Exclude property beans from method validation

Exclude `@ConfigurationProperties` beans from method validation so
that `@Validated` can be used on final classes without the method
validation post-processor throwing an exception.

This commit introduces a `FilteredMethodValidationPostProcessor` class
which will use `MethodValidationExcludeFilters` to exclude beans from
method validation processing. Using `@EnableConfigurationProperties`
will automatically register an appropriate filter.

Closes gh-21454

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/validation/ValidationAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -19,12 +19,15 @@ package org.springframework.boot.autoconfigure.validation;
 import javax.validation.Validator;
 import javax.validation.executable.ExecutableValidator;
 
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnResource;
 import org.springframework.boot.validation.MessageInterpolatorFactory;
+import org.springframework.boot.validation.beanvalidation.FilteredMethodValidationPostProcessor;
+import org.springframework.boot.validation.beanvalidation.MethodValidationExcludeFilter;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
@@ -61,8 +64,9 @@ public class ValidationAutoConfiguration {
 	@Bean
 	@ConditionalOnMissingBean
 	public static MethodValidationPostProcessor methodValidationPostProcessor(Environment environment,
-			@Lazy Validator validator) {
-		MethodValidationPostProcessor processor = new MethodValidationPostProcessor();
+			@Lazy Validator validator, ObjectProvider<MethodValidationExcludeFilter> excludeFilters) {
+		FilteredMethodValidationPostProcessor processor = new FilteredMethodValidationPostProcessor(
+				excludeFilters.orderedStream());
 		boolean proxyTargetClass = environment.getProperty("spring.aop.proxy-target-class", Boolean.class, true);
 		processor.setProxyTargetClass(proxyTargetClass);
 		processor.setValidator(validator);

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/validation/ValidationAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -30,6 +30,7 @@ import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.boot.autoconfigure.validation.ValidationAutoConfigurationTests.CustomValidatorConfiguration.TestBeanPostProcessor;
 import org.springframework.boot.test.util.TestPropertyValues;
+import org.springframework.boot.validation.beanvalidation.MethodValidationExcludeFilter;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -43,6 +44,7 @@ import org.springframework.validation.beanvalidation.OptionalValidatorFactoryBea
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatNoException;
 import static org.mockito.Mockito.mock;
 
 /**
@@ -159,6 +161,15 @@ class ValidationAutoConfigurationTests {
 		assertThatExceptionOfType(ConstraintViolationException.class).isThrownBy(() -> service.doSomething("KO"));
 	}
 
+	@Test
+	void classCanBeExcludedFromValidation() {
+		load(ExcludedServiceConfiguration.class);
+		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(1);
+		ExcludedService service = this.context.getBean(ExcludedService.class);
+		service.doSomething("Valid");
+		assertThatNoException().isThrownBy(() -> service.doSomething("KO"));
+	}
+
 	@Test
 	void validationUsesCglibProxy() {
 		load(DefaultAnotherSampleService.class);
@@ -285,6 +296,29 @@ class ValidationAutoConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static final class ExcludedServiceConfiguration {
+
+		@Bean
+		ExcludedService excludedService() {
+			return new ExcludedService();
+		}
+
+		@Bean
+		MethodValidationExcludeFilter exclusionFilter() {
+			return (type) -> type.equals(ExcludedService.class);
+		}
+
+	}
+
+	@Validated
+	static final class ExcludedService {
+
+		void doSomething(@Size(min = 3, max = 10) String name) {
+		}
+
+	}
+
 	interface AnotherSampleService {
 
 		void doSomething(@Min(42) Integer counter);