Add reflection hints for data binding in Web controllers

Closes spring-projectsgh-28623

Author: sdeleuze

spring-web/src/main/java/org/springframework/web/bind/annotation/RequestMappingReflectiveProcessor.java

@@ -72,7 +72,8 @@ protected void registerParameterHints(ReflectionHints hints, Method method) {
 		hints.registerMethod(method, hint -> hint.setModes(ExecutableMode.INVOKE));
 		for (Parameter parameter : method.getParameters()) {
 			MethodParameter methodParameter = MethodParameter.forParameter(parameter);
-			if (methodParameter.hasParameterAnnotation(RequestBody.class)) {
+			if (methodParameter.hasParameterAnnotation(RequestBody.class) ||
+					methodParameter.hasParameterAnnotation(ModelAttribute.class)) {
 				this.bindingRegistrar.registerReflectionHints(hints, methodParameter.getGenericParameterType());
 			}
 			else if (HttpEntity.class.isAssignableFrom(methodParameter.getParameterType())) {

spring-web/src/test/java/org/springframework/web/bind/annotation/RequestMappingReflectiveProcessorTests.java

@@ -74,6 +74,24 @@ void registerReflectiveHintsForMethodWithRequestBody() throws NoSuchMethodExcept
 				typeHint -> assertThat(typeHint.getType()).isEqualTo(TypeReference.of(String.class)));
 	}
 
+	@Test
+	void registerReflectiveHintsForMethodWithModelAttribute() throws NoSuchMethodException {
+		Method method = SampleController.class.getDeclaredMethod("postForm", Request.class);
+		processor.registerReflectionHints(hints, method);
+		assertThat(hints.typeHints()).satisfiesExactlyInAnyOrder(
+				typeHint -> assertThat(typeHint.getType()).isEqualTo(TypeReference.of(SampleController.class)),
+				typeHint -> {
+					assertThat(typeHint.getType()).isEqualTo(TypeReference.of(Request.class));
+					assertThat(typeHint.getMemberCategories()).containsExactlyInAnyOrder(
+							MemberCategory.INVOKE_DECLARED_CONSTRUCTORS,
+							MemberCategory.DECLARED_FIELDS);
+					assertThat(typeHint.methods()).satisfiesExactlyInAnyOrder(
+							hint -> assertThat(hint.getName()).isEqualTo("getMessage"),
+							hint -> assertThat(hint.getName()).isEqualTo("setMessage"));
+				},
+				typeHint -> assertThat(typeHint.getType()).isEqualTo(TypeReference.of(String.class)));
+	}
+
 	@Test
 	void registerReflectiveHintsForMethodWithRestController() throws NoSuchMethodException {
 		Method method = SampleRestController.class.getDeclaredMethod("get");
@@ -177,6 +195,10 @@ Response get() {
 		void post(@RequestBody Request request) {
 		}
 
+		@PostMapping
+		void postForm(@ModelAttribute Request request) {
+		}
+
 		@GetMapping
 		@ResponseBody
 		String message() {