Add support to @ClassPathExclusions for excluding packages

Closes gh-36120

Author: wilkinsona

spring-boot-project/spring-boot-tools/spring-boot-test-support/src/main/java/org/springframework/boot/testsupport/classpath/ClassPathExclusions.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2023 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.
@@ -25,6 +25,8 @@
 
 import org.junit.jupiter.api.extension.ExtendWith;
 
+import org.springframework.core.annotation.AliasFor;
+
 /**
  * Annotation used to exclude entries from the classpath.
  *
@@ -37,13 +39,34 @@
 @ExtendWith(ModifiedClassPathExtension.class)
 public @interface ClassPathExclusions {
 
+	/**
+	 * Alias for {@code files}.
+	 * <p>
+	 * One or more Ant-style patterns that identify entries to be excluded from the class
+	 * path. Matching is performed against an entry's {@link File#getName() file name}.
+	 * For example, to exclude Hibernate Validator from the classpath,
+	 * {@code "hibernate-validator-*.jar"} can be used.
+	 * @return the exclusion patterns
+	 */
+	@AliasFor("files")
+	String[] value() default {};
+
 	/**
 	 * One or more Ant-style patterns that identify entries to be excluded from the class
 	 * path. Matching is performed against an entry's {@link File#getName() file name}.
 	 * For example, to exclude Hibernate Validator from the classpath,
 	 * {@code "hibernate-validator-*.jar"} can be used.
 	 * @return the exclusion patterns
+	 * @since 3.2.0
+	 */
+	@AliasFor("value")
+	String[] files() default {};
+
+	/**
+	 * One or more packages that should be excluded from the classpath.
+	 * @return the excluded packages
+	 * @since 3.2.0
 	 */
-	String[] value();
+	String[] packages() default {};
 
 }

spring-boot-project/spring-boot-tools/spring-boot-test-support/src/main/java/org/springframework/boot/testsupport/classpath/ModifiedClassPathClassLoader.java

@@ -26,6 +26,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
@@ -56,6 +57,7 @@
 import org.springframework.core.annotation.MergedAnnotation;
 import org.springframework.core.annotation.MergedAnnotations;
 import org.springframework.util.AntPathMatcher;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.ConcurrentReferenceHashMap;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
@@ -74,10 +76,14 @@ final class ModifiedClassPathClassLoader extends URLClassLoader {
 
 	private static final int MAX_RESOLUTION_ATTEMPTS = 5;
 
+	private final Set<String> excludedPackages;
+
 	private final ClassLoader junitLoader;
 
-	ModifiedClassPathClassLoader(URL[] urls, ClassLoader parent, ClassLoader junitLoader) {
+	ModifiedClassPathClassLoader(URL[] urls, Set<String> excludedPackages, ClassLoader parent,
+			ClassLoader junitLoader) {
 		super(urls, parent);
+		this.excludedPackages = excludedPackages;
 		this.junitLoader = junitLoader;
 	}
 
@@ -87,6 +93,10 @@ public Class<?> loadClass(String name) throws ClassNotFoundException {
 				|| name.startsWith("io.netty.internal.tcnative")) {
 			return Class.forName(name, false, this.junitLoader);
 		}
+		String packageName = ClassUtils.getPackageName(name);
+		if (this.excludedPackages.contains(packageName)) {
+			throw new ClassNotFoundException();
+		}
 		return super.loadClass(name);
 	}
 
@@ -130,7 +140,7 @@ private static ModifiedClassPathClassLoader compute(ClassLoader classLoader,
 			.map((source) -> MergedAnnotations.from(source, MergedAnnotations.SearchStrategy.TYPE_HIERARCHY))
 			.toList();
 		return new ModifiedClassPathClassLoader(processUrls(extractUrls(classLoader), annotations),
-				classLoader.getParent(), classLoader);
+				excludedPackages(annotations), classLoader.getParent(), classLoader);
 	}
 
 	private static URL[] extractUrls(ClassLoader classLoader) {
@@ -269,6 +279,17 @@ private static List<Dependency> createDependencies(String[] allCoordinates) {
 		return dependencies;
 	}
 
+	private static Set<String> excludedPackages(List<MergedAnnotations> annotations) {
+		Set<String> excludedPackages = new HashSet<>();
+		for (MergedAnnotations candidate : annotations) {
+			MergedAnnotation<ClassPathExclusions> annotation = candidate.get(ClassPathExclusions.class);
+			if (annotation.isPresent()) {
+				excludedPackages.addAll(Arrays.asList(annotation.getStringArray("packages")));
+			}
+		}
+		return excludedPackages;
+	}
+
 	/**
 	 * Filter for class path entries.
 	 */

spring-boot-project/spring-boot-tools/spring-boot-test-support/src/test/java/org/springframework/boot/testsupport/classpath/ModifiedClassPathExtensionExclusionsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2023 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.
@@ -19,29 +19,43 @@
 import org.hamcrest.Matcher;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.util.ClassUtils;
+
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.hamcrest.Matchers.isA;
 
 /**
  * Tests for {@link ModifiedClassPathExtension} excluding entries from the class path.
  *
  * @author Christoph Dreis
+ * @author Andy Wilkinson
  */
-@ClassPathExclusions("hibernate-validator-*.jar")
+@ClassPathExclusions(files = "hibernate-validator-*.jar", packages = "java.net.http")
 class ModifiedClassPathExtensionExclusionsTests {
 
 	private static final String EXCLUDED_RESOURCE = "META-INF/services/jakarta.validation.spi.ValidationProvider";
 
 	@Test
-	void entriesAreFilteredFromTestClassClassLoader() {
+	void fileExclusionsAreFilteredFromTestClassClassLoader() {
 		assertThat(getClass().getClassLoader().getResource(EXCLUDED_RESOURCE)).isNull();
 	}
 
 	@Test
-	void entriesAreFilteredFromThreadContextClassLoader() {
+	void fileExclusionsAreFilteredFromThreadContextClassLoader() {
 		assertThat(Thread.currentThread().getContextClassLoader().getResource(EXCLUDED_RESOURCE)).isNull();
 	}
 
+	@Test
+	void packageExclusionsAreFilteredFromTestClassClassLoader() {
+		assertThat(ClassUtils.isPresent("java.net.http.HttpClient", getClass().getClassLoader())).isFalse();
+	}
+
+	@Test
+	void packageExclusionsAreFilteredFromThreadContextClassLoader() {
+		assertThat(ClassUtils.isPresent("java.net.http.HttpClient", Thread.currentThread().getContextClassLoader()))
+			.isFalse();
+	}
+
 	@Test
 	void testsThatUseHamcrestWorkCorrectly() {
 		Matcher<IllegalStateException> matcher = isA(IllegalStateException.class);