Failure to read AnnotatedField value in Jackson 2.11

[isaki]

I am reporting this issue for tracking purposes; I fully intend to submit a PR once I narrow down the root cause and come up with an acceptable fix.

Version Information

• Java: Corretto-11.0.7.10.1 (OpenJDK 11; macOS), OpenJDK 8u252 (Ubuntu 16 Server)
• Jackson: 2.11.1

Thankfully, this is failing in my unit tests on both my build environments so that makes this easy to debug.

com.fasterxml.jackson.databind.JsonMappingException: Failed to getValue() for field io.isaki.jsandbox.JacksonDatabindTest$DataParent#type: class com.fasterxml.jackson.databind.introspect.AnnotatedField cannot access a member of class io.isaki.jsandbox.JacksonDatabindTest$DataParent with modifiers "private final"
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._wrapAsIOE(DefaultSerializerProvider.java:509)
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:482)
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:319)
	at com.fasterxml.jackson.databind.ObjectMapper._configAndWriteValue(ObjectMapper.java:4374)
	at com.fasterxml.jackson.databind.ObjectMapper.writeValueAsString(ObjectMapper.java:3629)
	at io.isaki.jsandbox.JacksonDatabindTest.testAnnotatedField(JacksonDatabindTest.java:25)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
	at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
	at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
	at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
	at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:542)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:770)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:464)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:210)
Caused by: java.lang.IllegalArgumentException: Failed to getValue() for field io.isaki.jsandbox.JacksonDatabindTest$DataParent#type: class com.fasterxml.jackson.databind.introspect.AnnotatedField cannot access a member of class io.isaki.jsandbox.JacksonDatabindTest$DataParent with modifiers "private final"
	at com.fasterxml.jackson.databind.introspect.AnnotatedField.getValue(AnnotatedField.java:113)
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase._typeIdDef(BeanSerializerBase.java:717)
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeWithType(BeanSerializerBase.java:635)
	at com.fasterxml.jackson.databind.ser.impl.TypeWrappedSerializer.serialize(TypeWrappedSerializer.java:32)
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:480)
	... 30 more
Caused by: java.lang.IllegalAccessException: class com.fasterxml.jackson.databind.introspect.AnnotatedField cannot access a member of class io.isaki.jsandbox.JacksonDatabindTest$DataParent with modifiers "private final"
	at java.base/jdk.internal.reflect.Reflection.newIllegalAccessException(Reflection.java:361)
	at java.base/java.lang.reflect.AccessibleObject.checkAccess(AccessibleObject.java:591)
	at java.base/java.lang.reflect.Field.checkAccess(Field.java:1075)
	at java.base/java.lang.reflect.Field.get(Field.java:416)
	at com.fasterxml.jackson.databind.introspect.AnnotatedField.getValue(AnnotatedField.java:110)
	... 34 more

import static org.junit.Assert.assertEquals;

import java.util.Objects;

import org.junit.Test;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonSubTypes.Type;
import com.fasterxml.jackson.annotation.JsonTypeId;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonDatabindTest {

    @Test
    public void testAnnotatedField() throws JsonProcessingException {
        final DataParent test = new DataClassA();

        final ObjectMapper mapper = new ObjectMapper();
        final String json = mapper.writeValueAsString(test);

        final DataParent copy = mapper.readValue(json, DataParent.class);
        assertEquals(DataType.CLASS_A, copy.getType());
    }

    private enum DataType {
        CLASS_A;
    }

    @JsonAutoDetect(
        getterVisibility = JsonAutoDetect.Visibility.NONE,
        creatorVisibility = JsonAutoDetect.Visibility.NONE,
        isGetterVisibility = JsonAutoDetect.Visibility.NONE,
        fieldVisibility = JsonAutoDetect.Visibility.NONE,
        setterVisibility = JsonAutoDetect.Visibility.NONE)
    @JsonTypeInfo(
        use = JsonTypeInfo.Id.NAME,
        include = JsonTypeInfo.As.PROPERTY,
        property = "type",
        visible = true)
    @JsonSubTypes({
        @Type(name = "CLASS_A", value = DataClassA.class)
    })
    private static abstract class DataParent {

        @JsonProperty("type")
        @JsonTypeId
        private final DataType type;

        @SuppressWarnings("unused")
        DataParent() {
            super();
            this.type = null;
        }

        DataParent(final DataType type) {
            super();
            this.type = Objects.requireNonNull(type);
        }

        public final DataType getType() {
            return this.type;
        }
    }

    private static final class DataClassA extends DataParent {

        DataClassA() {
            super(DataType.CLASS_A);
        }
    }
}

EDIT: This test works fine with Jackson 2.9.10 (with 2.9.10.4).

[cowtowncoder]

Thank you for reporting this. It sounds like forcing of access is skipped for field type, when used as accessor for type id.

It seems bit odd that @JsonProperty is on private field, instead of public getType(), but usage as shown should work regardless.

[isaki]

This paradigm is common in the codebase I am working on; there are no setter methods. As such, it's easier to just place the annotations on the field directly so things are common between serialization and deserialization. Do you want me to take a stab at fixing it or do you already have a fix in mind?

[cowtowncoder]

Ok. I am just asking because in this case it would seem preferable that getter was used for value access; normally this would just work with naming convention but here @JsonAutoDetect is used to explicitly prevent that.

I do not have a fix in mind so feel free to propose a fix if that is easy enough to find.
I think the expected place would be in BeanSerializerBuilder.

[isaki]

Just as a heads up I have not forgotten about this; the library upgrades that update my dependency on Jackson from 2.9.10 to 2.11.1 got sidelined for a little bit for a pressing business need. I'll take care of this next week once I get this change out the door.

[cowtowncoder]

As per commit, added failing test from example above; might have a look to see if I can track down thge problem.

[cowtowncoder]

Looks like the problem is due to short-circuit in BeanSerializerBuilder.build(), in:

        if (_properties == null || _properties.isEmpty()) {
            if (_anyGetter == null && _objectIdWriter == null) {
                return null;
            }
            ...
        }
        // .... 
        if (_typeId != null) {   // force access
        }

which will prevent _typeId access from being forced (if allowed).
Will need to see if just moving the access forcing earlier is the way to go.

[cowtowncoder]

Fixed: specifically occurred only when there are no properties to write (not any-getter); will now modify access for typeId first (if any).

[isaki]

Wow, thanks! I appreciate the fix!