Expose all exception causes as provided handler method arguments

Closes gh-26317

Author: jhoeller

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ExceptionHandlerExceptionResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -410,24 +410,27 @@ protected ModelAndView doResolveHandlerMethodException(HttpServletRequest reques
 		ServletWebRequest webRequest = new ServletWebRequest(request, response);
 		ModelAndViewContainer mavContainer = new ModelAndViewContainer();
 
+		ArrayList<Throwable> exceptions = new ArrayList<>();
 		try {
 			if (logger.isDebugEnabled()) {
 				logger.debug("Using @ExceptionHandler " + exceptionHandlerMethod);
 			}
-			Throwable cause = exception.getCause();
-			if (cause != null) {
-				// Expose cause as provided argument as well
-				exceptionHandlerMethod.invokeAndHandle(webRequest, mavContainer, exception, cause, handlerMethod);
-			}
-			else {
-				// Otherwise, just the given exception as-is
-				exceptionHandlerMethod.invokeAndHandle(webRequest, mavContainer, exception, handlerMethod);
+			// Expose causes as provided arguments as well
+			Throwable exToExpose = exception;
+			while (exToExpose != null) {
+				exceptions.add(exToExpose);
+				Throwable cause = exToExpose.getCause();
+				exToExpose = (cause != exToExpose ? cause : null);
 			}
+			Object[] arguments = new Object[exceptions.size() + 1];
+			exceptions.toArray(arguments);  // efficient arraycopy call in ArrayList
+			arguments[arguments.length - 1] = handlerMethod;
+			exceptionHandlerMethod.invokeAndHandle(webRequest, mavContainer, arguments);
 		}
 		catch (Throwable invocationEx) {
-			// Any other than the original exception (or its cause) is unintended here,
+			// Any other than the original exception (or a cause) is unintended here,
 			// probably an accident (e.g. failed assertion or the like).
-			if (invocationEx != exception && invocationEx != exception.getCause() && logger.isWarnEnabled()) {
+			if (!exceptions.contains(invocationEx) && logger.isWarnEnabled()) {
 				logger.warn("Failure in @ExceptionHandler " + exceptionHandlerMethod, invocationEx);
 			}
 			// Continue with default processing of the original exception...

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -66,6 +66,7 @@
  * @author Arjen Poutsma
  * @author Kazuki Shimizu
  * @author Brian Clozel
+ * @author Rodolphe Lecocq
  * @since 3.1
  */
 @SuppressWarnings("unused")
@@ -189,6 +190,18 @@ void resolveExceptionResponseBody() throws UnsupportedEncodingException, NoSuchM
 		assertThat(this.response.getContentAsString()).isEqualTo("IllegalArgumentException");
 	}
 
+	@Test  // gh-26317
+	void resolveExceptionResponseBodyMatchingCauseLevel2() throws UnsupportedEncodingException, NoSuchMethodException {
+		Exception ex = new Exception(new Exception(new IllegalArgumentException()));
+		HandlerMethod handlerMethod = new HandlerMethod(new ResponseBodyController(), "handle");
+		this.resolver.afterPropertiesSet();
+		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handlerMethod, ex);
+
+		assertThat(mav).isNotNull();
+		assertThat(mav.isEmpty()).isTrue();
+		assertThat(this.response.getContentAsString()).isEqualTo("IllegalArgumentException");
+	}
+
 	@Test
 	void resolveExceptionResponseWriter() throws Exception {
 		IllegalArgumentException ex = new IllegalArgumentException();
@@ -257,6 +270,21 @@ void resolveExceptionGlobalHandlerOrdered() throws Exception {
 		assertThat(this.response.getContentAsString()).isEqualTo("TestExceptionResolver: IllegalStateException");
 	}
 
+	@Test  // gh-26317
+	void resolveExceptionGlobalHandlerOrderedMatchingCauseLevel2() throws Exception {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(MyConfig.class);
+		this.resolver.setApplicationContext(ctx);
+		this.resolver.afterPropertiesSet();
+
+		Exception ex = new Exception(new Exception(new IllegalStateException()));
+		HandlerMethod handlerMethod = new HandlerMethod(new ResponseBodyController(), "handle");
+		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handlerMethod, ex);
+
+		assertThat(mav).as("Exception was not handled").isNotNull();
+		assertThat(mav.isEmpty()).isTrue();
+		assertThat(this.response.getContentAsString()).isEqualTo("TestExceptionResolver: IllegalStateException");
+	}
+
 	@Test  // SPR-12605
 	void resolveExceptionWithHandlerMethodArg() throws Exception {
 		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(MyConfig.class);
@@ -294,14 +322,15 @@ void resolveExceptionWithAssertionErrorAsRootCause() throws Exception {
 		this.resolver.setApplicationContext(ctx);
 		this.resolver.afterPropertiesSet();
 
-		AssertionError err = new AssertionError("argh");
-		FatalBeanException ex = new FatalBeanException("wrapped", err);
+		AssertionError rootCause = new AssertionError("argh");
+		FatalBeanException cause = new FatalBeanException("wrapped", rootCause);
+		Exception ex = new Exception(cause);  // gh-26317
 		HandlerMethod handlerMethod = new HandlerMethod(new ResponseBodyController(), "handle");
 		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handlerMethod, ex);
 
 		assertThat(mav).as("Exception was not handled").isNotNull();
 		assertThat(mav.isEmpty()).isTrue();
-		assertThat(this.response.getContentAsString()).isEqualTo(err.toString());
+		assertThat(this.response.getContentAsString()).isEqualTo(rootCause.toString());
 	}
 
 	@Test
@@ -319,6 +348,21 @@ void resolveExceptionControllerAdviceHandler() throws Exception {
 		assertThat(this.response.getContentAsString()).isEqualTo("BasePackageTestExceptionResolver: IllegalStateException");
 	}
 
+	@Test  // gh-26317
+	void resolveExceptionControllerAdviceHandlerMatchingCauseLevel2() throws Exception {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(MyControllerAdviceConfig.class);
+		this.resolver.setApplicationContext(ctx);
+		this.resolver.afterPropertiesSet();
+
+		Exception ex = new Exception(new IllegalStateException());
+		HandlerMethod handlerMethod = new HandlerMethod(new ResponseBodyController(), "handle");
+		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handlerMethod, ex);
+
+		assertThat(mav).as("Exception was not handled").isNotNull();
+		assertThat(mav.isEmpty()).isTrue();
+		assertThat(this.response.getContentAsString()).isEqualTo("BasePackageTestExceptionResolver: IllegalStateException");
+	}
+
 	@Test
 	void resolveExceptionControllerAdviceNoHandler() throws Exception {
 		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(MyControllerAdviceConfig.class);