Reduce scope of mavenOptional feature to only the Maven Plugin

Previously, the mavenOptional was added to every published module but it
was only used by spring-boot-maven-plugin. This commit reduces its scope
so that it only affects the Maven plugin. It also reworks the
implementation to reuse the existing optional configuration rather than
declaring a new mavenOptional configuration. Lastly, publication of
Gradle Module Metadata (GMM) has been disabled for
spring-boot-maven-plugin. This is seen as preferable to publishing the
metadata – which isn't really needed as it does not contain any useful
additional information – and having to suppress warnings about
incomplete mapping of GMM to pom metadata.

Closes gh-41263

buildSrc/src/main/java/org/springframework/boot/build/MavenPublishingConventions.java

@@ -19,8 +19,6 @@ package org.springframework.boot.build;
 import org.apache.maven.artifact.repository.MavenArtifactRepository;
 import org.gradle.api.Project;
 import org.gradle.api.attributes.Usage;
-import org.gradle.api.component.AdhocComponentWithVariants;
-import org.gradle.api.component.ConfigurationVariantDetails;
 import org.gradle.api.plugins.JavaPlugin;
 import org.gradle.api.plugins.JavaPluginExtension;
 import org.gradle.api.publish.PublishingExtension;
@@ -101,7 +99,6 @@ class MavenPublishingConventions {
 	}
 
 	private void customizeJavaMavenPublication(MavenPublication publication, Project project) {
-		addMavenOptionalFeature(publication, project);
 		if (publication.getName().equals("pluginMaven")) {
 			return;
 		}
@@ -111,29 +108,6 @@ class MavenPublishingConventions {
 				(strategy) -> strategy.usage(Usage.JAVA_RUNTIME, VariantVersionMappingStrategy::fromResolutionResult));
 	}
 
-	/**
-	 * Add a feature that allows maven plugins to declare optional dependencies that
-	 * appear in the POM. This is required to make m2e in Eclipse happy.
-	 * @param publication the project's Maven publication
-	 * @param project the project to add the feature to
-	 */
-	private void addMavenOptionalFeature(MavenPublication publication, Project project) {
-		JavaPluginExtension extension = project.getExtensions().getByType(JavaPluginExtension.class);
-		extension.registerFeature("mavenOptional",
-				(feature) -> feature.usingSourceSet(extension.getSourceSets().getByName("main")));
-		AdhocComponentWithVariants javaComponent = (AdhocComponentWithVariants) project.getComponents()
-			.findByName("java");
-		javaComponent.addVariantsFromConfiguration(
-				project.getConfigurations().findByName("mavenOptionalRuntimeElements"),
-				ConfigurationVariantDetails::mapToOptional);
-		suppressMavenOptionalFeatureWarnings(publication);
-	}
-
-	private void suppressMavenOptionalFeatureWarnings(MavenPublication publication) {
-		publication.suppressPomMetadataWarningsFor("mavenOptionalApiElements");
-		publication.suppressPomMetadataWarningsFor("mavenOptionalRuntimeElements");
-	}
-
 	private void customizeOrganization(MavenPomOrganization organization) {
 		organization.getName().set("VMware, Inc.");
 		organization.getUrl().set("https://spring.io");

buildSrc/src/main/java/org/springframework/boot/build/mavenplugin/MavenPluginPlugin.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -54,6 +54,8 @@ import org.gradle.api.artifacts.component.ModuleComponentIdentifier;
 import org.gradle.api.artifacts.result.ResolvedArtifactResult;
 import org.gradle.api.attributes.DocsType;
 import org.gradle.api.attributes.Usage;
+import org.gradle.api.component.AdhocComponentWithVariants;
+import org.gradle.api.component.SoftwareComponent;
 import org.gradle.api.file.CopySpec;
 import org.gradle.api.file.DirectoryProperty;
 import org.gradle.api.file.FileCollection;
@@ -65,6 +67,7 @@ import org.gradle.api.plugins.JavaPluginExtension;
 import org.gradle.api.publish.PublishingExtension;
 import org.gradle.api.publish.maven.MavenPublication;
 import org.gradle.api.publish.maven.plugins.MavenPublishPlugin;
+import org.gradle.api.publish.tasks.GenerateModuleMetadata;
 import org.gradle.api.tasks.Classpath;
 import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.JavaExec;
@@ -82,11 +85,14 @@ import org.gradle.api.tasks.bundling.Jar;
 import org.gradle.api.tasks.javadoc.Javadoc;
 import org.gradle.external.javadoc.StandardJavadocDocletOptions;
 import org.w3c.dom.Document;
+import org.w3c.dom.Element;
 import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
 import org.xml.sax.SAXException;
 
