Fix fingerprint with deps

.editorconfig

@@ -16,3 +16,6 @@ indent_size = 2
 # Doc: https://youtrack.jetbrains.com/issue/IDEA-170643#focus=streamItem-27-3708697.0-0
 ij_java_imports_layout = java.**,|,javax.**,|,org.**,|,com.**,|,com.diffplug.**,|,*
 ij_java_use_single_class_imports = true
+
+[*.xml.mustache]
+indent_style = space

plugin-maven/CHANGES.md

@@ -3,6 +3,8 @@
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+### Fixed
+* Enabling the upToDateChecking with the plugin configured inside pluginManagement, with an additional dependency and running under Maven 3.6.3 leads to a java.io.NotSerializableException. ([#1074](https://github.com/diffplug/spotless/pull/1074)).
 
 ## [2.19.1] - 2022-01-07
 ### Fixed

plugin-maven/src/main/java/com/diffplug/spotless/maven/incremental/PluginFingerprint.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 DiffPlug
+ * Copyright 2021-2022 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,9 +17,12 @@
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
+import java.util.ArrayList;
 import java.util.Base64;
+import java.util.List;
 import java.util.Objects;
 
+import org.apache.maven.model.Dependency;
 import org.apache.maven.model.Plugin;
 import org.apache.maven.project.MavenProject;
 
@@ -77,6 +80,13 @@ public String toString() {
 	}
 
 	private static byte[] digest(Plugin plugin, Iterable<Formatter> formatters) {
+		// dependencies can be an unserializable org.apache.maven.model.merge.ModelMerger$MergingList
+		// replace it with a serializable ArrayList
+		List<Dependency> dependencies = null;
+		if (plugin != null) {
+			dependencies = plugin.getDependencies();
+			plugin.setDependencies(new ArrayList<>(dependencies));
+		}
 		try (ObjectDigestOutputStream out = ObjectDigestOutputStream.create()) {
 			out.writeObject(plugin);
 			for (Formatter formatter : formatters) {
@@ -86,6 +96,11 @@ private static byte[] digest(Plugin plugin, Iterable<Formatter> formatters) {
 			return out.digest();
 		} catch (IOException e) {
 			throw new UncheckedIOException("Unable to serialize plugin " + plugin, e);
+		} finally {
+			// reset the original list
+			if (plugin != null) {
+				plugin.setDependencies(dependencies);
+			}
 		}
 	}
 }

plugin-maven/src/test/java/com/diffplug/spotless/maven/MavenIntegrationHarness.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 DiffPlug
+ * Copyright 2016-2022 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -57,6 +57,7 @@ public class MavenIntegrationHarness extends ResourceHarness {
 	private static final String CONFIGURATION = "configuration";
 	private static final String EXECUTIONS = "executions";
 	private static final String MODULES = "modules";
+	private static final String DEPENDENCIES = "dependencies";
 	private static final String MODULE_NAME = "name";
 	private static final String CHILD_ID = "childId";
 	private static final int REMOTE_DEBUG_PORT = 5005;
@@ -144,11 +145,11 @@ protected void writePomWithMarkdownSteps(String... steps) throws IOException {
 	}
 
 	protected void writePom(String... configuration) throws IOException {
-		writePom(null, configuration);
+		writePom(null, configuration, null);
 	}
 
-	protected void writePom(String[] executions, String[] configuration) throws IOException {
-		String pomXmlContent = createPomXmlContent(executions, configuration);
+	protected void writePom(String[] executions, String[] configuration, String[] dependencies) throws IOException {
+		String pomXmlContent = createPomXmlContent(null, executions, configuration, dependencies);
 		setFile("pom.xml").toContent(pomXmlContent);
 	}
 
@@ -171,13 +172,17 @@ protected MultiModuleProjectCreator multiModuleProject() {
 		return new MultiModuleProjectCreator();
 	}
 
