Fix BindingReflectionHintsRegistrar enum support

This commit prevents a StackOverflowError in
BindingReflectionHintsRegistrar when processing enum types
and refine related generated hints.

See spring-projectsgh-28683

Author: sdeleuze

spring-core/src/main/java/org/springframework/aot/hint/support/BindingReflectionHintsRegistrar.java

@@ -98,7 +98,8 @@ private void registerReflectionHints(ReflectionHints hints, Set<Type> seen, Type
 						PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
 						for (PropertyDescriptor propertyDescriptor : propertyDescriptors) {
 							Method writeMethod = propertyDescriptor.getWriteMethod();
-							if (writeMethod != null && writeMethod.getDeclaringClass() != Object.class) {
+							if (writeMethod != null && writeMethod.getDeclaringClass() != Object.class
+									&& writeMethod.getDeclaringClass() != Enum.class) {
 								hints.registerMethod(writeMethod, INVOKE);
 								MethodParameter methodParameter = MethodParameter.forExecutable(writeMethod, 0);
 								Type methodParameterType = methodParameter.getGenericParameterType();
@@ -107,7 +108,8 @@ private void registerReflectionHints(ReflectionHints hints, Set<Type> seen, Type
 								}
 							}
 							Method readMethod = propertyDescriptor.getReadMethod();
-							if (readMethod != null && readMethod.getDeclaringClass() != Object.class) {
+							if (readMethod != null && readMethod.getDeclaringClass() != Object.class
+									&& readMethod.getDeclaringClass() != Enum.class) {
 								hints.registerMethod(readMethod, INVOKE);
 								MethodParameter methodParameter = MethodParameter.forExecutable(readMethod, -1);
 								Type methodParameterType = methodParameter.getGenericParameterType();
@@ -144,7 +146,7 @@ private void collectReferencedTypes(Set<Type> seen, Set<Class<?>> types, @Nullab
 		}
 		ResolvableType resolvableType = ResolvableType.forType(type);
 		Class<?> clazz = resolvableType.resolve();
-		if (clazz != null) {
+		if (clazz != null && !types.contains(clazz)) {
 			types.add(clazz);
 			for (ResolvableType genericResolvableType : resolvableType.getGenerics()) {
 				collectReferencedTypes(seen, types, genericResolvableType.getType());

spring-core/src/test/java/org/springframework/aot/hint/support/BindingReflectionHintsRegistrarTests.java

@@ -196,6 +196,13 @@ void registerTypeForSerializationWithMultipleLevelsAndCollection() {
 				typeHint -> assertThat(typeHint.getType()).isEqualTo(TypeReference.of(Set.class)));
 	}
 
+	@Test
+	void registerTypeForSerializationWithEnum() {
+		bindingRegistrar.registerReflectionHints(this.hints.reflection(), SampleEnum.class);
+		assertThat(this.hints.reflection().typeHints()).singleElement()
+				.satisfies(typeHint -> assertThat(typeHint.getType()).isEqualTo(TypeReference.of(SampleEnum.class)));
+	}
+
 
 	static class SampleEmptyClass {
 	}
@@ -274,4 +281,8 @@ public String getString() {
 		}
 	}
 
+	enum SampleEnum {
+		value1, value2
+	}
+
 }