Expose parameter annotations from interfaces across entire class hierarchy

Closes gh-24127

Author: jhoeller

spring-web/src/main/java/org/springframework/web/method/HandlerMethod.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -339,7 +339,7 @@ private List<Annotation[][]> getInterfaceParameterAnnotations() {
 		List<Annotation[][]> parameterAnnotations = this.interfaceParameterAnnotations;
 		if (parameterAnnotations == null) {
 			parameterAnnotations = new ArrayList<>();
-			for (Class<?> ifc : this.method.getDeclaringClass().getInterfaces()) {
+			for (Class<?> ifc : ClassUtils.getAllInterfacesForClassAsSet(this.method.getDeclaringClass())) {
 				for (Method candidate : ifc.getMethods()) {
 					if (isOverrideFor(candidate)) {
 						parameterAnnotations.add(candidate.getParameterAnnotations());

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -703,6 +703,27 @@ public void resolveArgumentTypeVariableWithGenericInterface() throws Exception {
 
 		RequestResponseBodyMethodProcessor processor = new RequestResponseBodyMethodProcessor(converters);
 
+		assertTrue(processor.supportsParameter(methodParameter));
+		String value = (String) processor.readWithMessageConverters(
+				this.request, methodParameter, methodParameter.getGenericParameterType());
+		assertEquals("foo", value);
+	}
+
+	@Test  // gh-24127
+	public void resolveArgumentTypeVariableWithGenericInterfaceAndSubclass() throws Exception {
+		this.servletRequest.setContent("\"foo\"".getBytes("UTF-8"));
+		this.servletRequest.setContentType(MediaType.APPLICATION_JSON_UTF8_VALUE);
+
+		Method method = SubControllerImplementingInterface.class.getMethod("handle", Object.class);
+		HandlerMethod handlerMethod = new HandlerMethod(new SubControllerImplementingInterface(), method);
+		MethodParameter methodParameter = handlerMethod.getMethodParameters()[0];
+
+		List<HttpMessageConverter<?>> converters = new ArrayList<>();
+		converters.add(new MappingJackson2HttpMessageConverter());
+
+		RequestResponseBodyMethodProcessor processor = new RequestResponseBodyMethodProcessor(converters);
+
+		assertTrue(processor.supportsParameter(methodParameter));
 		String value = (String) processor.readWithMessageConverters(
 				this.request, methodParameter, methodParameter.getGenericParameterType());
 		assertEquals("foo", value);
@@ -1055,4 +1076,13 @@ default A handle(@RequestBody A arg) {
 	static class MyControllerImplementingInterface implements MappingInterface<String> {
 	}
 
+
+	static class SubControllerImplementingInterface extends MyControllerImplementingInterface {
+
+		@Override
+		public String handle(String arg) {
+			return arg;
+		}
+	}
+
 }