Lazily obtain Validator from original Supplier

Closes gh-31137

Author: jhoeller

spring-context/src/main/java/org/springframework/validation/beanvalidation/MethodValidationAdapter.java

@@ -133,9 +133,10 @@ public MethodValidationAdapter(Supplier<Validator> validator) {
 	}
 
 	private static Supplier<SpringValidatorAdapter> initValidatorAdapter(Supplier<Validator> validatorSupplier) {
-		Validator validator = validatorSupplier.get();
-		return (validator instanceof SpringValidatorAdapter validatorAdapter ?
-				(() -> validatorAdapter) : SingletonSupplier.of(() -> new SpringValidatorAdapter(validator)));
+		return SingletonSupplier.of(() -> {
+			Validator validator = validatorSupplier.get();
+			return (validator instanceof SpringValidatorAdapter sva ? sva : new SpringValidatorAdapter(validator));
+		});
 	}
 
 

spring-context/src/test/java/org/springframework/validation/beanvalidation/MethodValidationProxyTests.java

@@ -32,6 +32,7 @@
 import org.springframework.aop.framework.ProxyFactory;
 import org.springframework.beans.MutablePropertyValues;
 import org.springframework.beans.factory.FactoryBean;
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -54,7 +55,7 @@
  * and/or {@link MethodValidationPostProcessor}.
  *
  * @author Juergen Hoeller
- * @author Rossen Stoyanchevß
+ * @author Rossen Stoyanchev
  */
 public class MethodValidationProxyTests {
 
@@ -109,19 +110,29 @@ private void doTestProxyValidation(MyValidInterface<String> proxy) {
 
 	@Test
 	public void testLazyValidatorForMethodValidation() {
-		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(
-				LazyMethodValidationConfig.class, CustomValidatorBean.class,
-				MyValidBean.class, MyValidFactoryBean.class);
-		context.getBeansOfType(MyValidInterface.class).values().forEach(bean -> bean.myValidMethod("value", 5));
-		context.close();
+		doTestLazyValidatorForMethodValidation(LazyMethodValidationConfig.class);
 	}
 
 	@Test
 	public void testLazyValidatorForMethodValidationWithProxyTargetClass() {
-		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(
-				LazyMethodValidationConfigWithProxyTargetClass.class, CustomValidatorBean.class,
-				MyValidBean.class, MyValidFactoryBean.class);
+		doTestLazyValidatorForMethodValidation(LazyMethodValidationConfigWithProxyTargetClass.class);
+	}
+
+	@Test
+	public void testLazyValidatorForMethodValidationWithValidatorProvider() {
+		doTestLazyValidatorForMethodValidation(LazyMethodValidationConfigWithValidatorProvider.class);
+	}
+
+	private void doTestLazyValidatorForMethodValidation(Class<?> configClass) {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+		context.register(configClass, CustomValidatorBean.class, MyValidBean.class, MyValidFactoryBean.class);
+		context.getDefaultListableBeanFactory().getBeanDefinition("customValidatorBean").setLazyInit(true);
+		context.refresh();
+
+		assertThat(context.getDefaultListableBeanFactory().containsSingleton("customValidatorBean")).isFalse();
 		context.getBeansOfType(MyValidInterface.class).values().forEach(bean -> bean.myValidMethod("value", 5));
+		assertThat(context.getDefaultListableBeanFactory().containsSingleton("customValidatorBean")).isTrue();
+
 		context.close();
 	}
 
@@ -256,4 +267,16 @@ public static MethodValidationPostProcessor methodValidationPostProcessor(@Lazy
 		}
 	}
 
+
+	@Configuration
+	public static class LazyMethodValidationConfigWithValidatorProvider {
+
+		@Bean
+		public static MethodValidationPostProcessor methodValidationPostProcessor(ObjectProvider<Validator> validator) {
+			MethodValidationPostProcessor postProcessor = new MethodValidationPostProcessor();
+			postProcessor.setValidatorProvider(validator);
+			return postProcessor;
+		}
+	}
+
 }