Allow skipping targets based on text they contain

lib/src/main/java/com/diffplug/spotless/FilterByContentPatternFormatterStep.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2022 DiffPlug
+ * Copyright 2016-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,18 +24,22 @@
 
 final class FilterByContentPatternFormatterStep extends DelegateFormatterStep {
 	final Pattern contentPattern;
+	final boolean formatIfMatches;
 
-	FilterByContentPatternFormatterStep(FormatterStep delegateStep, String contentPattern) {
+	FilterByContentPatternFormatterStep(FormatterStep delegateStep, String contentPattern,
+			boolean formatIfMatches) {
 		super(delegateStep);
 		this.contentPattern = Pattern.compile(Objects.requireNonNull(contentPattern));
+		this.formatIfMatches = formatIfMatches;
 	}
 
 	@Override
 	public @Nullable String format(String raw, File file) throws Exception {
 		Objects.requireNonNull(raw, "raw");
 		Objects.requireNonNull(file, "file");
 		Matcher matcher = contentPattern.matcher(raw);
-		if (matcher.find()) {
+		boolean found = matcher.find();
+		if (formatIfMatches == found) {
 			return delegateStep.format(raw, file);
 		} else {
 			return raw;

lib/src/main/java/com/diffplug/spotless/FormatterStep.java

@@ -54,7 +54,21 @@ public interface FormatterStep extends Serializable {
 	 * @return FormatterStep
 	 */
 	public default FormatterStep filterByContentPattern(String contentPattern) {
-		return new FilterByContentPatternFormatterStep(this, contentPattern);
+		return filterByContentPattern(contentPattern, true);
+	}
+
+	/**
+	 * Returns a new {@code FormatterStep} which, observing the value of {@code formatIfMatches},
+	 * will only apply, or not, its changes to files which pass the given filter.
+	 *
+	 * @param contentPattern
+	 *            java regular expression used to filter in or out files which content contain pattern
+	 * @param formatIfMatches
+	 *            True to format only when {@code contentPattern} is found; false to format only when {@code contentPattern} is not found
+	 * @return FormatterStep
+	 */
+	public default FormatterStep filterByContentPattern(String contentPattern, boolean formatIfMatches) {
+		return new FilterByContentPatternFormatterStep(this, contentPattern, formatIfMatches);
 	}
 
 	/**

plugin-gradle/CHANGES.md

@@ -4,6 +4,8 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 
 ## [Unreleased]
 
