Unwrap CGLIB proxy when invoking non-proxied methods in ReflectionTestUtils

Prior to this commit, when ReflectionTestUtils was used to invoke a
method on a CGLIB proxy, the invocation was always performed directly
on the proxy. Consequently, if the method was not proxied/intercepted
by the CGLIB proxy -- for example, if the method was final or
effectively private -- the invoked method could not operate on the
state of the target object or interact with other private methods in
the target object.

With this commit, if the supplied target object is a CGLIB proxy which
does not intercept the method, the proxy will be unwrapped allowing the
method to be invoked directly on the ultimate target of the proxy.

Closes gh-33429

Author: sbrannen

spring-test/src/main/java/org/springframework/test/util/ReflectionTestUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -22,6 +22,7 @@
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.aop.support.AopUtils;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -289,22 +290,14 @@ public static Object getField(@Nullable Object targetObject, @Nullable Class<?>
 	/**
 	 * Invoke the setter method with the given {@code name} on the supplied
 	 * target object with the supplied {@code value}.
-	 * <p>This method traverses the class hierarchy in search of the desired
-	 * method. In addition, an attempt will be made to make non-{@code public}
-	 * methods <em>accessible</em>, thus allowing one to invoke {@code protected},
-	 * {@code private}, and <em>package-private</em> setter methods.
-	 * <p>In addition, this method supports JavaBean-style <em>property</em>
-	 * names. For example, if you wish to set the {@code name} property on the
-	 * target object, you may pass either &quot;name&quot; or
-	 * &quot;setName&quot; as the method name.
+	 * <p>This method delegates to
+	 * {@link #invokeSetterMethod(Object, String, Object, Class)}, supplying
+	 * {@code null} for the parameter type.
 	 * @param target the target object on which to invoke the specified setter
 	 * method
 	 * @param name the name of the setter method to invoke or the corresponding
 	 * property name
 	 * @param value the value to provide to the setter method
-	 * @see ReflectionUtils#findMethod(Class, String, Class[])
-	 * @see ReflectionUtils#makeAccessible(Method)
-	 * @see ReflectionUtils#invokeMethod(Method, Object, Object[])
 	 */
 	public static void invokeSetterMethod(Object target, String name, Object value) {
 		invokeSetterMethod(target, name, value, null);
@@ -317,19 +310,24 @@ public static void invokeSetterMethod(Object target, String name, Object value)
 	 * method. In addition, an attempt will be made to make non-{@code public}
 	 * methods <em>accessible</em>, thus allowing one to invoke {@code protected},
 	 * {@code private}, and <em>package-private</em> setter methods.
-	 * <p>In addition, this method supports JavaBean-style <em>property</em>
-	 * names. For example, if you wish to set the {@code name} property on the
-	 * target object, you may pass either &quot;name&quot; or
-	 * &quot;setName&quot; as the method name.
+	 * <p>This method also supports JavaBean-style <em>property</em> names. For
+	 * example, if you wish to set the {@code name} property on the target object,
+	 * you may pass either {@code "name"} or {@code "setName"} as the method name.
+	 * <p>As of Spring Framework 6.2, if the supplied target object is a CGLIB
+	 * proxy which does not intercept the setter method, the proxy will be
+	 * {@linkplain AopTestUtils#getUltimateTargetObject unwrapped} allowing the
+	 * setter method to be invoked directly on the ultimate target of the proxy.
 	 * @param target the target object on which to invoke the specified setter
 	 * method
 	 * @param name the name of the setter method to invoke or the corresponding
 	 * property name
 	 * @param value the value to provide to the setter method
 	 * @param type the formal parameter type declared by the setter method
+	 * (may be {@code null} to indicate any type)
 	 * @see ReflectionUtils#findMethod(Class, String, Class[])
 	 * @see ReflectionUtils#makeAccessible(Method)
 	 * @see ReflectionUtils#invokeMethod(Method, Object, Object[])
+	 * @see AopTestUtils#getUltimateTargetObject(Object)
 	 */
 	public static void invokeSetterMethod(Object target, String name, @Nullable Object value, @Nullable Class<?> type) {
 		Assert.notNull(target, "Target object must not be null");
@@ -357,6 +355,14 @@ public static void invokeSetterMethod(Object target, String name, @Nullable Obje
 					safeToString(target), value));
 		}
 
