Support cross-parameter validation

Closes gh-33271

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

@@ -18,6 +18,7 @@ package org.springframework.validation.beanvalidation;
 
 import java.lang.reflect.Method;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.Comparator;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
@@ -301,6 +302,7 @@ public class MethodValidationAdapter implements MethodValidator {
 
 		Map<Path.Node, ParamValidationResultBuilder> paramViolations = new LinkedHashMap<>();
 		Map<Path.Node, ParamErrorsBuilder> nestedViolations = new LinkedHashMap<>();
+		List<MessageSourceResolvable> crossParamErrors = null;
 
 		for (ConstraintViolation<Object> violation : violations) {
 			Iterator<Path.Node> nodes = violation.getPropertyPath().iterator();
@@ -315,6 +317,11 @@ public class MethodValidationAdapter implements MethodValidator {
 				else if (node.getKind().equals(ElementKind.RETURN_VALUE)) {
 					parameter = parameterFunction.apply(-1);
 				}
+				else if (node.getKind().equals(ElementKind.CROSS_PARAMETER)) {
+					crossParamErrors = (crossParamErrors != null ? crossParamErrors : new ArrayList<>());
+					crossParamErrors.add(createCrossParamError(target, method, violation));
+					break;
+				}
 				else {
 					continue;
 				}
@@ -382,7 +389,8 @@ public class MethodValidationAdapter implements MethodValidator {
 		nestedViolations.forEach((key, builder) -> resultList.add(builder.build()));
 		resultList.sort(resultComparator);
 
-		return MethodValidationResult.create(target, method, resultList);
+		return MethodValidationResult.create(target, method, resultList,
+				(crossParamErrors != null ? crossParamErrors : Collections.emptyList()));
 	}
 
 	private MethodParameter initMethodParameter(Method method, int index) {
@@ -413,6 +421,19 @@ public class MethodValidationAdapter implements MethodValidator {
 		return result;
 	}
 
+	private MessageSourceResolvable createCrossParamError(
+			Object target, Method method, ConstraintViolation<Object> violation) {
+
+		String objectName = Conventions.getVariableName(target) + "#" + method.getName();
+
+		ConstraintDescriptor<?> descriptor = violation.getConstraintDescriptor();
+		String code = descriptor.getAnnotation().annotationType().getSimpleName();
+		String[] codes = this.messageCodesResolver.resolveMessageCodes(code, objectName);
+		Object[] arguments = this.validatorAdapter.get().getArgumentsForConstraint(objectName, "", descriptor);
+
+		return new ViolationMessageSourceResolvable(codes, arguments, violation.getMessage(), violation);
+	}
+
 
 	/**
 	 * Strategy to resolve the name of an {@code @Valid} method parameter to

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -19,6 +19,7 @@ package org.springframework.validation.method;
 import java.lang.reflect.Method;
 import java.util.List;
 
+import org.springframework.context.MessageSourceResolvable;
 import org.springframework.util.Assert;
 
 /**
@@ -33,19 +34,26 @@ final class DefaultMethodValidationResult implements MethodValidationResult {
 
 	private final Method method;
 
-	private final List<ParameterValidationResult> allValidationResults;
+	private final List<ParameterValidationResult> parameterValidationResults;
+
+	private final List<MessageSourceResolvable> crossParamResults;
 
 	private final boolean forReturnValue;
 
 
-	DefaultMethodValidationResult(Object target, Method method, List<ParameterValidationResult> results) {
-		Assert.notEmpty(results, "'results' is required and must not be empty");
+	DefaultMethodValidationResult(
+			Object target, Method method, List<ParameterValidationResult> results,
+			List<MessageSourceResolvable> crossParamResults) {
+
+		Assert.isTrue(!results.isEmpty() || !crossParamResults.isEmpty(), "Expected validation results");
 		Assert.notNull(target, "'target' is required");
 		Assert.notNull(method, "Method is required");
+
 		this.target = target;
 		this.method = method;
-		this.allValidationResults = results;
-		this.forReturnValue = (results.get(0).getMethodParameter().getParameterIndex() == -1);
+		this.parameterValidationResults = results;
+		this.crossParamResults = crossParamResults;
+		this.forReturnValue = (!results.isEmpty() && results.get(0).getMethodParameter().getParameterIndex() == -1);
 	}
 
 
@@ -65,10 +73,14 @@ final class DefaultMethodValidationResult implements MethodValidationResult {
 	}
 
 	@Override
-	public List<ParameterValidationResult> getAllValidationResults() {
-		return this.allValidationResults;
+	public List<ParameterValidationResult> getParameterValidationResults() {
+		return this.parameterValidationResults;
 	}
 