+### Added
+* Add target option `targetExcludeIfContentContains` to exclude files by text they contain.
 ### Fixed
 * Correctly support the syntax
   ```

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

@@ -161,6 +161,10 @@ public void encoding(String charset) {
 	/** The files to be formatted = (target - targetExclude). */
 	protected FileCollection target, targetExclude;
 
+	/** The value from which files will be excluded if their content contain it. */
+	@Nullable
+	protected String targetExcludeIfContentContains = null;
+
 	protected boolean isLicenseHeaderStep(FormatterStep formatterStep) {
 		String formatterStepName = formatterStep.getName();
 
@@ -202,6 +206,11 @@ public void targetExclude(Object... targets) {
 		this.targetExclude = parseTargetsIsExclude(targets, true);
 	}
 
+	/** Excludes all files whose content contains {@code value}. */
+	public void targetExcludeIfContentContains(String value) {
+		this.targetExcludeIfContentContains = value;
+	}
+
 	private FileCollection parseTargetsIsExclude(Object[] targets, boolean isExclude) {
 		requireElementsNonNull(targets);
 		if (targets.length == 0) {
@@ -889,6 +898,9 @@ protected void setupTask(SpotlessTask task) {
 		} else {
 			steps = this.steps;
 		}
+		if (targetExcludeIfContentContains != null) {
+			steps.replaceAll(formatterStep -> formatterStep.filterByContentPattern(targetExcludeIfContentContains, false));
+		}
 		task.setSteps(steps);
 		task.setLineEndingsPolicy(getLineEndings().createPolicy(getProject().getProjectDir(), () -> totalTarget));
 		spotless.getRegisterDependenciesTask().hookSubprojectTask(task);

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

@@ -0,0 +1,141 @@
+/*
+ * 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.
+ * 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.jupiter.api.Test;
+
+class TargetExcludeIfContentContainsTest extends GradleIntegrationHarness {
+	@Test
+	void targetExcludeIfContentContainsWithOneValue() throws IOException {
+		setFile("build.gradle").toLines(
+				"plugins { id 'com.diffplug.spotless' }",
+				"spotless {",
+				"  format 'toLower', {",
+				"    target '**/*.md'",
+				"    targetExcludeIfContentContains '// Generated by Mr. Roboto'",
+				"    custom 'lowercase', { str -> str.toLowerCase() }",
+				"  }",
+				"}");
+		String content = "// Generated by Mr. Roboto, do not edit.\n" +
+				"A B C\n" +
+				"D E F\n" +
+				"G H I";
+		setFile("test_generated.md").toContent(content);
+		setFile("test_manual.md").toLines(
+				"A B C",
+				"D E F",
+				"G H I");
+		gradleRunner().withArguments("spotlessApply").build();
+		// `test_generated` contains the excluding text so didn't change.
+		assertFile("test_generated.md").hasContent(content);
+		// `test_manual` does not so it changed.
+		assertFile("test_manual.md").hasLines(
+				"a b c",
+				"d e f",
+				"g h i");
+	}
+
+	@Test
+	void targetExcludeIfContentContainsWithMultipleSteps() throws IOException {
+		setFile("build.gradle").toLines(
+				"plugins { id 'com.diffplug.spotless' }",
+				"spotless {",
+				"  format 'toLower', {",
+				"    target '**/*.md'",
+				"    targetExcludeIfContentContains '// Generated by Mr. Roboto'",
+				"    custom 'lowercase', { str -> str.toLowerCase() }",
+				"    licenseHeader('" + "// My CopyRights header" + "', '--')",
+				"  }",
+				"}");
+		String generatedContent = "// Generated by Mr. Roboto, do not edit.\n" +
+				"--\n" +
+				"public final   class MyMessage {}\n";
+		setFile("test_generated.md").toContent(generatedContent);
+		String manualContent = "// Typo in License\n" +
+				"--\n" +
+				"public final class MyMessage {\n" +
+				"}";
+		setFile("test_manual.md").toContent(manualContent);
+		gradleRunner().withArguments("spotlessApply").build();
+
+		// `test_generated` contains the excluding text so didn't change, including the header.
+		assertFile("test_generated.md").hasContent(generatedContent);
+		// `test_manual` does not, it changed.
+		assertFile("test_manual.md").hasContent(
+				"// My CopyRights header\n" +
+						"--\n" +
+						"public final class mymessage {\n" +
+						"}");
+	}
+
+	@Test
+	void targetExcludeIfContentContainsWithMultipleValues() throws IOException {
+		setFile("build.gradle").toLines(
+				"plugins { id 'com.diffplug.spotless' }",
+				"spotless {",
+				"  format 'toLower', {",
+				"    target '**/*.md'",
+				"    targetExcludeIfContentContains '// Generated by Mr. Roboto|// Generated by Mrs. Call'",
+				"    custom 'lowercase', { str -> str.toLowerCase() }",
+				"  }",
+				"}");
+		String robotoContent = "A B C\n" +
+				"// Generated by Mr. Roboto, do not edit.\n" +
+				"D E F\n" +
+				"G H I";
+		setFile("test_generated_roboto.md").toContent(robotoContent);
+		String callContent = "A B C\n" +
+				"D E F\n" +
+				"// Generated by Mrs. Call, do not edit.\n" +
+				"G H I";
+		setFile("test_generated_call.md").toContent(callContent);
+		String collaborationContent = "A B C\n" +
+				"// Generated by Mr. Roboto, do not edit.\n" +
+				"D E F\n" +
+				"// Generated by Mrs. Call, do not edit.\n" +
+				"G H I";
+		setFile("test_generated_collaboration.md").toContent(collaborationContent);
+		String intruderContent = "A B C\n" +
+				"// Generated by K2000, do not edit.\n" +
+				"D E F\n" +
+				"G H I";
+		setFile("test_generated_intruder.md").toContent(intruderContent);
+		setFile("test_manual.md").toLines(
+				"A B C",
+				"D E F",
+				"G H I");
+		gradleRunner().withArguments("spotlessApply").build();
+		// Part of the excluding values so has not changed.
+		assertFile("test_generated_roboto.md").hasContent(robotoContent);
+		// Part of the excluding values so has not changed.
+		assertFile("test_generated_call.md").hasContent(callContent);
+		// Part of the excluding values so has not changed.
+		assertFile("test_generated_collaboration.md").hasContent(collaborationContent);
+		// Not part of the excluding values so has changed.
+		assertFile("test_generated_intruder.md").hasContent(
+				"a b c\n" +
+						"// generated by k2000, do not edit.\n" +
+						"d e f\n" +
+						"g h i");
+		// `test_manual` does not, it changed.
+		assertFile("test_manual.md").hasLines(
+				"a b c",
+				"d e f",
+				"g h i");
+	}
+}