+		if (springAopPresent) {
+			// If the target is a CGLIB proxy which does not intercept the method, invoke the
+			// method on the ultimate target.
+			if (isCglibProxyThatDoesNotInterceptMethod(target, method)) {
+				target = AopTestUtils.getUltimateTargetObject(target);
+			}
+		}
+
 		ReflectionUtils.makeAccessible(method);
 		ReflectionUtils.invokeMethod(method, target, value);
 	}
@@ -368,10 +374,13 @@ public static void invokeSetterMethod(Object target, String name, @Nullable Obje
 	 * method. In addition, an attempt will be made to make non-{@code public}
 	 * methods <em>accessible</em>, thus allowing one to invoke {@code protected},
 	 * {@code private}, and <em>package-private</em> getter methods.
-	 * <p>In addition, this method supports JavaBean-style <em>property</em>
-	 * names. For example, if you wish to get the {@code name} property on the
-	 * target object, you may pass either &quot;name&quot; or
-	 * &quot;getName&quot; as the method name.
+	 * <p>This method also supports JavaBean-style <em>property</em> names. For
+	 * example, if you wish to get the {@code name} property on the target object,
+	 * you may pass either {@code "name"} or {@code "getName"} as the method name.
+	 * <p>As of Spring Framework 6.2, if the supplied target object is a CGLIB
+	 * proxy which does not intercept the getter method, the proxy will be
+	 * {@linkplain AopTestUtils#getUltimateTargetObject unwrapped} allowing the
+	 * getter method to be invoked directly on the ultimate target of the proxy.
 	 * @param target the target object on which to invoke the specified getter
 	 * method
 	 * @param name the name of the getter method to invoke or the corresponding
@@ -380,6 +389,7 @@ public static void invokeSetterMethod(Object target, String name, @Nullable Obje
 	 * @see ReflectionUtils#findMethod(Class, String, Class[])
 	 * @see ReflectionUtils#makeAccessible(Method)
 	 * @see ReflectionUtils#invokeMethod(Method, Object, Object[])
+	 * @see AopTestUtils#getUltimateTargetObject(Object)
 	 */
 	@Nullable
 	public static Object invokeGetterMethod(Object target, String name) {
@@ -400,6 +410,14 @@ public static Object invokeGetterMethod(Object target, String name) {
 					"Could not find getter method '%s' on %s", getterMethodName, safeToString(target)));
 		}
 
+		if (springAopPresent) {
+			// If the target is a CGLIB proxy which does not intercept the method, invoke the
+			// method on the ultimate target.
+			if (isCglibProxyThatDoesNotInterceptMethod(target, method)) {
+				target = AopTestUtils.getUltimateTargetObject(target);
+			}
+		}
+
 		if (logger.isDebugEnabled()) {
 			logger.debug(String.format("Invoking getter method '%s' on %s", getterMethodName, safeToString(target)));
 		}
@@ -418,10 +436,6 @@ public static Object invokeGetterMethod(Object target, String name) {
 	 * @return the invocation result, if any
 	 * @see #invokeMethod(Class, String, Object...)
 	 * @see #invokeMethod(Object, Class, String, Object...)
-	 * @see MethodInvoker
-	 * @see ReflectionUtils#makeAccessible(Method)
-	 * @see ReflectionUtils#invokeMethod(Method, Object, Object[])
-	 * @see ReflectionUtils#handleReflectionException(Exception)
 	 */
 	@Nullable
 	public static <T> T invokeMethod(Object target, String name, Object... args) {
@@ -441,10 +455,6 @@ public static <T> T invokeMethod(Object target, String name, Object... args) {
 	 * @since 5.2
 	 * @see #invokeMethod(Object, String, Object...)
 	 * @see #invokeMethod(Object, Class, String, Object...)
-	 * @see MethodInvoker
-	 * @see ReflectionUtils#makeAccessible(Method)
-	 * @see ReflectionUtils#invokeMethod(Method, Object, Object[])
-	 * @see ReflectionUtils#handleReflectionException(Exception)
 	 */
 	@Nullable
 	public static <T> T invokeMethod(Class<?> targetClass, String name, Object... args) {
@@ -459,6 +469,10 @@ public static <T> T invokeMethod(Class<?> targetClass, String name, Object... ar
 	 * method. In addition, an attempt will be made to make non-{@code public}
 	 * methods <em>accessible</em>, thus allowing one to invoke {@code protected},
 	 * {@code private}, and <em>package-private</em> methods.
+	 * <p>As of Spring Framework 6.2, if the supplied target object is a CGLIB
+	 * proxy which does not intercept the method, the proxy will be
+	 * {@linkplain AopTestUtils#getUltimateTargetObject unwrapped} allowing the
+	 * method to be invoked directly on the ultimate target of the proxy.
 	 * @param targetObject the target object on which to invoke the method; may
 	 * be {@code null} if the method is static
 	 * @param targetClass the target class on which to invoke the method; may
@@ -471,8 +485,8 @@ public static <T> T invokeMethod(Class<?> targetClass, String name, Object... ar
 	 * @see #invokeMethod(Class, String, Object...)
 	 * @see MethodInvoker
 	 * @see ReflectionUtils#makeAccessible(Method)
-	 * @see ReflectionUtils#invokeMethod(Method, Object, Object[])
 	 * @see ReflectionUtils#handleReflectionException(Exception)
+	 * @see AopTestUtils#getUltimateTargetObject(Object)
 	 */
 	@SuppressWarnings("unchecked")
 	@Nullable
@@ -493,6 +507,15 @@ public static <T> T invokeMethod(@Nullable Object targetObject, @Nullable Class<
 			methodInvoker.setArguments(args);
 			methodInvoker.prepare();
 
