Unwrap XMLStreamException from cause

Closes: gh-24622

Author: rstoyanchev

spring-web/src/main/java/org/springframework/http/codec/xml/Jaxb2XmlDecoder.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.
@@ -197,6 +197,10 @@ public Object decode(DataBuffer dataBuffer, ResolvableType targetType,
 		catch (XMLStreamException ex) {
 			throw Exceptions.propagate(ex);
 		}
+		catch (Throwable ex) {
+			ex = (ex.getCause() instanceof XMLStreamException ? ex.getCause() : ex);
+			throw Exceptions.propagate(ex);
+		}
 		finally {
 			DataBufferUtils.release(dataBuffer);
 		}

spring-web/src/test/java/org/springframework/http/codec/xml/Jaxb2XmlDecoderTests.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.
@@ -19,11 +19,14 @@
 import java.nio.charset.StandardCharsets;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 
 import javax.xml.namespace.QName;
+import javax.xml.stream.XMLStreamException;
 import javax.xml.stream.events.XMLEvent;
 
 import org.junit.jupiter.api.Test;
+import reactor.core.Exceptions;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
@@ -66,6 +69,8 @@ public class Jaxb2XmlDecoderTests extends AbstractLeakCheckingTests {
 					"</pojo>" +
 					"<root/>";
 
+	private static final Map<String, Object> HINTS = Collections.emptyMap();
+
 
 	private final Jaxb2XmlDecoder decoder = new Jaxb2XmlDecoder();
 
@@ -88,8 +93,7 @@ public void canDecode() {
 
 	@Test
 	public void splitOneBranches() {
-		Flux<XMLEvent> xmlEvents = this.xmlEventDecoder
-				.decode(stringBuffer(POJO_ROOT), null, null, Collections.emptyMap());
+		Flux<XMLEvent> xmlEvents = this.xmlEventDecoder.decode(toDataBufferMono(POJO_ROOT), null, null, HINTS);
 		Flux<List<XMLEvent>> result = this.decoder.split(xmlEvents, new QName("pojo"));
 
 		StepVerifier.create(result)
@@ -109,9 +113,8 @@ public void splitOneBranches() {
 	}
 
 	@Test
-	public void splitMultipleBranches() throws Exception {
-		Flux<XMLEvent> xmlEvents = this.xmlEventDecoder
-				.decode(stringBuffer(POJO_CHILD), null, null, Collections.emptyMap());
+	public void splitMultipleBranches() {
+		Flux<XMLEvent> xmlEvents = this.xmlEventDecoder.decode(toDataBufferMono(POJO_CHILD), null, null, HINTS);
 		Flux<List<XMLEvent>> result = this.decoder.split(xmlEvents, new QName("pojo"));
 
 
@@ -158,10 +161,9 @@ private static void assertCharacters(XMLEvent event, String expectedData) {
 	}
 
 	@Test
-	public void decodeSingleXmlRootElement() throws Exception {
-		Mono<DataBuffer> source = stringBuffer(POJO_ROOT);
-		Mono<Object> output = this.decoder.decodeToMono(source, ResolvableType.forClass(Pojo.class),
-				null, Collections.emptyMap());
+	public void decodeSingleXmlRootElement() {
+		Mono<DataBuffer> source = toDataBufferMono(POJO_ROOT);
+		Mono<Object> output = this.decoder.decodeToMono(source, ResolvableType.forClass(Pojo.class), null, HINTS);
 
 		StepVerifier.create(output)
 				.expectNext(new Pojo("foofoo", "barbar"))
@@ -170,10 +172,9 @@ public void decodeSingleXmlRootElement() throws Exception {
 	}
 
