Avoid infinite recursion in AOT processing with recursive generics

Author: scordio

Diff for: spring-context/src/main/java/org/springframework/validation/beanvalidation/BeanValidationBeanRegistrationAotProcessor.java

@@ -104,20 +104,24 @@ public static BeanRegistrationAotContribution processAheadOfTime(RegisteredBean
 			}
 
 			Class<?> beanClass = registeredBean.getBeanClass();
+			Set<Class<?>> visitedClasses = new HashSet<>();
 			Set<Class<?>> validatedClasses = new HashSet<>();
 			Set<Class<? extends ConstraintValidator<?, ?>>> constraintValidatorClasses = new HashSet<>();
 
-			processAheadOfTime(beanClass, validatedClasses, constraintValidatorClasses);
+			processAheadOfTime(beanClass, visitedClasses, validatedClasses, constraintValidatorClasses);
 
 			if (!validatedClasses.isEmpty() || !constraintValidatorClasses.isEmpty()) {
 				return new AotContribution(validatedClasses, constraintValidatorClasses);
 			}
 			return null;
 		}
 
-		private static void processAheadOfTime(Class<?> clazz, Collection<Class<?>> validatedClasses,
-				Collection<Class<? extends ConstraintValidator<?, ?>>> constraintValidatorClasses) {
+		private static void processAheadOfTime(Class<?> clazz, Set<Class<?>> visitedClasses, Set<Class<?>> validatedClasses,
+				Set<Class<? extends ConstraintValidator<?, ?>>> constraintValidatorClasses) {
 
+			if (visitedClasses.add(clazz)) {
+				return;
+			}
 			Assert.notNull(validator, "Validator can't be null");
 
 			BeanDescriptor descriptor;
@@ -149,12 +153,12 @@ else if (ex instanceof TypeNotPresentException) {
 
 			ReflectionUtils.doWithFields(clazz, field -> {
 				Class<?> type = field.getType();
-				if (Iterable.class.isAssignableFrom(type) || List.class.isAssignableFrom(type) || Optional.class.isAssignableFrom(type)) {
+				if (Iterable.class.isAssignableFrom(type) || Optional.class.isAssignableFrom(type)) {
 					ResolvableType resolvableType = ResolvableType.forField(field);
 					Class<?> genericType = resolvableType.getGeneric(0).toClass();
 					if (shouldProcess(genericType)) {
 						validatedClasses.add(clazz);
-						processAheadOfTime(genericType, validatedClasses, constraintValidatorClasses);
+						processAheadOfTime(genericType, visitedClasses, validatedClasses, constraintValidatorClasses);
 					}
 				}
 				if (Map.class.isAssignableFrom(type)) {
@@ -163,11 +167,11 @@ else if (ex instanceof TypeNotPresentException) {
 					Class<?> valueGenericType = resolvableType.getGeneric(1).toClass();
 					if (shouldProcess(keyGenericType)) {
 						validatedClasses.add(clazz);
-						processAheadOfTime(keyGenericType, validatedClasses, constraintValidatorClasses);
+						processAheadOfTime(keyGenericType, visitedClasses, validatedClasses, constraintValidatorClasses);
 					}
 					if (shouldProcess(valueGenericType)) {
 						validatedClasses.add(clazz);
-						processAheadOfTime(valueGenericType, validatedClasses, constraintValidatorClasses);
+						processAheadOfTime(valueGenericType, visitedClasses, validatedClasses, constraintValidatorClasses);
 					}
 				}
 			});

Diff for: spring-context/src/test/java/org/springframework/validation/beanvalidation/BeanValidationBeanRegistrationAotProcessorTests.java

@@ -22,6 +22,9 @@
 import java.lang.annotation.Target;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
 
 import jakarta.validation.Constraint;
 import jakarta.validation.ConstraintValidator;
@@ -32,6 +35,8 @@
 import org.hibernate.validator.internal.constraintvalidators.bv.PatternValidator;
 import org.junit.jupiter.api.Test;
 
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 import org.springframework.aot.generate.GenerationContext;
 import org.springframework.aot.hint.MemberCategory;
 import org.springframework.aot.hint.predicate.RuntimeHintsPredicates;
@@ -121,6 +126,13 @@ void shouldProcessTransitiveGenericTypeLevelConstraint() {
 				.withMemberCategory(MemberCategory.INVOKE_DECLARED_CONSTRUCTORS)).accepts(this.generationContext.getRuntimeHints());
 	}
 
+	@ParameterizedTest  // gh-33936
+	@ValueSource(classes = {BeanWithIterable.class, BeanWithMap.class, BeanWithOptional.class})
+	void shouldProcessRecursiveGenericsWithoutInfiniteRecursion(Class<?> beanClass) {
+		process(beanClass);
+		assertThat(this.generationContext.getRuntimeHints().reflection().typeHints()).hasSize(0);
+	}
+
 	private void process(Class<?> beanClass) {
 		BeanRegistrationAotContribution contribution = createContribution(beanClass);
 		if (contribution != null) {
@@ -244,4 +256,16 @@ public void setExclude(List<Exclude> exclude) {
 		}
 	}
 
+	static class BeanWithIterable {
+		private final Iterable<BeanWithIterable> beans = Set.of();
+	}
+
+	static class BeanWithMap {
+		private final Map<String, BeanWithMap> beans = Map.of();
+	}
+
+	static class BeanWithOptional {
+		private final Optional<BeanWithOptional> beans = Optional.empty();
+	}
+
 }