+			if (targetObject != null && springAopPresent) {
+				// If the target is a CGLIB proxy which does not intercept the method, invoke the
+				// method on the ultimate target.
+				if (isCglibProxyThatDoesNotInterceptMethod(targetObject, methodInvoker.getPreparedMethod())) {
+					targetObject = AopTestUtils.getUltimateTargetObject(targetObject);
+					methodInvoker.setTargetObject(targetObject);
+				}
+			}
+
 			if (logger.isDebugEnabled()) {
 				logger.debug(String.format("Invoking method '%s' on %s or %s with arguments %s", name,
 						safeToString(targetObject), safeToString(targetClass), ObjectUtils.nullSafeToString(args)));
@@ -520,4 +543,13 @@ private static String safeToString(@Nullable Class<?> clazz) {
 		return String.format("target class [%s]", (clazz != null ? clazz.getName() : null));
 	}
 
+	/**
+	 * Determine if the supplied target object is a CBLIB proxy that does not intercept the
+	 * supplied method.
+	 * @since 6.2
+	 */
+	private static boolean isCglibProxyThatDoesNotInterceptMethod(Object target, Method method) {
+		return (AopUtils.isCglibProxy(target) && !method.getDeclaringClass().equals(target.getClass()));
+	}
+
 }

spring-test/src/test/java/org/springframework/test/util/ReflectionTestUtilsTests.java

@@ -32,6 +32,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+import static org.assertj.core.api.SoftAssertions.assertSoftly;
 import static org.springframework.test.util.ReflectionTestUtils.getField;
 import static org.springframework.test.util.ReflectionTestUtils.invokeGetterMethod;
 import static org.springframework.test.util.ReflectionTestUtils.invokeMethod;
@@ -48,7 +49,7 @@ class ReflectionTestUtilsTests {
 
 	private static final Float PI = (float) 22 / 7;
 
-	private final Person person = new PersonEntity();
+	private final PersonEntity person = new PersonEntity();
 
 	private final Component component = new Component();
 
@@ -156,7 +157,7 @@ private static void assertSetFieldAndGetFieldBehavior(Person person) {
 		assertThat(person.getAge()).as("age (private field)").isEqualTo(42);
 		assertThat(person.getEyeColor()).as("eye color (package private field)").isEqualTo("blue");
 		assertThat(person.likesPets()).as("'likes pets' flag (package private boolean field)").isTrue();
-		assertThat(person.getFavoriteNumber()).as("'favorite number' (package field)").isEqualTo(PI);
+		assertThat(person.getFavoriteNumber()).as("'favorite number' (private field)").isEqualTo(PI);
 	}
 
 	private static void assertSetFieldAndGetFieldBehaviorForProxy(Person proxy, Person target) {
@@ -168,7 +169,7 @@ private static void assertSetFieldAndGetFieldBehaviorForProxy(Person proxy, Pers
 		assertThat(target.getAge()).as("age (private field)").isEqualTo(42);
 		assertThat(target.getEyeColor()).as("eye color (package private field)").isEqualTo("blue");
 		assertThat(target.likesPets()).as("'likes pets' flag (package private boolean field)").isTrue();
-		assertThat(target.getFavoriteNumber()).as("'favorite number' (package field)").isEqualTo(PI);
+		assertThat(target.getFavoriteNumber()).as("'favorite number' (private field)").isEqualTo(PI);
 	}
 
 	@Test
@@ -188,7 +189,7 @@ void setFieldWithNullValuesForNonPrimitives() {
 
 		assertThat(person.getName()).as("name (protected field)").isNull();
 		assertThat(person.getEyeColor()).as("eye color (package private field)").isNull();
-		assertThat(person.getFavoriteNumber()).as("'favorite number' (package field)").isNull();
+		assertThat(person.getFavoriteNumber()).as("'favorite number' (private field)").isNull();
 	}
 
 	@Test
@@ -295,6 +296,22 @@ void invokeSetterMethodAndInvokeGetterMethodWithJavaBeanPropertyNames() {
 		assertThat(invokeGetterMethod(person, "favoriteNumber")).isEqualTo(PI);
 	}
 