 import org.springframework.boot.build.DeployedPlugin;
 import org.springframework.boot.build.MavenRepositoryPlugin;
+import org.springframework.boot.build.optional.OptionalDependenciesPlugin;
 import org.springframework.boot.build.test.DockerTestPlugin;
 import org.springframework.boot.build.test.IntegrationTestPlugin;
 import org.springframework.core.CollectionFactory;
@@ -116,6 +122,33 @@ public class MavenPluginPlugin implements Plugin<Project> {
 		addDocumentPluginGoalsTask(project, generatePluginDescriptorTask);
 		addPrepareMavenBinariesTask(project);
 		addExtractVersionPropertiesTask(project);
+		publishOptionalDependenciesInPom(project);
+		project.getTasks().withType(GenerateModuleMetadata.class).configureEach((task) -> task.setEnabled(false));
+	}
+
+	private void publishOptionalDependenciesInPom(Project project) {
+		project.getPlugins().withType(OptionalDependenciesPlugin.class, (optionalDependencies) -> {
+			SoftwareComponent component = project.getComponents().findByName("java");
+			if (component instanceof AdhocComponentWithVariants componentWithVariants) {
+				componentWithVariants.addVariantsFromConfiguration(
+						project.getConfigurations().getByName(OptionalDependenciesPlugin.OPTIONAL_CONFIGURATION_NAME),
+						(variant) -> variant.mapToOptional());
+			}
+		});
+		MavenPublication publication = (MavenPublication) project.getExtensions()
+			.getByType(PublishingExtension.class)
+			.getPublications()
+			.getByName("maven");
+		publication.getPom().withXml((xml) -> {
+			Element root = xml.asElement();
+			NodeList children = root.getChildNodes();
+			for (int i = 0; i < children.getLength(); i++) {
+				Node child = children.item(i);
+				if ("dependencyManagement".equals(child.getNodeName())) {
+					root.removeChild(child);
+				}
+			}
+		});
 	}
 
 	private void configurePomPackaging(Project project) {

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/build.gradle

@@ -58,17 +58,17 @@ dependencies {
 	intTestImplementation("org.assertj:assertj-core")
 	intTestImplementation("org.junit.jupiter:junit-jupiter")
 
-	mavenOptionalImplementation("org.apache.maven.plugins:maven-shade-plugin") {
-		exclude(group: "javax.annotation", module: "javax.annotation-api")
-		exclude(group: "javax.enterprise", module: "cdi-api")
-		exclude(group: "javax.inject", module: "javax.inject")
-	}
-
 	mavenRepository(project(path: ":spring-boot-project:spring-boot", configuration: "mavenRepository"))
 	mavenRepository(project(path: ":spring-boot-project:spring-boot-test", configuration: "mavenRepository"))
 	mavenRepository(project(path: ":spring-boot-project:spring-boot-devtools", configuration: "mavenRepository"))
 	mavenRepository(project(path: ":spring-boot-project:spring-boot-docker-compose", configuration: "mavenRepository"))
 
+	optional("org.apache.maven.plugins:maven-shade-plugin") {
+		exclude(group: "javax.annotation", module: "javax.annotation-api")
+		exclude(group: "javax.enterprise", module: "cdi-api")
+		exclude(group: "javax.inject", module: "javax.inject")
+	}
+
 	testImplementation("org.apache.maven:maven-core") {
 		exclude(group: "javax.annotation", module: "javax.annotation-api")
 		exclude(group: "javax.inject", module: "javax.inject")