Provide access to underlying ConstraintViolation

Closes gh-33025

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

@@ -50,6 +50,7 @@ import org.springframework.core.MethodParameter;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 import org.springframework.util.function.SingletonSupplier;
 import org.springframework.validation.BeanPropertyBindingResult;
 import org.springframework.validation.BindingResult;
@@ -402,7 +403,7 @@ public class MethodValidationAdapter implements MethodValidator {
 		String[] codes = this.messageCodesResolver.resolveMessageCodes(code, objectName, paramName, parameterType);
 		Object[] arguments = this.validatorAdapter.get().getArgumentsForConstraint(objectName, paramName, descriptor);
 
-		return new DefaultMessageSourceResolvable(codes, arguments, violation.getMessage());
+		return new ViolationMessageSourceResolvable(codes, arguments, violation.getMessage(), violation);
 	}
 
 	private BindingResult createBindingResult(MethodParameter parameter, @Nullable Object argument) {
@@ -472,7 +473,11 @@ public class MethodValidationAdapter implements MethodValidator {
 		public ParameterValidationResult build() {
 			return new ParameterValidationResult(
 					this.parameter, this.value, this.resolvableErrors, this.container,
-					this.containerIndex, this.containerKey);
+					this.containerIndex, this.containerKey,
+					(error, sourceType) -> {
+						Assert.isTrue(sourceType.equals(ConstraintViolation.class), "Unexpected source type");
+						return ((ViolationMessageSourceResolvable) error).getViolation();
+					});
 		}
 	}
 
@@ -526,6 +531,24 @@ public class MethodValidationAdapter implements MethodValidator {
 	}
 
 
+	@SuppressWarnings("serial")
+	private static class ViolationMessageSourceResolvable extends DefaultMessageSourceResolvable {
+
+		private final transient ConstraintViolation<Object> violation;
+
+		public ViolationMessageSourceResolvable(
+				String[] codes, Object[] arguments, String defaultMessage, ConstraintViolation<Object> violation) {
+
+			super(codes, arguments, defaultMessage);
+			this.violation = violation;
+		}
+
+		public ConstraintViolation<Object> getViolation() {
+			return this.violation;
+		}
+	}
+
+
 	/**
 	 * Default algorithm to select an object name, as described in {@link #setObjectNameResolver}.
 	 */

spring-context/src/main/java/org/springframework/validation/method/ParameterErrors.java

@@ -47,7 +47,9 @@ public class ParameterErrors extends ParameterValidationResult implements Errors
 			MethodParameter parameter, @Nullable Object argument, Errors errors,
 			@Nullable Object container, @Nullable Integer index, @Nullable Object key) {
 
-		super(parameter, argument, errors.getAllErrors(), container, index, key);
+		super(parameter, argument, errors.getAllErrors(),
+				container, index, key, (error, sourceType) -> ((FieldError) error).unwrap(sourceType));
+
 		this.errors = errors;
 	}
 

spring-context/src/main/java/org/springframework/validation/method/ParameterValidationResult.java

@@ -18,6 +18,8 @@ package org.springframework.validation.method;
 
 import java.util.Collection;
 import java.util.List;
+import java.util.function.BiFunction;
+import java.util.function.Function;
 
 import org.springframework.context.MessageSourceResolvable;
 import org.springframework.core.MethodParameter;
@@ -62,13 +64,16 @@ public class ParameterValidationResult {
 	@Nullable
 	private final Object containerKey;
 
+	private final BiFunction<MessageSourceResolvable, Class<?>, Object> sourceLookup;
+
 
 	/**
 	 * Create a {@code ParameterValidationResult}.
 	 */
 	public ParameterValidationResult(
 			MethodParameter param, @Nullable Object arg, Collection<? extends MessageSourceResolvable> errors,
-			@Nullable Object container, @Nullable Integer index, @Nullable Object key) {
+			@Nullable Object container, @Nullable Integer index, @Nullable Object key,
+			BiFunction<MessageSourceResolvable, Class<?>, Object> sourceLookup) {
 
 		Assert.notNull(param, "MethodParameter is required");
 		Assert.notEmpty(errors, "`resolvableErrors` must not be empty");
@@ -78,18 +83,36 @@ public class ParameterValidationResult {
 		this.container = container;
 		this.containerIndex = index;
 		this.containerKey = key;
+		this.sourceLookup = sourceLookup;
 	}
 