+	@Override
+	public List<MessageSourceResolvable> getCrossParameterValidationResults() {
+		return this.crossParamResults;
+	}
 
 	@Override
 	public String toString() {

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -20,6 +20,8 @@ import java.lang.reflect.Method;
 import java.util.Collections;
 import java.util.List;
 
+import org.springframework.context.MessageSourceResolvable;
+
 /**
  * {@link MethodValidationResult} with an empty list of results.
  *
@@ -44,7 +46,12 @@ final class EmptyMethodValidationResult implements MethodValidationResult {
 	}
 
 	@Override
-	public List<ParameterValidationResult> getAllValidationResults() {
+	public List<ParameterValidationResult> getParameterValidationResults() {
+		return Collections.emptyList();
+	}
+
+	@Override
+	public List<MessageSourceResolvable> getCrossParameterValidationResults() {
 		return Collections.emptyList();
 	}
 

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -19,6 +19,7 @@ package org.springframework.validation.method;
 import java.lang.reflect.Method;
 import java.util.List;
 
+import org.springframework.context.MessageSourceResolvable;
 import org.springframework.util.Assert;
 
 /**
@@ -57,8 +58,13 @@ public class MethodValidationException extends RuntimeException implements Metho
 	}
 
 	@Override
-	public List<ParameterValidationResult> getAllValidationResults() {
-		return this.validationResult.getAllValidationResults();
+	public List<ParameterValidationResult> getParameterValidationResults() {
+		return this.validationResult.getParameterValidationResults();
+	}
+
+	@Override
+	public List<MessageSourceResolvable> getCrossParameterValidationResults() {
+		return this.validationResult.getCrossParameterValidationResults();
 	}
 
 }

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

@@ -17,6 +17,7 @@
 package org.springframework.validation.method;
 
 import java.lang.reflect.Method;
+import java.util.Collections;
 import java.util.List;
 
 import org.springframework.context.MessageSourceResolvable;
@@ -55,54 +56,75 @@ public interface MethodValidationResult {
 	 * Whether the result contains any validation errors.
 	 */
 	default boolean hasErrors() {
-		return !getAllValidationResults().isEmpty();
+		return !getParameterValidationResults().isEmpty();
 	}
 
 	/**
 	 * Return a single list with all errors from all validation results.
-	 * @see #getAllValidationResults()
+	 * @see #getParameterValidationResults()
 	 * @see ParameterValidationResult#getResolvableErrors()
 	 */
 	default List<? extends MessageSourceResolvable> getAllErrors() {
-		return getAllValidationResults().stream()
+		return getParameterValidationResults().stream()
 				.flatMap(result -> result.getResolvableErrors().stream())
 				.toList();
 	}
 
+	/**
+	 * Return all validation results per method parameter, including both
+	 * {@link #getValueResults()} and {@link #getBeanResults()}.
+	 * <p>Use {@link #getCrossParameterValidationResults()} for access to errors
+	 * from cross-parameter validation.
+	 * @since 6.2
+	 * @see #getValueResults()
+	 * @see #getBeanResults()
+	 */
+	List<ParameterValidationResult> getParameterValidationResults();
+
 	/**
 	 * Return all validation results. This includes both method parameters with
 	 * errors directly on them, and Object method parameters with nested errors
 	 * on their fields and properties.
 	 * @see #getValueResults()
 	 * @see #getBeanResults()
+	 * @deprecated deprecated in favor of {@link #getParameterValidationResults()}
 	 */
-	List<ParameterValidationResult> getAllValidationResults();
+	@Deprecated(since = "6.2", forRemoval = true)
+	default List<ParameterValidationResult> getAllValidationResults() {
+		return getParameterValidationResults();
+	}
 
 	/**
-	 * Return the subset of {@link #getAllValidationResults() allValidationResults}
+	 * Return the subset of {@link #getParameterValidationResults() allValidationResults}
 	 * that includes method parameters with validation errors directly on method
 	 * argument values. This excludes {@link #getBeanResults() beanResults} with
 	 * nested errors on their fields and properties.
 	 */
 	default List<ParameterValidationResult> getValueResults() {
-		return getAllValidationResults().stream()
+		return getParameterValidationResults().stream()
 				.filter(result -> !(result instanceof ParameterErrors))
 				.toList();
 	}
 
