Configure attributes on productionRuntimeClasspath

Previously, the productionRuntimeClasspath configuration was created
without any attributes. This caused problems with multi-project
dependency resolution as there was insufficient information for Gradle
to determine which variant of a dependency should be used by the
productionRuntimeClasspath configuration.

This commit updates the configuration to have three attributes, each
configured with the same values as those of Gradle's own
runtimeClasspathConfiguration.

Fixes gh-21549

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/JavaPluginAction.java

@@ -28,8 +28,13 @@ import org.gradle.api.Plugin;
 import org.gradle.api.Project;
 import org.gradle.api.Task;
 import org.gradle.api.artifacts.Configuration;
+import org.gradle.api.attributes.AttributeContainer;
+import org.gradle.api.attributes.Bundling;
+import org.gradle.api.attributes.LibraryElements;
+import org.gradle.api.attributes.Usage;
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.internal.artifacts.dsl.LazyPublishArtifact;
+import org.gradle.api.model.ObjectFactory;
 import org.gradle.api.plugins.ApplicationPlugin;
 import org.gradle.api.plugins.BasePlugin;
 import org.gradle.api.plugins.JavaPlugin;
@@ -174,6 +179,12 @@ final class JavaPluginAction implements PluginApplicationAction {
 				.getByName(JavaPlugin.RUNTIME_CLASSPATH_CONFIGURATION_NAME);
 		Configuration productionRuntimeClasspath = project.getConfigurations()
 				.create(SpringBootPlugin.PRODUCTION_RUNTIME_CLASSPATH_NAME);
+		AttributeContainer attributes = productionRuntimeClasspath.getAttributes();
+		ObjectFactory objectFactory = project.getObjects();
+		attributes.attribute(Usage.USAGE_ATTRIBUTE, objectFactory.named(Usage.class, Usage.JAVA_RUNTIME));
+		attributes.attribute(Bundling.BUNDLING_ATTRIBUTE, objectFactory.named(Bundling.class, Bundling.EXTERNAL));
+		attributes.attribute(LibraryElements.LIBRARY_ELEMENTS_ATTRIBUTE,
+				objectFactory.named(LibraryElements.class, LibraryElements.JAR));
 		productionRuntimeClasspath.setVisible(false);
 		productionRuntimeClasspath.setExtendsFrom(runtimeClasspath.getExtendsFrom());
 		runtimeClasspath.extendsFrom(developmentOnly);

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/plugin/JavaPluginActionIntegrationTests.java

@@ -146,6 +146,15 @@ class JavaPluginActionIntegrationTests {
 						.contains("developmentOnly exists = true");
 	}
 
+	@TestTemplate
+	void productionRuntimeClasspathIsConfiguredWithAttributes() {
+		assertThat(this.gradleBuild
+				.build("configurationAttributes", "-PconfigurationName=productionRuntimeClasspath", "-PapplyJavaPlugin")
+				.getOutput()).contains("3 productionRuntimeClasspath attributes:")
+						.contains("org.gradle.usage: java-runtime").contains("org.gradle.libraryelements: jar")
+						.contains("org.gradle.dependency.bundling: external");
+	}
+
 	private void createMinimalMainSource() throws IOException {
 		File examplePackage = new File(this.gradleBuild.getProjectDir(), "src/main/java/com/example");
 		examplePackage.mkdirs();

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/plugin/JavaPluginActionIntegrationTests.gradle

@@ -25,3 +25,13 @@ task('configurationExists') {
 		println "${configurationName} exists = ${configurations.findByName(configurationName) != null}"
 	}
 }
+
+task('configurationAttributes') {
+	doFirst {
+		def attributes = configurations.findByName(configurationName).attributes
+		println "${attributes.keySet().size()} ${configurationName} attributes:"		
+		attributes.keySet().each { attribute ->
+			println "    ${attribute}: ${attributes.getAttribute(attribute)}" 
+		}
+	}
+}