 	/**
 	 * Create a {@code ParameterValidationResult}.
 	 * @deprecated in favor of
-	 * {@link ParameterValidationResult#ParameterValidationResult(MethodParameter, Object, Collection, Object, Integer, Object)}
+	 * {@link ParameterValidationResult#ParameterValidationResult(MethodParameter, Object, Collection, Object, Integer, Object, Function)}
+	 */
+	@Deprecated(since = "6.2", forRemoval = true)
+	public ParameterValidationResult(
+			MethodParameter param, @Nullable Object arg, Collection<? extends MessageSourceResolvable> errors,
+			@Nullable Object container, @Nullable Integer index, @Nullable Object key) {
+
+		this(param, arg, errors, container, index, key, (error, sourceType) -> {
+			throw new IllegalArgumentException("No source object of the given type");
+		});
+	}
+
+	/**
+	 * Create a {@code ParameterValidationResult}.
+	 * @deprecated in favor of
+	 * {@link ParameterValidationResult#ParameterValidationResult(MethodParameter, Object, Collection, Object, Integer, Object, Function)}
 	 */
 	@Deprecated(since = "6.1.3", forRemoval = true)
 	public ParameterValidationResult(
 			MethodParameter param, @Nullable Object arg, Collection<? extends MessageSourceResolvable> errors) {
 
-		this(param, arg, errors, null, null, null);
+		this(param, arg, errors, null, null, null, (error, sourceType) -> {
+			throw new IllegalArgumentException("No source object of the given type");
+		});
 	}
 
 
@@ -164,6 +187,17 @@ public class ParameterValidationResult {
 		return this.containerKey;
 	}
 
+	/**
+	 * Unwrap the source behind the given error. For Jakarta Bean validation the
+	 * source is a {@link jakarta.validation.ConstraintViolation}.
+	 * @param sourceType the expected source type
+	 * @return the source object of the given type
+	 * @since 6.2
+	 */
+	@SuppressWarnings("unchecked")
+	public <T> T unwrap(MessageSourceResolvable error, Class<T> sourceType) {
+		return (T) this.sourceLookup.apply(error, sourceType);
+	}
 
 	@Override
 	public boolean equals(@Nullable Object other) {

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

@@ -22,6 +22,7 @@ import java.util.Locale;
 import java.util.Set;
 import java.util.function.Consumer;
 
+import jakarta.validation.ConstraintViolation;
 import jakarta.validation.Valid;
 import jakarta.validation.constraints.Max;
 import jakarta.validation.constraints.Min;
@@ -99,7 +100,7 @@ class MethodValidationAdapterTests {
 				default message [must not be blank]"""));
 
 			assertValueResult(ex.getValueResults().get(0), 2, 3, List.of("""
-				org.springframework.context.support.DefaultMessageSourceResolvable: \
+				org.springframework.validation.beanvalidation.MethodValidationAdapter$ViolationMessageSourceResolvable: \
 				codes [Max.myService#addStudent.degrees,Max.degrees,Max.int,Max]; \
 				arguments [org.springframework.context.support.DefaultMessageSourceResolvable: \
 				codes [myService#addStudent.degrees,degrees]; arguments []; default message [degrees],2]; \
@@ -136,7 +137,7 @@ class MethodValidationAdapterTests {
 			assertThat(ex.getAllValidationResults()).hasSize(1);
 