 	/**
-	 * Return the subset of {@link #getAllValidationResults() allValidationResults}
+	 * Return the subset of {@link #getParameterValidationResults() allValidationResults}
 	 * that includes Object method parameters with nested errors on their fields
 	 * and properties. This excludes {@link #getValueResults() valueResults} with
 	 * validation errors directly on method arguments.
 	 */
 	default List<ParameterErrors> getBeanResults() {
-		return getAllValidationResults().stream()
+		return getParameterValidationResults().stream()
 				.filter(ParameterErrors.class::isInstance)
 				.map(result -> (ParameterErrors) result)
 				.toList();
 	}
 
+	/**
+	 * Return errors from cross-parameter validation.
+	 * @since 6.2
+	 */
+	List<MessageSourceResolvable> getCrossParameterValidationResults();
+
 
 	/**
 	 * Factory method to create a {@link MethodValidationResult} instance.
@@ -112,7 +134,23 @@ public interface MethodValidationResult {
 	 * @return the created instance
 	 */
 	static MethodValidationResult create(Object target, Method method, List<ParameterValidationResult> results) {
-		return new DefaultMethodValidationResult(target, method, results);
+		return create(target, method, results, Collections.emptyList());
+	}
+
+	/**
+	 * Factory method to create a {@link MethodValidationResult} instance.
+	 * @param target the target Object
+	 * @param method the target method
+	 * @param results method validation results, expected to be non-empty
+	 * @param crossParameterErrors cross-parameter validation errors
+	 * @return the created instance
+	 * @since 6.2
+	 */
+	static MethodValidationResult create(
+			Object target, Method method, List<ParameterValidationResult> results,
+			List<MessageSourceResolvable> crossParameterErrors) {
+
+		return new DefaultMethodValidationResult(target, method, results, crossParameterErrors);
 	}
 
 	/**

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

@@ -16,18 +16,27 @@
 
 package org.springframework.validation.beanvalidation;
 
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
 import java.lang.reflect.Method;
 import java.util.List;
 import java.util.Locale;
 import java.util.Set;
 import java.util.function.Consumer;
 
+import jakarta.validation.Constraint;
+import jakarta.validation.ConstraintValidator;
+import jakarta.validation.ConstraintValidatorContext;
 import jakarta.validation.ConstraintViolation;
+import jakarta.validation.Payload;
 import jakarta.validation.Valid;
 import jakarta.validation.constraints.Max;
 import jakarta.validation.constraints.Min;
 import jakarta.validation.constraints.NotBlank;
 import jakarta.validation.constraints.Size;
+import jakarta.validation.constraintvalidation.SupportedValidationTarget;
+import jakarta.validation.constraintvalidation.ValidationTarget;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -40,6 +49,9 @@ import org.springframework.validation.method.MethodValidationResult;
 import org.springframework.validation.method.ParameterErrors;
 import org.springframework.validation.method.ParameterValidationResult;
 
+import static java.lang.annotation.ElementType.CONSTRUCTOR;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
@@ -77,7 +89,7 @@ class MethodValidationAdapterTests {
 
 		testArgs(target, method, new Object[] {faustino1234, cayetana6789, 3}, ex -> {
 
-			assertThat(ex.getAllValidationResults()).hasSize(3);
+			assertThat(ex.getParameterValidationResults()).hasSize(3);
 
 			assertBeanResult(ex.getBeanResults().get(0), 0, "student", faustino1234, List.of("""
 				Field error in object 'student' on field 'name': rejected value [Faustino1234]; \
@@ -117,7 +129,7 @@ class MethodValidationAdapterTests {
 
 		testArgs(target, method, new Object[] {faustino1234, new Person("Joe", List.of()), 1}, ex -> {
 
-			assertThat(ex.getAllValidationResults()).hasSize(1);
+			assertThat(ex.getParameterValidationResults()).hasSize(1);
 
 			assertBeanResult(ex.getBeanResults().get(0), 0, "studentToAdd", faustino1234, List.of("""
 				Field error in object 'studentToAdd' on field 'name': rejected value [Faustino1234]; \
@@ -134,7 +146,7 @@ class MethodValidationAdapterTests {
 
 		testReturnValue(target, getMethod(target, "getIntValue"), 4, ex -> {
 
-			assertThat(ex.getAllValidationResults()).hasSize(1);
+			assertThat(ex.getParameterValidationResults()).hasSize(1);
 
 			assertValueResult(ex.getValueResults().get(0), -1, 4, List.of("""
 				org.springframework.validation.beanvalidation.MethodValidationAdapter$ViolationMessageSourceResolvable: \
@@ -151,7 +163,7 @@ class MethodValidationAdapterTests {
 
 		testReturnValue(target, getMethod(target, "getPerson"), faustino1234, ex -> {
 
-			assertThat(ex.getAllValidationResults()).hasSize(1);
+			assertThat(ex.getParameterValidationResults()).hasSize(1);
 
 			assertBeanResult(ex.getBeanResults().get(0), -1, "person", faustino1234, List.of("""
 				Field error in object 'person' on field 'name': rejected value [Faustino1234]; \
@@ -169,7 +181,7 @@ class MethodValidationAdapterTests {
 
 		testArgs(target, method, new Object[] {List.of(faustino1234, cayetana6789)}, ex -> {
 
