Deserialization xml with mixed unwraped array elements

I found a bug with deserialization unwrapped arrays.

If xml elements are ordered like:

<root>
    <arrayElement/>
    <otherProperty/>
    <arrayElement/>
</root>

then first <arrayElement/> is ignored and array contains the second element only.

jackson version: 2.9.3

---

I wrote the test case (sorry for using Lombok, I wanted to omit boilerplate code and do not write many equals methods).

POJO definition:

package com.example.xml;

import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
import lombok.AllArgsConstructor;
import lombok.Data;

import java.util.List;

@JacksonXmlRootElement
@Data
public class Root {

    @JacksonXmlProperty(localName = "cat")
    @JacksonXmlElementWrapper(useWrapping = false)
    public List<Cat> cats;

    @JacksonXmlProperty(localName = "dog")
    public Dog dogs;

    // Nested classes

    @Data
    @AllArgsConstructor
    public static class Dog {

        @JacksonXmlProperty(isAttribute = true)
        public String name;
    }

    @Data
    @AllArgsConstructor
    public static class Cat {

        @JacksonXmlProperty(isAttribute = true)
        public String name;
    }
}

Test class:

package com.example.xml;

import com.fasterxml.jackson.dataformat.xml.XmlMapper;
import org.junit.Test;
import java.util.ArrayList;
import static org.junit.Assert.assertEquals;

public class DeserializationTest {

    @Test
    public void contextLoads() throws Exception {
        Root actual = xmlMapper()
                .readValue(XML, Root.class);
        assertEquals(EXPECTED, actual);
    }

    private static final String XML = "<root>" +
                                      "    <cat name=\"first cat\"/>" +
                                      "    <dog name=\"first dog\"/>" +
                                      "    <cat name=\"second cat\"/>" +
                                      "</root>";

    private static final Root EXPECTED = new Root() {{
        cats = new ArrayList<Cat>() {{
            add(new Cat("first cat"));
            add(new Cat("second cat"));
        }};
        dogs = new Dog("first dog");
    }};

    private static XmlMapper xmlMapper() {
        final XmlMapper result = new XmlMapper();
        return result;
    }
}

Output:

java.lang.AssertionError: 
Expected :Root(cats=[Root.Cat(name=first cat), Root.Cat(name=second cat)], dogs=Root.Dog(name=first dog))
Actual   :Root(cats=[Root.Cat(name=second cat)], dogs=Root.Dog(name=first dog))

As you can see, first cat is absent in deserialized object.

---

I saw #201, but it is not this bug about.

[slavniyteo]

I looked inside.

I think the problem is that MethodProperty.deserializeAndSet uses method CollectionDeserializer.deserialize(JsonParser, DeserializationContext) but not CollectionDeserializer.deserialize(JsonParser, DeserializationContext, Collection<Object>).

If i expicity define setter which accumulates all passed values (not just sets field), all works.

// <..>
public class Root {
//<..>
    @JacksonXmlProperty(localName = "cat")
    @JacksonXmlElementWrapper(useWrapping = false)
    private List<Cat> cats;

    public void setCats(List<Cat> value){
        if (cats == null){
            cats = new ArrayList<Cat>(value.size());
        }
        cats.addAll(value);
    }
//<..>
}

So this is a workaround.

[cowtowncoder]

@naXa777 Jackson does not ignore unwrapped lists when using

@JacksonXmlElementWrapper(useWrapping = false)

annotation.