-	protected String createPomXmlContent(String[] executions, String[] configuration) throws IOException {
-		return createPomXmlContent(null, executions, configuration);
+	protected String createPomXmlContent(String pluginVersion, String[] executions, String[] configuration, String[] dependencies) throws IOException {
+		return createPomXmlContent("/pom-test.xml.mustache", pluginVersion, executions, configuration, dependencies);
+	}
+
+	protected String createPomXmlContent(String pomTemplate, String pluginVersion, String[] executions, String[] configuration, String[] dependencies) throws IOException {
+		Map<String, Object> params = buildPomXmlParams(pluginVersion, executions, configuration, null, dependencies);
+		return createPomXmlContent(pomTemplate, params);
 	}
 
 	protected String createPomXmlContent(String pluginVersion, String[] executions, String[] configuration) throws IOException {
-		Map<String, Object> params = buildPomXmlParams(pluginVersion, executions, configuration, null);
-		return createPomXmlContent("/pom-test.xml.mustache", params);
+		return createPomXmlContent(pluginVersion, executions, configuration, null);
 	}
 
 	private String createPomXmlContent(String pomTemplate, Map<String, Object> params) throws IOException {
@@ -190,7 +195,7 @@ private String createPomXmlContent(String pomTemplate, Map<String, Object> param
 		}
 	}
 
-	private static Map<String, Object> buildPomXmlParams(String pluginVersion, String[] executions, String[] configuration, String[] modules) {
+	private static Map<String, Object> buildPomXmlParams(String pluginVersion, String[] executions, String[] configuration, String[] modules, String[] dependencies) {
 		Map<String, Object> params = new HashMap<>();
 		params.put(SPOTLESS_MAVEN_PLUGIN_VERSION, pluginVersion == null ? getSystemProperty(SPOTLESS_MAVEN_PLUGIN_VERSION) : pluginVersion);
 
@@ -207,6 +212,10 @@ private static Map<String, Object> buildPomXmlParams(String pluginVersion, Strin
 			params.put(MODULES, moduleNames);
 		}
 
+		if (dependencies != null) {
+			params.put(DEPENDENCIES, String.join("\n", dependencies));
+		}
+
 		return params;
 	}
 
@@ -283,7 +292,7 @@ private void createRootPom() throws IOException {
 			modulesList.addAll(subProjects.keySet());
 			String[] modules = modulesList.toArray(new String[0]);
 
-			Map<String, Object> rootPomParams = buildPomXmlParams(null, null, configuration, modules);
+			Map<String, Object> rootPomParams = buildPomXmlParams(null, null, configuration, modules, null);
 			setFile("pom.xml").toContent(createPomXmlContent("/multi-module/pom-parent.xml.mustache", rootPomParams));
 		}
 

plugin-maven/src/test/java/com/diffplug/spotless/maven/SpotlessCheckMojoTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 DiffPlug
+ * Copyright 2016-2022 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -59,7 +59,8 @@ void testSpotlessCheckBindingToVerifyPhase() throws Exception {
 						"  <licenseHeader>",
 						"    <file>${basedir}/license.txt</file>",
 						"  </licenseHeader>",
-						"</java>"});
+						"</java>"},
+				null);
 
 		testSpotlessCheck(UNFORMATTED_FILE, "verify", true);
 	}

plugin-maven/src/test/java/com/diffplug/spotless/maven/incremental/PluginFingerprintTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 DiffPlug
+ * Copyright 2021-2022 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -64,6 +64,25 @@ class PluginFingerprintTest extends MavenIntegrationHarness {
 			"</googleJavaFormat>"
 	};
 
+	private static final String[] DEPENDENCIES_1 = {
+			"<dependencies>",
+			"  <dependency>",
+			"    <groupId>unknown</groupId>",
+			"    <artifactId>unknown</artifactId>",
+			"    <version>1.0</version>",
+			"  </dependency>",
+			"</dependencies>"
+	};
+	private static final String[] DEPENDENCIES_2 = {
+			"<dependencies>",
+			"  <dependency>",
+			"    <groupId>unknown</groupId>",
+			"    <artifactId>unknown</artifactId>",
+			"    <version>2.0</version>",
+			"  </dependency>",
+			"</dependencies>"
+	};
+
 	private static final List<Formatter> FORMATTERS = singletonList(formatter(formatterStep("default")));
 
 	@Test
@@ -80,6 +99,34 @@ void sameFingerprint() throws Exception {
 		assertThat(fingerprint1).isEqualTo(fingerprint2);
 	}
 
