Do not require aspectjweaver to enable CGLib-based proxies

Previously, AopAutoConfiguration would only enable CGLib-based
proxies if aspectjweaver was on the classpath. The intention was for
CGLib-based proxies to always be used by default so this behaviour
was incorrect.

This commit updates AopAutoConfiguration to force the use of
CGLib-based proxies even in the absence of aspectjweaver.

Closes gh-18523

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/aop/AopAutoConfiguration.java

@@ -16,11 +16,13 @@
 
 package org.springframework.boot.autoconfigure.aop;
 
-import org.aspectj.lang.annotation.Aspect;
-import org.aspectj.lang.reflect.Advice;
-import org.aspectj.weaver.AnnotatedElement;
+import org.aspectj.weaver.Advice;
 
+import org.springframework.aop.config.AopConfigUtils;
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.EnableAspectJAutoProxy;
@@ -40,23 +42,44 @@ import org.springframework.context.annotation.EnableAspectJAutoProxy;
  * @see EnableAspectJAutoProxy
  */
 @Configuration(proxyBeanMethods = false)
-@ConditionalOnClass({ EnableAspectJAutoProxy.class, Aspect.class, Advice.class, AnnotatedElement.class })
 @ConditionalOnProperty(prefix = "spring.aop", name = "auto", havingValue = "true", matchIfMissing = true)
 public class AopAutoConfiguration {
 
 	@Configuration(proxyBeanMethods = false)
-	@EnableAspectJAutoProxy(proxyTargetClass = false)
-	@ConditionalOnProperty(prefix = "spring.aop", name = "proxy-target-class", havingValue = "false",
-			matchIfMissing = false)
-	public static class JdkDynamicAutoProxyConfiguration {
+	@ConditionalOnClass(Advice.class)
+	static class AspectJAutoProxyingConfiguration {
+
+		@Configuration(proxyBeanMethods = false)
+		@EnableAspectJAutoProxy(proxyTargetClass = false)
+		@ConditionalOnProperty(prefix = "spring.aop", name = "proxy-target-class", havingValue = "false",
+				matchIfMissing = false)
+		static class JdkDynamicAutoProxyConfiguration {
+
+		}
+
+		@Configuration(proxyBeanMethods = false)
+		@EnableAspectJAutoProxy(proxyTargetClass = true)
+		@ConditionalOnProperty(prefix = "spring.aop", name = "proxy-target-class", havingValue = "true",
+				matchIfMissing = true)
+		static class CglibAutoProxyConfiguration {
+
+		}
 
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	@EnableAspectJAutoProxy(proxyTargetClass = true)
+	@ConditionalOnMissingClass("org.aspectj.weaver.Advice")
 	@ConditionalOnProperty(prefix = "spring.aop", name = "proxy-target-class", havingValue = "true",
 			matchIfMissing = true)
-	public static class CglibAutoProxyConfiguration {
+	static class ClassProxyingConfiguration {
+
+		ClassProxyingConfiguration(BeanFactory beanFactory) {
+			if (beanFactory instanceof BeanDefinitionRegistry) {
+				BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
+				AopConfigUtils.registerAutoProxyCreatorIfNecessary(registry);
+				AopConfigUtils.forceAutoProxyCreatorToUseClassProxying(registry);
+			}
+		}
 
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/aop/NonAspectJAopAutoConfigurationTests.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2012-2019 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.autoconfigure.aop;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.aop.config.AopConfigUtils;
+import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListener;
+import org.springframework.boot.logging.LogLevel;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.boot.testsupport.classpath.ClassPathExclusions;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link AopAutoConfiguration} without AspectJ.
+ *
+ * @author Andy Wilkinson
+ */
+@ClassPathExclusions("aspectjweaver*.jar")
+class NonAspectJAopAutoConfigurationTests {
+
+	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+			.withConfiguration(AutoConfigurations.of(AopAutoConfiguration.class));
+
+	@Test
+	void whenAspectJIsAbsentAndProxyTargetClassIsEnabledProxyCreatorBeanIsDefined() {
+		this.contextRunner.withInitializer(new ConditionEvaluationReportLoggingListener(LogLevel.INFO))
+				.run((context) -> {
+					BeanDefinition autoProxyCreator = context.getBeanFactory()
+							.getBeanDefinition(AopConfigUtils.AUTO_PROXY_CREATOR_BEAN_NAME);
+					assertThat(autoProxyCreator.getPropertyValues().get("proxyTargetClass")).isEqualTo(Boolean.TRUE);
+				});
+	}
+
+	@Test
+	void whenAspectJIsAbsentAndProxyTargetClassIsDisabledNoProxyCreatorBeanIsDefined() {
+		this.contextRunner.withPropertyValues("spring.aop.proxy-target-class:false")
+				.run((context) -> assertThat(context).doesNotHaveBean(AopConfigUtils.AUTO_PROXY_CREATOR_BEAN_NAME));
+	}
+
+}