-			assertThat(ex.getAllValidationResults()).hasSize(2);
+			assertThat(ex.getParameterValidationResults()).hasSize(2);
 
 			int paramIndex = 0;
 			String objectName = "people";
@@ -203,7 +215,7 @@ class MethodValidationAdapterTests {
 		Method method = getMethod(target, "addHobbies");
 
 		testArgs(target, method, new Object[] {List.of("   ")}, ex -> {
-			assertThat(ex.getAllValidationResults()).hasSize(1);
+			assertThat(ex.getParameterValidationResults()).hasSize(1);
 			assertValueResult(ex.getValueResults().get(0), 0, "   ", List.of("""
 				org.springframework.validation.beanvalidation.MethodValidationAdapter$ViolationMessageSourceResolvable: \
 				codes [NotBlank.myService#addHobbies.hobbies,NotBlank.hobbies,NotBlank.java.util.List,NotBlank]; \
@@ -219,7 +231,7 @@ class MethodValidationAdapterTests {
 		Method method = getMethod(target, "addUniqueHobbies");
 
 		testArgs(target, method, new Object[] {Set.of("test", "   ")}, ex -> {
-			assertThat(ex.getAllValidationResults()).hasSize(1);
+			assertThat(ex.getParameterValidationResults()).hasSize(1);
 			assertValueResult(ex.getValueResults().get(0), 0, Set.of("test", "   "), List.of("""
 				org.springframework.validation.beanvalidation.MethodValidationAdapter$ViolationMessageSourceResolvable: \
 				codes [NotBlank.myService#addUniqueHobbies.hobbies,NotBlank.hobbies,NotBlank.java.util.Set,NotBlank]; \
@@ -229,6 +241,23 @@ class MethodValidationAdapterTests {
 		});
 	}
 
+	@Test
+	void validateCrossParams() {
+		MyService target = new MyService();
+		Method method = getMethod(target, "addRange");
+
+		testArgs(target, method, new Object[] {90, 50}, ex -> {
+			assertThat(ex.getParameterValidationResults()).isEmpty();
+			assertThat(ex.getCrossParameterValidationResults()).hasSize(1);
+			assertThat(ex.getCrossParameterValidationResults().get(0).toString()).isEqualTo("""
+					org.springframework.validation.beanvalidation.MethodValidationAdapter$ViolationMessageSourceResolvable: \
+					codes [RangeParams.myService#addRange,RangeParams]; \
+					arguments [org.springframework.context.support.DefaultMessageSourceResolvable: \
+					codes [myService#addRange]; \
+					arguments []; default message []]; default message [Invalid range]""");
+		});
+	}
+
 	private void testArgs(Object target, Method method, Object[] args, Consumer<MethodValidationResult> consumer) {
 		consumer.accept(this.validationAdapter.validateArguments(target, method, null, args, new Class<?>[0]));
 	}
@@ -294,6 +323,10 @@ class MethodValidationAdapterTests {
 
 		public void addUniqueHobbies(Set<@NotBlank String> hobbies) {
 		}
+
+		@RangeParams
+		public void addRange(int from, int to) {
+		}
 	}
 
 
@@ -301,4 +334,29 @@ class MethodValidationAdapterTests {
 	private record Person(@Size(min = 1, max = 10) String name, List<@NotBlank String> hobbies) {
 	}
 
+
+	@Documented
+	@Constraint(validatedBy = RangeParamsValidator.class)
+	@Target({ CONSTRUCTOR, METHOD })
+	@Retention(RUNTIME)
+	public @interface RangeParams {
+
+		String message() default "Invalid range";
+
+		Class<?>[] groups() default {};
+
+		Class<? extends Payload>[] payload() default {};
+
+	}
+
+
+	@SupportedValidationTarget(ValidationTarget.PARAMETERS)
+	public static final class RangeParamsValidator implements ConstraintValidator<RangeParams, Object[]> {
+
+		@Override
+		public boolean isValid(final Object[] parameters, final ConstraintValidatorContext context) {
+			return false;
+		}
+	}
+
 }