+	@Test  // gh-33429
+	void invokingPrivateGetterMethodViaCglibProxyInvokesMethodOnUltimateTarget() {
+		this.person.setPrivateEye("I");
+		ProxyFactory pf = new ProxyFactory(this.person);
+		pf.setProxyTargetClass(true);
+		PersonEntity proxy = (PersonEntity) pf.getProxy();
+		assertThat(AopUtils.isCglibProxy(proxy)).as("Proxy is a CGLIB proxy").isTrue();
+
+		assertSoftly(softly -> {
+			softly.assertThat(getField(this.person, "privateEye")).as("'privateEye' (private field in target)").isEqualTo("I");
+			softly.assertThat(getField(proxy, "privateEye")).as("'privateEye' (private field in proxy)").isEqualTo("I");
+			softly.assertThat(invokeGetterMethod(this.person, "privateEye")).as("'privateEye' (getter on target)").isEqualTo("I");
+			softly.assertThat(invokeGetterMethod(proxy, "privateEye")).as("'privateEye' (getter on proxy)").isEqualTo("I");
+		});
+	}
+
 	@Test
 	void invokeSetterMethodWithNullValuesForNonPrimitives() {
 		invokeSetterMethod(person, "name", null, String.class);
@@ -306,6 +323,41 @@ void invokeSetterMethodWithNullValuesForNonPrimitives() {
 		assertThat(person.getFavoriteNumber()).as("'favorite number' (protected method for a Number)").isNull();
 	}
 
+	@Test  // gh-33429
+	void invokingPrivateSetterMethodViaCglibProxyInvokesMethodOnUltimateTarget() {
+		ProxyFactory pf = new ProxyFactory(this.person);
+		pf.setProxyTargetClass(true);
+		PersonEntity proxy = (PersonEntity) pf.getProxy();
+		assertThat(AopUtils.isCglibProxy(proxy)).as("Proxy is a CGLIB proxy").isTrue();
+
+		// Set reflectively
+		invokeSetterMethod(proxy, "favoriteNumber", PI, Number.class);
+
+		assertSoftly(softly -> {
+			softly.assertThat(getField(proxy, "favoriteNumber")).as("'favorite number' (private field)").isEqualTo(PI);
+			softly.assertThat(proxy.getFavoriteNumber()).as("'favorite number' (getter on proxy)").isEqualTo(PI);
+			softly.assertThat(this.person.getFavoriteNumber()).as("'favorite number' (getter on target)").isEqualTo(PI);
+		});
+	}
+
+	@Test  // gh-33429
+	void invokingFinalSetterMethodViaCglibProxyInvokesMethodOnUltimateTarget() {
+		ProxyFactory pf = new ProxyFactory(this.person);
+		pf.setProxyTargetClass(true);
+		PersonEntity proxy = (PersonEntity) pf.getProxy();
+		assertThat(AopUtils.isCglibProxy(proxy)).as("Proxy is a CGLIB proxy").isTrue();
+		assertThat(proxy.getPuzzle()).as("puzzle").isNull();
+
+		// Set reflectively
+		invokeSetterMethod(proxy, "puzzle", "enigma", String.class);
+
+		assertSoftly(softly -> {
+			softly.assertThat(getField(proxy, "puzzle")).as("'puzzle' (private field)").isEqualTo("enigma");
+			softly.assertThat(proxy.getPuzzle()).as("'puzzle' (getter on proxy)").isEqualTo("enigma");
+			softly.assertThat(this.person.getPuzzle()).as("'puzzle' (getter on target)").isEqualTo("enigma");
+		});
+	}
+
 	@Test
 	void invokeSetterMethodWithNullValueForPrimitiveLong() {
 		assertThatIllegalArgumentException().isThrownBy(() -> invokeSetterMethod(person, "id", null, long.class));
@@ -362,6 +414,23 @@ void invokeMethodSimulatingLifecycleEvents() {
 		assertThat(component.getText()).as("text").isNull();
 	}
 
+	@Test  // gh-33429
+	void invokingPrivateMethodViaCglibProxyInvokesMethodOnUltimateTarget() {
+		ProxyFactory pf = new ProxyFactory(this.person);
+		pf.setProxyTargetClass(true);
+		PersonEntity proxy = (PersonEntity) pf.getProxy();
+		assertThat(AopUtils.isCglibProxy(proxy)).as("Proxy is a CGLIB proxy").isTrue();
+
+		// Set reflectively
+		invokeMethod(proxy, "setFavoriteNumber", PI);
+
+		assertSoftly(softly -> {
+			softly.assertThat(getField(proxy, "favoriteNumber")).as("'favorite number' (private field)").isEqualTo(PI);
+			softly.assertThat(proxy.getFavoriteNumber()).as("'favorite number' (getter on proxy)").isEqualTo(PI);
+			softly.assertThat(this.person.getFavoriteNumber()).as("'favorite number' (getter on target)").isEqualTo(PI);
+		});
+	}
+
 	@Test
 	void invokeInitMethodBeforeAutowiring() {
 		assertThatIllegalStateException()