Fixed #374

Author: cowtowncoder

release-notes/CREDITS-2.x

@@ -115,6 +115,12 @@ Jochen Schalanda (joschi@github)
 * Reported #318: XMLMapper fails to deserialize null (POJO reference) from blank tag
  (2.12.0)
 
+Ingo Wiarda (dewarim@github)
+
+* Reported #374: Deserialization fails with `XmlMapper` and
+  `DeserializationFeature.UNWRAP_ROOT_VALUE`
+ (2.12.0)
+
 Ghenadii Batalski (ghenadiibatalski@github)
 
 * Reported #377: `ToXmlGenerator` ignores `Base64Variant` while serializing `byte[]`

release-notes/VERSION-2.x

@@ -35,6 +35,8 @@ Project: jackson-dataformat-xml
  (reported by Jochen S)
 #319: Empty root tag into `List` deserialization bug
  (reported by Seatec13@github)
+#374: Deserialization fails with `XmlMapper` and `DeserializationFeature.UNWRAP_ROOT_VALUE`
+ (reported by Ingo W)
 #377: `ToXmlGenerator` ignores `Base64Variant` while serializing `byte[]`
  (reported by Ghenadii B)
 #390: Unexpected attribute at string fields causes extra objects to be

src/main/java/com/fasterxml/jackson/dataformat/xml/deser/XmlDeserializationContext.java

@@ -77,6 +77,24 @@ public DefaultDeserializationContext with(DeserializerFactory factory) {
     /**********************************************************
      */
 
+    // [dataformat-xml#374]: need to remove handling of expected root name unwrapping
+    // to match serialization
+    @Override // since 2.12
+    public Object readRootValue(JsonParser p, JavaType valueType,
+            JsonDeserializer<Object> deser, Object valueToUpdate)
+        throws IOException
+    {
+//        if (_config.useRootWrapping()) {
+//            return _unwrapAndDeserialize(p, valueType, deser, valueToUpdate);
+//        }
+        if (valueToUpdate == null) {
+            return deser.deserialize(p, this);
+        }
+        return deser.deserialize(p, this, valueToUpdate);
+    }
+
+    // To support case where XML element has attributes as well as CDATA, need
+    // to "extract" scalar value (CDATA), after the fact
     @Override // since 2.12
     public String extractScalarFromObject(JsonParser p, JsonDeserializer<?> deser,
             Class<?> scalarType)

src/main/java/com/fasterxml/jackson/dataformat/xml/ser/XmlSerializerProvider.java

@@ -29,12 +29,6 @@ public class XmlSerializerProvider extends DefaultSerializerProvider
     // As of 2.7
     private static final long serialVersionUID = 1L;
 
-    /**
-     * If all we get to serialize is a null, there's no way to figure out
-     * expected root name; so let's just default to literal {@code "null"}.
-     */
-    protected final static QName ROOT_NAME_FOR_NULL = new QName("null");
-
     protected final XmlRootNameLookup _rootNameLookup;
 
     public XmlSerializerProvider(XmlRootNameLookup rootNames)
@@ -218,20 +212,20 @@ public void serializePolymorphic(JsonGenerator gen, Object value, JavaType rootT
         }
     }
 
-    protected void _serializeXmlNull(JsonGenerator jgen) throws IOException
+    protected void _serializeXmlNull(JsonGenerator gen) throws IOException
     {
         // 14-Nov-2016, tatu: As per [dataformat-xml#213], we may have explicitly
         //    configured root name...
         QName rootName = _rootNameFromConfig();
         if (rootName == null) {
-            rootName = ROOT_NAME_FOR_NULL;
+            rootName = XmlRootNameLookup.ROOT_NAME_FOR_NULL;
         }
-        if (jgen instanceof ToXmlGenerator) {
-            _initWithRootName((ToXmlGenerator) jgen, rootName);
+        if (gen instanceof ToXmlGenerator) {
+            _initWithRootName((ToXmlGenerator) gen, rootName);
         }
-        super.serializeValue(jgen, null);
+        super.serializeValue(gen, null);
     }
-    
+
     protected void _startRootArray(ToXmlGenerator xgen, QName rootName) throws IOException
     {
         xgen.writeStartObject();
@@ -241,10 +235,8 @@ protected void _startRootArray(ToXmlGenerator xgen, QName rootName) throws IOExc
 