 	@Test
-	public void decodeSingleXmlTypeElement() throws Exception {
-		Mono<DataBuffer> source = stringBuffer(POJO_ROOT);
-		Mono<Object> output = this.decoder.decodeToMono(source, ResolvableType.forClass(TypePojo.class),
-				null, Collections.emptyMap());
+	public void decodeSingleXmlTypeElement() {
+		Mono<DataBuffer> source = toDataBufferMono(POJO_ROOT);
+		Mono<Object> output = this.decoder.decodeToMono(source, ResolvableType.forClass(TypePojo.class), null, HINTS);
 
 		StepVerifier.create(output)
 				.expectNext(new TypePojo("foofoo", "barbar"))
@@ -182,10 +183,9 @@ public void decodeSingleXmlTypeElement() throws Exception {
 	}
 
 	@Test
-	public void decodeMultipleXmlRootElement() throws Exception {
-		Mono<DataBuffer> source = stringBuffer(POJO_CHILD);
-		Flux<Object> output = this.decoder.decode(source, ResolvableType.forClass(Pojo.class),
-				null, Collections.emptyMap());
+	public void decodeMultipleXmlRootElement() {
+		Mono<DataBuffer> source = toDataBufferMono(POJO_CHILD);
+		Flux<Object> output = this.decoder.decode(source, ResolvableType.forClass(Pojo.class), null, HINTS);
 
 		StepVerifier.create(output)
 				.expectNext(new Pojo("foo", "bar"))
@@ -195,10 +195,9 @@ public void decodeMultipleXmlRootElement() throws Exception {
 	}
 
 	@Test
-	public void decodeMultipleXmlTypeElement() throws Exception {
-		Mono<DataBuffer> source = stringBuffer(POJO_CHILD);
-		Flux<Object> output = this.decoder.decode(source, ResolvableType.forClass(TypePojo.class),
-				null, Collections.emptyMap());
+	public void decodeMultipleXmlTypeElement() {
+		Mono<DataBuffer> source = toDataBufferMono(POJO_CHILD);
+		Flux<Object> output = this.decoder.decode(source, ResolvableType.forClass(TypePojo.class), null, HINTS);
 
 		StepVerifier.create(output)
 				.expectNext(new TypePojo("foo", "bar"))
@@ -208,19 +207,27 @@ public void decodeMultipleXmlTypeElement() throws Exception {
 	}
 
 	@Test
-	public void decodeError() throws Exception {
+	public void decodeError() {
 		Flux<DataBuffer> source = Flux.concat(
-				stringBuffer("<pojo>"),
+				toDataBufferMono("<pojo>"),
 				Flux.error(new RuntimeException()));
 
-		Mono<Object> output = this.decoder.decodeToMono(source, ResolvableType.forClass(Pojo.class),
-				null, Collections.emptyMap());
+		Mono<Object> output = this.decoder.decodeToMono(source, ResolvableType.forClass(Pojo.class), null, HINTS);
 
 		StepVerifier.create(output)
 				.expectError(RuntimeException.class)
 				.verify();
 	}
 
+	@Test // gh-24622
+	public void decodeErrorWithXmlNotWellFormed() {
+		Mono<DataBuffer> source = toDataBufferMono("<Response><tag>something</tag</Response>");
+		Mono<Object> result = this.decoder.decodeToMono(source, ResolvableType.forClass(Pojo.class), null, HINTS);
+
+		StepVerifier.create(result).verifyErrorSatisfies(ex ->
+				assertThat(Exceptions.unwrap(ex)).isInstanceOf(XMLStreamException.class));
+	}
+
 	@Test
 	public void toExpectedQName() {
 		assertThat(this.decoder.toQName(Pojo.class)).isEqualTo(new QName("pojo"));
@@ -236,7 +243,7 @@ public void toExpectedQName() {
 
 	}
 
-	private Mono<DataBuffer> stringBuffer(String value) {
+	private Mono<DataBuffer> toDataBufferMono(String value) {
 		return Mono.defer(() -> {
 			byte[] bytes = value.getBytes(StandardCharsets.UTF_8);
 			DataBuffer buffer = this.bufferFactory.allocateBuffer(bytes.length);