Custom deserializer with parent object update

[migel]

Hi, I have custom deserializer for DataA. An instance of DataA is contained in DataB, when updating an existing instance of DataB (as opposed to creating a new one) I get an exception when deserializing via a JsonNode object (deserializing via a String object works).

import java.io.IOException;

import org.junit.Assert;
import org.junit.Test;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
import com.fasterxml.jackson.databind.module.SimpleModule;

public class TestDeserTest {
    static class DataA {
        public int i = 1;
        public int j = 2;

    }

    static class DataB {
        public DataA da = new DataA();
        public int k = 3;
    }

    static class DataADeserializer extends StdDeserializer<DataA> {
        private static final long serialVersionUID = 1L;

        DataADeserializer() {
            super(DataA.class);
        }

        public DataA deserialize(JsonParser jp, DeserializationContext ctxt)
                throws JsonProcessingException, IOException {
            assert (jp.getCurrentToken() == JsonToken.START_OBJECT);
            JsonNode node = jp.getCodec().readTree(jp);

            DataA da = new DataA();
            da.i = 5;
            return da;
        }
    }

    @Test
    public void test() throws IOException {
        ObjectMapper mapper = new ObjectMapper();
        SimpleModule module = new SimpleModule();
        module.addDeserializer(DataA.class, new DataADeserializer());
        mapper.registerModule(module);

        DataB db = new DataB();
        db.da.i = 11;
        db.k = 13;
        String jsonBString = mapper.writeValueAsString(db);
        JsonNode jsonBNode = mapper.valueToTree(db);

        // create parent
        DataB dbNewViaString = mapper.readValue(jsonBString, DataB.class);
        Assert.assertEquals(5, dbNewViaString.da.i);
        Assert.assertEquals(13, dbNewViaString.k);

        DataB dbNewViaNode = mapper.treeToValue(jsonBNode, DataB.class);
        Assert.assertEquals(5, dbNewViaNode.da.i);
        Assert.assertEquals(13, dbNewViaNode.k);

        // update parent
        DataB dbUpdViaString = new DataB();
        DataB dbUpdViaNode = new DataB();

        Assert.assertEquals(1, dbUpdViaString.da.i);
        Assert.assertEquals(3, dbUpdViaString.k);
        mapper.readerForUpdating(dbUpdViaString).readValue(jsonBString);
        Assert.assertEquals(5, dbUpdViaString.da.i);
        Assert.assertEquals(13, dbUpdViaString.k);

        Assert.assertEquals(1, dbUpdViaNode.da.i);
        Assert.assertEquals(3, dbUpdViaNode.k);
        // FAILS HERE:
        mapper.readerForUpdating(dbUpdViaNode).readValue(jsonBNode);
        Assert.assertEquals(5, dbUpdViaNode.da.i);
        Assert.assertEquals(13, dbUpdViaNode.k);
    }
}

The trace:

com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "i" (class myorg.TestDeserTest$DataB), not marked as ignorable (2 known properties: "da", "k"])
 at [Source: N/A; line: -1, column: -1] (through reference chain: myorg.DataB["da"]->myorg.DataB["i"])
    at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:51)
    at com.fasterxml.jackson.databind.DeserializationContext.reportUnknownProperty(DeserializationContext.java:817)
    at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:954)
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1324)
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1302)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:249)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:136)
    at com.fasterxml.jackson.databind.ObjectReader._bindAsTree(ObjectReader.java:1478)
    at com.fasterxml.jackson.databind.ObjectReader.readTree(ObjectReader.java:1020)
    at myorg.TestDeserTest$DataADeserializer.deserialize(TestDeserTest.java:39)
    at myorg.TestDeserTest$DataADeserializer.deserialize(TestDeserTest.java:1)
    at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:523)
    at com.fasterxml.jackson.databind.deser.impl.FieldProperty.deserializeAndSet(FieldProperty.java:101)
    at com.fasterxml.jackson.databind.deser.impl.BeanPropertyMap.findDeserializeAndSet(BeanPropertyMap.java:285)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:220)
    at com.fasterxml.jackson.databind.ObjectReader._bindAndClose(ObjectReader.java:1443)
    at com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:1154)
    at myorg.TestDeserTest.test(TestDeserTest.java:81)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

[cowtowncoder]

Interesting. I can reproduce it with given test case.

One thing I notice is that replacing jp.getCodec().readTree(jp) (or simpler equivalent of jp.readValueAsTree()) give the exception; but simple jp.skipChildren() does not.
So something in reading-as-tree is not working as expected...

[cowtowncoder]

Whoa. Internally it looks like JsonNode deserializer is resolved to be deserializer for DataA... wires getting crossed badly somewhere.

[cowtowncoder]

Actually, not problem with caching, but rather with _rootDeserializer that ObjectReader caches locally. Need to see how this can be by-passed.

[cowtowncoder]

Fixed in 2.5.3, although I did also backport it in 2.4.6 just in case.