Mark response errors from @ExceptionHandler as handled

Also fix a couple of related issues:
- add AsyncRequestNotUsableException to the list of exceptions
that imply response issues.
- handle exceptions from @ExceptionHandler regardless of whether
thrown immediately or via Publisher.

Closes gh-32359

spring-web/src/main/java/org/springframework/web/util/DisconnectedClientHelper.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -39,7 +39,8 @@ public class DisconnectedClientHelper {
 			Set.of("broken pipe", "connection reset by peer");
 
 	private static final Set<String> EXCEPTION_TYPE_NAMES =
-			Set.of("AbortedException", "ClientAbortException", "EOFException", "EofException");
+			Set.of("AbortedException", "ClientAbortException",
+					"EOFException", "EofException", "AsyncRequestNotUsableException");
 
 	private final Log logger;
 

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerAdapter.java

@@ -307,21 +307,34 @@ private Mono<HandlerResult> handleException(
 				exceptions.toArray(arguments);  // efficient arraycopy call in ArrayList
 				arguments[arguments.length - 1] = handlerMethod;
 
-				return invocable.invoke(exchange, bindingContext, arguments);
+				return invocable.invoke(exchange, bindingContext, arguments)
+						.onErrorResume(invocationEx ->
+								handleExceptionHandlerFailure(exchange, exception, invocationEx, exceptions, invocable));
 			}
 			catch (Throwable invocationEx) {
-				if (!disconnectedClientHelper.checkAndLogClientDisconnectedException(invocationEx)) {
-					// Any other than the original exception (or a cause) is unintended here,
-					// probably an accident (e.g. failed assertion or the like).
-					if (!exceptions.contains(invocationEx) && logger.isWarnEnabled()) {
-						logger.warn(exchange.getLogPrefix() + "Failure in @ExceptionHandler " + invocable, invocationEx);
-					}
-				}
+				return handleExceptionHandlerFailure(exchange, exception, invocationEx, exceptions, invocable);
 			}
 		}
 		return Mono.error(exception);
 	}
 
+	private static Mono<HandlerResult> handleExceptionHandlerFailure(
+			ServerWebExchange exchange, Throwable exception, Throwable invocationEx,
+			ArrayList<Throwable> exceptions, InvocableHandlerMethod invocable) {
+
+		if (disconnectedClientHelper.checkAndLogClientDisconnectedException(invocationEx)) {
+			return Mono.empty();
+		}
+
+		// Any other than the original exception (or a cause) is unintended here,
+		// probably an accident (e.g. failed assertion or the like).
+		if (!exceptions.contains(invocationEx) && logger.isWarnEnabled()) {
+			logger.warn(exchange.getLogPrefix() + "Failure in @ExceptionHandler " + invocable, invocationEx);
+		}
+
+		return Mono.error(exception);
+	}
+
 	@Override
 	public Mono<HandlerResult> handleError(ServerWebExchange exchange, Throwable ex) {
 		return handleException(exchange, ex, null, null);

spring-webflux/src/test/java/org/springframework/web/reactive/DispatcherHandlerErrorTests.java

@@ -38,9 +38,11 @@
 import org.springframework.http.codec.ServerCodecConfigurer;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.context.request.async.AsyncRequestNotUsableException;
 import org.springframework.web.reactive.accept.HeaderContentTypeResolver;
 import org.springframework.web.reactive.handler.SimpleUrlHandlerMapping;
 import org.springframework.web.reactive.resource.ResourceWebHandler;
@@ -195,6 +197,14 @@ void webExceptionHandler() {
 		assertThat(exchange.getResponse().getStatusCode()).isEqualTo(HttpStatus.INTERNAL_SERVER_ERROR);
 	}
 
+	@Test
+	void asyncRequestNotUsableFromExceptionHandler() {
+		ServerWebExchange exchange = MockServerWebExchange.from(
+				MockServerHttpRequest.post("/request-not-usable-on-exception-handling"));
+
+		StepVerifier.create(this.dispatcherHandler.handle(exchange)).verifyComplete();
+	}
+
 
 	@Configuration
 	@SuppressWarnings({"unused", "WeakerAccess"})
@@ -249,6 +259,16 @@ public Foo unknownReturnType() {
 		public Publisher<String> requestBody(@RequestBody Publisher<String> body) {
 			return Mono.from(body).map(s -> "hello " + s);
 		}
+
+		@RequestMapping("/request-not-usable-on-exception-handling")
+		public void handle() throws Exception {
+			throw new IllegalAccessException();
+		}
+
+		@ExceptionHandler
+		public void handleException(IllegalAccessException ex) throws AsyncRequestNotUsableException {
+			throw new AsyncRequestNotUsableException("Simulated response failure");
+		}
 	}
 
 

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

@@ -432,12 +432,13 @@ protected ModelAndView doResolveHandlerMethodException(HttpServletRequest reques
 			exceptionHandlerMethod.invokeAndHandle(webRequest, mavContainer, arguments);
 		}
 		catch (Throwable invocationEx) {
-			if (!disconnectedClientHelper.checkAndLogClientDisconnectedException(invocationEx)) {
-				// Any other than the original exception (or a cause) is unintended here,
-				// probably an accident (e.g. failed assertion or the like).
-				if (!exceptions.contains(invocationEx) && logger.isWarnEnabled()) {
-					logger.warn("Failure in @ExceptionHandler " + exceptionHandlerMethod, invocationEx);
-				}
+			if (disconnectedClientHelper.checkAndLogClientDisconnectedException(invocationEx)) {
+				return new ModelAndView();
+			}
+			// Any other than the original exception (or a cause) is unintended here,
+			// probably an accident (e.g. failed assertion or the like).
+			if (!exceptions.contains(invocationEx) && logger.isWarnEnabled()) {
+				logger.warn("Failure in @ExceptionHandler " + exceptionHandlerMethod, invocationEx);
 			}
 			// Continue with default processing of the original exception...
 			return null;

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

@@ -24,6 +24,7 @@
 import java.util.Locale;
 
 import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServletResponse;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -50,6 +51,7 @@
 import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.bind.annotation.RestControllerAdvice;
+import org.springframework.web.context.request.async.AsyncRequestNotUsableException;
 import org.springframework.web.context.support.WebApplicationObjectSupport;
 import org.springframework.web.method.HandlerMethod;
 import org.springframework.web.method.annotation.ModelMethodProcessor;
@@ -65,6 +67,8 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.InstanceOfAssertFactories.LIST;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
 
 /**
  * Test fixture with {@link ExceptionHandlerExceptionResolver}.
@@ -401,6 +405,20 @@ void resolveExceptionViaMappedHandlerPredicate() throws Exception {
 		assertExceptionHandledAsBody(mav, "DefaultTestExceptionResolver: IllegalStateException");
 	}
 
+	@Test
+	void resolveExceptionAsyncRequestNotUsable() throws Exception {
+		HttpServletResponse response = mock();
+		given(response.getOutputStream()).willThrow(new AsyncRequestNotUsableException("Simulated I/O failure"));
+
+		IllegalArgumentException ex = new IllegalArgumentException();
+		HandlerMethod handlerMethod = new HandlerMethod(new ResponseBodyController(), "handle");
+		this.resolver.afterPropertiesSet();
+		ModelAndView mav = this.resolver.resolveException(this.request, response, handlerMethod, ex);
+
+		assertThat(mav).isNotNull();
+		assertThat(mav.isEmpty()).isTrue();
+	}
+
 
 	private void assertMethodProcessorCount(int resolverCount, int handlerCount) {
 		assertThat(this.resolver.getArgumentResolvers().getResolvers()).hasSize(resolverCount);