+	@Test
+	void sameFingerprintWithDependencies() throws Exception {
+		String xml1 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1, DEPENDENCIES_1);
+		String xml2 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1, DEPENDENCIES_1);
+
+		MavenProject project1 = mavenProject(xml1);
+		MavenProject project2 = mavenProject(xml2);
+
+		PluginFingerprint fingerprint1 = PluginFingerprint.from(project1, FORMATTERS);
+		PluginFingerprint fingerprint2 = PluginFingerprint.from(project2, FORMATTERS);
+
+		assertThat(fingerprint1).isEqualTo(fingerprint2);
+	}
+
+	@Test
+	void differentFingerprintForDifferentDependencies() throws Exception {
+		String xml1 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1, DEPENDENCIES_1);
+		String xml2 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1, DEPENDENCIES_2);
+
+		MavenProject project1 = mavenProject(xml1);
+		MavenProject project2 = mavenProject(xml2);
+
+		PluginFingerprint fingerprint1 = PluginFingerprint.from(project1, FORMATTERS);
+		PluginFingerprint fingerprint2 = PluginFingerprint.from(project2, FORMATTERS);
+
+		assertThat(fingerprint1).isNotEqualTo(fingerprint2);
+	}
+
 	@Test
 	void differentFingerprintForDifferentPluginVersion() throws Exception {
 		String xml1 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1);

plugin-maven/src/test/java/com/diffplug/spotless/maven/incremental/UpToDateCheckingTest.java

@@ -56,6 +56,51 @@ void enableUpToDateChecking() throws Exception {
 		assertFormatted(files);
 	}
 
+	@Test
+	void enableUpToDateCheckingWithPluginDependencies() throws Exception {
+		writePomWithPluginManagementAndDependency();
+
+		List<File> files = writeUnformattedFiles(1);
+		String output = runSpotlessApply();
+
+		assertThat(output).contains("Up-to-date checking enabled");
+		assertFormatted(files);
+	}
+
+	@Test
+	void enableUpToDateCheckingWithPluginDependenciesMaven3_6_3() throws Exception {
+		writePomWithPluginManagementAndDependency();
+
+		setFile(".mvn/wrapper/maven-wrapper.properties").toContent("distributionUrl=https://repo1.maven.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.zip\n");
+
+		List<File> files = writeUnformattedFiles(1);
+		String output = runSpotlessApply();
+
+		assertThat(output).contains("Up-to-date checking enabled");
+		assertFormatted(files);
+	}
+
+	private void writePomWithPluginManagementAndDependency() throws IOException {
+		setFile("pom.xml").toContent(createPomXmlContent("/pom-test-management.xml.mustache",
+				null,
+				null,
+				new String[]{
+						"<java>",
+						"  <googleJavaFormat/>",
+						"</java>",
+						"<upToDateChecking>",
+						"  <enabled>true</enabled>",
+						"</upToDateChecking>"},
+				new String[]{
+						"<dependencies>",
+						"  <dependency>",
+						"    <groupId>javax.inject</groupId>",
+						"    <artifactId>javax.inject</artifactId>",
+						"    <version>1</version>",
+						"  </dependency>",
+						"</dependencies>"}));
+	}
+
 	@Test
 	void disableUpToDateChecking() throws Exception {
 		writePomWithUpToDateCheckingEnabled(false);

plugin-maven/src/test/resources/pom-test-management.xml.mustache

@@ -0,0 +1,47 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.diffplug.spotless</groupId>
+    <artifactId>spotless-maven-plugin-tests</artifactId>
+    <version>1.0.0-SNAPSHOT</version>
+
+    <name>Spotless Maven Plugin Tests</name>
+
+    <!-- Require plugin to be tested with Maven 3.1.0+ -->
+    <prerequisites>
+        <maven>3.1.0</maven>
+    </prerequisites>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+    </properties>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>com.diffplug.spotless</groupId>
+                    <artifactId>spotless-maven-plugin</artifactId>
+                    <version>{{spotlessMavenPluginVersion}}</version>
+                    <configuration>
+                        {{{configuration}}}
+                    </configuration>
+                    {{{dependencies}}}
+                </plugin>
+            </plugins>
+        </pluginManagement>
+        <plugins>
+            <plugin>
+                <groupId>com.diffplug.spotless</groupId>
+                <artifactId>spotless-maven-plugin</artifactId>
+                <executions>
+                    {{{executions}}}
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

plugin-maven/src/test/resources/pom-test.xml.mustache

@@ -31,6 +31,7 @@
                 <executions>
                     {{{executions}}}
                 </executions>
+                {{{dependencies}}}
             </plugin>
         </plugins>
     </build>