 			assertValueResult(ex.getValueResults().get(0), -1, 4, List.of("""
-				org.springframework.context.support.DefaultMessageSourceResolvable: \
+				org.springframework.validation.beanvalidation.MethodValidationAdapter$ViolationMessageSourceResolvable: \
 				codes [Min.myService#getIntValue,Min,Min.int]; \
 				arguments [org.springframework.context.support.DefaultMessageSourceResolvable: \
 				codes [myService#getIntValue]; arguments []; default message [],5]; \
@@ -204,7 +205,7 @@ class MethodValidationAdapterTests {
 		testArgs(target, method, new Object[] {List.of("   ")}, ex -> {
 			assertThat(ex.getAllValidationResults()).hasSize(1);
 			assertValueResult(ex.getValueResults().get(0), 0, "   ", List.of("""
-				org.springframework.context.support.DefaultMessageSourceResolvable: \
+				org.springframework.validation.beanvalidation.MethodValidationAdapter$ViolationMessageSourceResolvable: \
 				codes [NotBlank.myService#addHobbies.hobbies,NotBlank.hobbies,NotBlank.java.util.List,NotBlank]; \
 				arguments [org.springframework.context.support.DefaultMessageSourceResolvable: \
 				codes [myService#addHobbies.hobbies,hobbies]; \
@@ -220,7 +221,7 @@ class MethodValidationAdapterTests {
 		testArgs(target, method, new Object[] {Set.of("test", "   ")}, ex -> {
 			assertThat(ex.getAllValidationResults()).hasSize(1);
 			assertValueResult(ex.getValueResults().get(0), 0, Set.of("test", "   "), List.of("""
-				org.springframework.context.support.DefaultMessageSourceResolvable: \
+				org.springframework.validation.beanvalidation.MethodValidationAdapter$ViolationMessageSourceResolvable: \
 				codes [NotBlank.myService#addUniqueHobbies.hobbies,NotBlank.hobbies,NotBlank.java.util.Set,NotBlank]; \
 				arguments [org.springframework.context.support.DefaultMessageSourceResolvable: \
 				codes [myService#addUniqueHobbies.hobbies,hobbies]; \
@@ -254,9 +255,14 @@ class MethodValidationAdapterTests {
 
 		assertThat(result.getMethodParameter().getParameterIndex()).isEqualTo(parameterIndex);
 		assertThat(result.getArgument()).isEqualTo(argument);
-		assertThat(result.getResolvableErrors())
+
+		List<MessageSourceResolvable> resolvableErrors = result.getResolvableErrors();
+		assertThat(resolvableErrors)
 				.extracting(MessageSourceResolvable::toString)
 				.containsExactlyInAnyOrderElementsOf(errors);
+
+		resolvableErrors.forEach(error ->
+				assertThat(result.unwrap(error, ConstraintViolation.class)).isNotNull());
 	}
 
 	private static Method getMethod(Object target, String methodName) {

spring-web/src/test/java/org/springframework/web/method/support/HandlerMethodValidationExceptionTests.java

@@ -128,7 +128,8 @@ class HandlerMethodValidationExceptionTests {
 							}
 							else {
 								MessageSourceResolvable error = new DefaultMessageSourceResolvable("Size");
-								return new ParameterValidationResult(param, "123", List.of(error), null, null, null);
+								return new ParameterValidationResult(
+										param, "123", List.of(error), null, null, null, (e, t) -> null);
 							}
 						})
 						.toList());

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/MethodValidationTests.java

@@ -220,7 +220,7 @@ class MethodValidationTests {
 
 					assertValueResult(ex.getValueResults().get(0), 2, "123", Collections.singletonList(
 							"""
-						org.springframework.context.support.DefaultMessageSourceResolvable: \
+						org.springframework.validation.beanvalidation.MethodValidationAdapter$ViolationMessageSourceResolvable: \
 						codes [Size.validController#handle.myHeader,Size.myHeader,Size.java.lang.String,Size]; \
 						arguments [org.springframework.context.support.DefaultMessageSourceResolvable: \
 						codes [validController#handle.myHeader,myHeader]; arguments []; default message [myHeader],10,5]; \
@@ -360,9 +360,15 @@ class MethodValidationTests {
 
 		assertThat(result.getMethodParameter().getParameterIndex()).isEqualTo(parameterIndex);
 		assertThat(result.getArgument()).isEqualTo(argument);
-		assertThat(result.getResolvableErrors())
+
+		List<MessageSourceResolvable> resolvableErrors = result.getResolvableErrors();
+		assertThat(resolvableErrors)
 				.extracting(MessageSourceResolvable::toString)
 				.containsExactlyInAnyOrderElementsOf(errors);
+
+		resolvableErrors.forEach(error ->
+				assertThat(result.unwrap(error, ConstraintViolation.class)).isNotNull());
+
 	}
 
 

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/MethodValidationTests.java

@@ -183,7 +183,7 @@ class MethodValidationTests {
 		));
 
 		assertValueResult(ex.getValueResults().get(0), 2, "123", List.of("""
-			org.springframework.context.support.DefaultMessageSourceResolvable: \
+			org.springframework.validation.beanvalidation.MethodValidationAdapter$ViolationMessageSourceResolvable: \
 			codes [Size.validController#handle.myHeader,Size.myHeader,Size.java.lang.String,Size]; \
 			arguments [org.springframework.context.support.DefaultMessageSourceResolvable: \
 			codes [validController#handle.myHeader,myHeader]; arguments []; default message [myHeader],10,5]; \