheFile())) {
+				if (file.isFile() && !file.equals(getCacheFile()) && shouldInclude.test(file)) {
 					outOfDate.add(file);
 				}
 			});
@@ -183,7 +200,7 @@ public void performAction(IncrementalTaskInputs inputs) throws Exception {
 			if (getCacheFile().exists()) {
 				LastApply lastApply = SerializableMisc.fromFile(LastApply.class, getCacheFile());
 				for (File file : lastApply.changedFiles) {
-					if (!outOfDate.contains(file) && file.exists() && Iterables.contains(target, file)) {
+					if (!outOfDate.contains(file) && file.exists() && Iterables.contains(target, file) && shouldInclude.test(file)) {
 						outOfDate.add(file);
 					}
 				}

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

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2016 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.gradle.spotless;
+
+import java.io.IOException;
+
+import org.junit.Test;
+
+public class SpecificFilesTest extends GradleIntegrationTest {
+	private String testFile(int number, boolean absolute) throws IOException {
+		String rel = "src/main/java/test" + number + ".java";
+		if (absolute) {
+			return rootFolder() + "/" + rel;
+		} else {
+			return rel;
+		}
+	}
+
+	private String testFile(int number) throws IOException {
+		return testFile(number, false);
+	}
+
+	private String fixture(boolean formatted) {
+		return "java/googlejavaformat/JavaCode" + (formatted ? "F" : "Unf") + "ormatted.test";
+	}
+
+	private void integration(String patterns, boolean firstFormatted, boolean secondFormatted, boolean thirdFormatted)
+			throws IOException {
+
+		setFile("build.gradle").toLines(
+				"buildscript { repositories { mavenCentral() } }",
+				"plugins {",
+				"    id 'com.diffplug.gradle.spotless'",
+				"}",
+				"apply plugin: 'java'",
+				"spotless {",
+				"    java {",
+				"        googleJavaFormat('1.2')",
+				"    }",
+				"}");
+
+		setFile(testFile(1)).toResource(fixture(false));
+		setFile(testFile(2)).toResource(fixture(false));
+		setFile(testFile(3)).toResource(fixture(false));
+
+		gradleRunner()
+				.withArguments("spotlessApply", "-PspotlessFiles=" + patterns)
+				.build();
+
+		assertFile(testFile(1)).sameAsResource(fixture(firstFormatted));
+		assertFile(testFile(2)).sameAsResource(fixture(secondFormatted));
+		assertFile(testFile(3)).sameAsResource(fixture(thirdFormatted));
+	}
+
+	@Test
+	public void singleFile() throws IOException {
+		integration(testFile(2, true), false, true, false);
+	}
+
+	@Test
+	public void multiFile() throws IOException {
+		integration(testFile(1, true) + "," + testFile(3, true), true, false, true);
+	}
+
+	@Test
+	public void regexp() throws IOException {
+		integration(".*/src/main/java/test(1|3).java", true, false, true);
+	}
+}