Merge branch '6.1.x'

Closes gh-13581

config/src/main/java/org/springframework/security/config/annotation/method/configuration/MethodSecurityAdvisorRegistrar.java

@@ -36,6 +36,10 @@ class MethodSecurityAdvisorRegistrar implements ImportBeanDefinitionRegistrar {
 	}
 
 	private void registerAsAdvisor(String prefix, BeanDefinitionRegistry registry) {
+		String advisorName = prefix + "Advisor";
+		if (registry.containsBeanDefinition(advisorName)) {
+			return;
+		}
 		String interceptorName = prefix + "MethodInterceptor";
 		if (!registry.containsBeanDefinition(interceptorName)) {
 			return;

config/src/test/java/org/springframework/security/config/annotation/method/configuration/PrePostMethodSecurityConfigurationTests.java

@@ -20,6 +20,7 @@ import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.function.Consumer;
 import java.util.function.Supplier;
 
 import org.aopalliance.intercept.MethodInterceptor;
@@ -64,6 +65,8 @@ import org.springframework.security.test.context.support.WithSecurityContextTest
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.TestExecutionListeners;
 import org.springframework.test.context.junit.jupiter.SpringExtension;
+import org.springframework.web.context.ConfigurableWebApplicationContext;
+import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
@@ -433,6 +436,17 @@ public class PrePostMethodSecurityConfigurationTests {
 		assertThat(this.spring.getContext().containsBean("annotationSecurityAspect$0")).isFalse();
 	}
 
+	// gh-13572
+	@Test
+	public void configureWhenBeanOverridingDisallowedThenWorks() {
+		this.spring.register(MethodSecurityServiceConfig.class, BusinessServiceConfig.class)
+				.postProcessor(disallowBeanOverriding()).autowire();
+	}
+
+	private static Consumer<ConfigurableWebApplicationContext> disallowBeanOverriding() {
+		return (context) -> ((AnnotationConfigWebApplicationContext) context).setAllowBeanDefinitionOverriding(false);
+	}
+
 	@Configuration
 	@EnableCustomMethodSecurity
 	static class CustomMethodSecurityServiceConfig {