     protected void _initWithRootName(ToXmlGenerator xgen, QName rootName) throws IOException
     {
-        /* 28-Nov-2012, tatu: We should only initialize the root
-         *  name if no name has been set, as per [dataformat-xml#42],
-         *  to allow for custom serializers to work.
-         */
+        // 28-Nov-2012, tatu: We should only initialize the root name if no name has been
+        //   set, as per [dataformat-xml#42], to allow for custom serializers to work.
         if (!xgen.setNextNameIfMissing(rootName)) {
             // however, if we are root, we... insist
             if (xgen.inRoot()) {

src/main/java/com/fasterxml/jackson/dataformat/xml/util/XmlRootNameLookup.java

@@ -18,6 +18,12 @@ public class XmlRootNameLookup
 {
     private static final long serialVersionUID = 1L;
 
+    /**
+     * If all we get to serialize is a null, there's no way to figure out
+     * expected root name; so let's just default to literal {@code "null"}.
+     */
+    public final static QName ROOT_NAME_FOR_NULL = new QName("null");
+
     /**
      * For efficient operation, let's try to minimize number of times we
      * need to introspect root element name to use.

src/test/java/com/fasterxml/jackson/dataformat/xml/failing/EnumIssue9Test.java

@@ -2,8 +2,6 @@
 
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
 
-import com.fasterxml.jackson.databind.ObjectMapper;
-
 import com.fasterxml.jackson.dataformat.xml.XmlMapper;
 import com.fasterxml.jackson.dataformat.xml.XmlTestBase;
 
@@ -29,14 +27,13 @@ public UntypedEnumBean() { }
     /**********************************************************
      */
 
-    private final XmlMapper MAPPER = new XmlMapper();
-    
+    private final XmlMapper MAPPER = newMapper();
+
     public void testUntypedEnum() throws Exception
     {
-        ObjectMapper mapper = new XmlMapper();
-        String xml = mapper.writeValueAsString(new UntypedEnumBean(TestEnum.B));
+        String xml = MAPPER.writeValueAsString(new UntypedEnumBean(TestEnum.B));
 
-        UntypedEnumBean result = mapper.readValue(xml, UntypedEnumBean.class);
+        UntypedEnumBean result = MAPPER.readValue(xml, UntypedEnumBean.class);
         assertNotNull(result);
         assertNotNull(result.value);
         Object ob = result.value;

src/test/java/com/fasterxml/jackson/dataformat/xml/failing/Issue37AdapterTest.java

@@ -13,6 +13,9 @@
 import com.fasterxml.jackson.dataformat.xml.*;
 import com.fasterxml.jackson.dataformat.xml.jaxb.XmlJaxbAnnotationIntrospector;
 
+// 30-Jun-2020, tatu: This is deferred and possibly won't be fixed
+//   at all. But leaving failing test here just in case future brings
+//   alternate approach to do something.
 public class Issue37AdapterTest extends XmlTestBase
 {
     @XmlJavaTypeAdapter(URLEncoderMapDataAdapter.class)

src/test/java/com/fasterxml/jackson/dataformat/xml/failing/Unwrapped374Test.java renamed to src/test/java/com/fasterxml/jackson/dataformat/xml/misc/RootNameWrapping374Test.java

@@ -1,12 +1,12 @@
-package com.fasterxml.jackson.dataformat.xml.failing;
+package com.fasterxml.jackson.dataformat.xml.misc;
 
 import com.fasterxml.jackson.annotation.JsonRootName;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.dataformat.xml.*;
 import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
 
-public class Unwrapped374Test extends XmlTestBase
+public class RootNameWrapping374Test extends XmlTestBase
 {
     @JacksonXmlRootElement(localName = "Root")
     @JsonRootName("Root")