Can not deserialize unwrapped list when `@JacksonXmlProperty` localName matches the parent's localName

[sandboxcoder]

Example code is here (requires Maven; simply run 'mvn test' to see the failure):
fullStackAngularSpringBoot.zip

Tested with latest 2.12.0-snapshot as of yesterday.

Below is the minimal xml it takes to expose the issue:

<main>
    <test>
        <test>
            <test>
            </test>
        </test>
    </test>
    <test>
    </test>
</main>

Where both main and test are very simple POJOs.

See Main.java:

import java.util.ArrayList;
import java.util.List;

import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

public class Main {
    @JacksonXmlProperty(localName = "test")
    @JacksonXmlElementWrapper(useWrapping = false)
    List<Test> list = new ArrayList<Test>();
}

Test.java:

import java.util.ArrayList;
import java.util.List;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

public class Test {
    @JacksonXmlProperty(localName = "test")
    @JacksonXmlElementWrapper(useWrapping = false)
    List<Test> list = new ArrayList<Test>();
}

Below is the exception:

[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[INFO] Running com.kreationsedge.demo.DemoApplicationTests
[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.294 s <<< FAILURE! - in com.kreationsedge.demo.DemoApplicationTests
[ERROR] contextLoads  Time elapsed: 0.292 s  <<< ERROR!
com.fasterxml.jackson.databind.JsonMappingException: Current state not XML_START_ELEMENT (1) but 2 (through reference chain: com.kreationsedge.demo.Main["test"]->java.util.ArrayList[0]->com.kreationsedge.demo.Test["test"]->java.util.ArrayList[0]->com.kreationsedge.demo.Test["test"]->java.util.ArrayList[0])
        at com.kreationsedge.demo.DemoApplicationTests.contextLoads(DemoApplicationTests.java:24)
Caused by: java.lang.IllegalStateException: Current state not XML_START_ELEMENT (1) but 2
        at com.kreationsedge.demo.DemoApplicationTests.contextLoads(DemoApplicationTests.java:24)

[INFO] 
[INFO] Results:
[INFO] 
[ERROR] Errors: 
[ERROR]   DemoApplicationTests.contextLoads:24 » JsonMapping Current state not XML_START...
[INFO] 
[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0
[INFO] 
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------

This issue is related to the other bug but the reporter closed the issue after he found a workaround. I'll probably end up doing the same to resolve our issue but it would be ideal if we could get this fix ported into 2.11 if possible. Thanks!

[cowtowncoder]

Interesting. This is not exactly the same as #86 as I actually added a fix for the problem case.
But looks like there may be an edge case that still results in similar problem, something getting out of sync. Input is bit different (the other case has attribute values, mapped to logical properties), which causes bit different token stream.

Thank you for reporting this case at any rate: it is important to tease out edge cases. Handling of unwrapped Lists is the major source of problems for this module.

[cowtowncoder]

Tricky. I think it's the empty List that was problem; code needs to avoid attempt to add virtual wrapping for those cases without failing. Fixed for 2.11(.1), 2.12.

[sandboxcoder]

Thanks a lot I just tested in my project and verified the fix worked. Thank you very much for hopping on this so quickly!

I'll be looking out for 2.11.1's release!