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

@@ -81,7 +81,7 @@ class MethodValidationProxyReactorTests {
 		StepVerifier.create(myService.addPerson(personMono))
 				.expectErrorSatisfies(t -> {
 					MethodValidationException ex = (MethodValidationException) t;
-					assertThat(ex.getAllValidationResults()).hasSize(1);
+					assertThat(ex.getParameterValidationResults()).hasSize(1);
 
 					ParameterErrors errors = ex.getBeanResults().get(0);
 					assertThat(errors.getErrorCount()).isEqualTo(1);

spring-web/src/main/java/org/springframework/web/method/annotation/HandlerMethodValidationException.java

@@ -22,6 +22,7 @@ import java.util.Locale;
 import java.util.function.Predicate;
 
 import org.springframework.context.MessageSource;
+import org.springframework.context.MessageSourceResolvable;
 import org.springframework.core.MethodParameter;
 import org.springframework.http.HttpStatus;
 import org.springframework.lang.Nullable;
@@ -107,8 +108,13 @@ public class HandlerMethodValidationException extends ResponseStatusException im
 	}
 
 	@Override
-	public List<ParameterValidationResult> getAllValidationResults() {
-		return this.validationResult.getAllValidationResults();
+	public List<ParameterValidationResult> getParameterValidationResults() {
+		return this.validationResult.getParameterValidationResults();
+	}
+
+	@Override
+	public List<MessageSourceResolvable> getCrossParameterValidationResults() {
+		return this.validationResult.getCrossParameterValidationResults();
 	}
 
 	/**
@@ -116,7 +122,7 @@ public class HandlerMethodValidationException extends ResponseStatusException im
 	 * through callback methods organized by controller method parameter type.
 	 */
 	public void visitResults(Visitor visitor) {
-		for (ParameterValidationResult result : getAllValidationResults()) {
+		for (ParameterValidationResult result : getParameterValidationResults()) {
 			MethodParameter param = result.getMethodParameter();
 			CookieValue cookieValue = param.getParameterAnnotation(CookieValue.class);
 			if (cookieValue != null) {

spring-web/src/main/java/org/springframework/web/method/annotation/HandlerMethodValidator.java

@@ -98,7 +98,7 @@ public final class HandlerMethodValidator implements MethodValidator {
 					}
 				}
 			}
-			if (result.getAllValidationResults().size() == bindingResultCount) {
+			if (result.getParameterValidationResults().size() == bindingResultCount) {
 				return;
 			}
 		}

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

@@ -208,7 +208,7 @@ class MethodValidationTests {
 					assertThat(this.jakartaValidator.getValidationCount()).isEqualTo(1);
 					assertThat(this.jakartaValidator.getMethodValidationCount()).isEqualTo(1);
 
-					assertThat(ex.getAllValidationResults()).hasSize(2);
+					assertThat(ex.getParameterValidationResults()).hasSize(2);
 
 					assertBeanResult(ex.getBeanResults().get(0), "student", Collections.singletonList(
 							"""
@@ -245,7 +245,7 @@ class MethodValidationTests {
 					assertThat(this.jakartaValidator.getValidationCount()).isEqualTo(1);
 					assertThat(this.jakartaValidator.getMethodValidationCount()).isEqualTo(1);
 
-					assertThat(ex.getAllValidationResults()).hasSize(2);
+					assertThat(ex.getParameterValidationResults()).hasSize(2);
 
 					assertBeanResult(ex.getBeanResults().get(0), "personList", Collections.singletonList(
 							"""

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

@@ -172,7 +172,7 @@ class MethodValidationTests {
 		assertThat(this.jakartaValidator.getValidationCount()).isEqualTo(1);
 		assertThat(this.jakartaValidator.getMethodValidationCount()).isEqualTo(1);
 
-		assertThat(ex.getAllValidationResults()).hasSize(2);
+		assertThat(ex.getParameterValidationResults()).hasSize(2);
 
 		assertBeanResult(ex.getBeanResults().get(0), "student", List.of("""
 			Field error in object 'student' on field 'name': rejected value [name=Faustino1234]; \
@@ -227,7 +227,7 @@ class MethodValidationTests {
 		assertThat(this.jakartaValidator.getValidationCount()).isEqualTo(1);
 		assertThat(this.jakartaValidator.getMethodValidationCount()).isEqualTo(1);
 
-		assertThat(ex.getAllValidationResults()).hasSize(2);
+		assertThat(ex.getParameterValidationResults()).hasSize(2);
 
 		assertBeanResult(ex.getBeanResults().get(0), "personList", List.of("""
 			Field error in object 'personList' on field 'name': rejected value [Faustino1234]; \