JsonSetter(contentNulls = FAIL) is ignored in JsonCreator(DELEGATING) argument

[k163377]

Search before asking

• I searched in the issues and found nothing similar.

Describe the bug

I specified JsonSetter(contentNulls = FAIL) or SKIP in the constructor argument with JsonCreator(DELEGATING), but it was ignored.

Version Information

2.15.3

Reproduction

If other than DELEGATING, an InvalidNullException is thrown as expected.

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonSetter;
import com.fasterxml.jackson.annotation.Nulls;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.exc.InvalidNullException;
import org.junit.jupiter.api.Test;

import java.util.Map;

import static org.junit.jupiter.api.Assertions.assertThrows;

public class GitHubXXX {
    static class DelegatingWrapper {
        private final Map<String, String> value;

        @JsonCreator(mode = JsonCreator.Mode.DELEGATING)
        DelegatingWrapper(@JsonSetter(contentNulls = Nulls.FAIL) Map<String, String> value) {
            this.value = value;
        }

        public Map<String, String> getValue() {
            return value;
        }
    }

    @Test
    public void fails() {
        ObjectMapper mapper = new ObjectMapper();

        assertThrows(
                InvalidNullException.class,
                () -> mapper.readValue("{\"foo\":null}", DelegatingWrapper.class)
        );
    }

    static class SetterWrapper {
        private Map<String, String> value;

        public Map<String, String> getValue() {
            return value;
        }

        @JsonSetter(contentNulls = Nulls.FAIL)
        public void setValue(Map<String, String> value) {
            this.value = value;
        }
    }

    static class PropertiesWrapper {
        private final Map<String, String> value;

        @JsonCreator(mode = JsonCreator.Mode.PROPERTIES)
        PropertiesWrapper(
                @JsonSetter(contentNulls = Nulls.FAIL)
                @JsonProperty("value")
                Map<String, String> value
        ) {
            this.value = value;
        }

        public Map<String, String> getValue() {
            return value;
        }
    }

    static class DefaultWrapper {
        private final Map<String, String> value;

        @JsonCreator(mode = JsonCreator.Mode.DEFAULT)
        DefaultWrapper(
                @JsonSetter(contentNulls = Nulls.FAIL)
                @JsonProperty("value")
                Map<String, String> value
        ) {
            this.value = value;
        }

        public Map<String, String> getValue() {
            return value;
        }
    }

    @Test
    void valid() {
        ObjectMapper mapper = new ObjectMapper();

        assertThrows(
                InvalidNullException.class,
                () -> mapper.readValue("{\"value\":{\"foo\":null}}", SetterWrapper.class)
        );
        assertThrows(
                InvalidNullException.class,
                () -> mapper.readValue("{\"value\":{\"foo\":null}}", PropertiesWrapper.class)
        );
        assertThrows(
                InvalidNullException.class,
                () -> mapper.readValue("{\"value\":{\"foo\":null}}", DefaultWrapper.class)
        );
    }
}

Expected behavior

An InvalidNullException is thrown.

Additional context

Fixing this issue may make it easier to resolve FasterXML/jackson-module-kotlin#399.

[k163377]

I have debugged it and it seems that all parsing related to PropertyMetadata is skipped.

jackson-databind/src/main/java/com/fasterxml/jackson/databind/deser/BeanDeserializerBase.java

Lines 696 to 703 in 3a271be

	@SuppressWarnings("unchecked")
	private JsonDeserializer<Object> _findDelegateDeserializer(DeserializationContext ctxt,
	JavaType delegateType, AnnotatedWithParams delegateCreator) throws JsonMappingException
	{
	// Need to create a temporary property to allow contextual deserializers:
	BeanProperty.Std property = new BeanProperty.Std(TEMP_PROPERTY_NAME,
	delegateType, null, delegateCreator,
	PropertyMetadata.STD_OPTIONAL);

I could not fully check the path, but it seems that the parsing of the parameters was done before this process, so I personally think it is appropriate to copy the results of that process.

[JooHyukKim]

I tried debugging also, it seems like "value" field for DelegateWrapper is treated only as a field property and ContainerDeserializerBase._nullProvider is set to StringDeserializer.

[cowtowncoder]

This does sound like a bug, and not related to general challenge wrt Creator property detection (since there is explicit @JsonCreator annotation).

[cowtowncoder]

@k163377 is probably right in pointing that this is why annotations are not found -- there is no property accessor (Constructor/Factory method parameter declaration) being passed and a placeholder (with no annotations) is given.
This would prevent other annotations from being accessible similarly.

And why is it not being passed? It is not being retained during Creator collection process, it looks like.
Not sure how easy it'd be to add that plumbing, will have a look.

[cowtowncoder]

Hmmh. Access is via ValueInstantiator which only provides type information, not accessor.

I might just add a failing test for now.

[cowtowncoder]

Ok doh. I am blind. _findDelegateDeserializer() is directly passed the accessor. It need not be passed. :-)

But need to see how to change BeanProperty.Std to give/use necessary information.

[cowtowncoder]

Ok, phew. Was able to figure it out, relatively cleanly. Fix will be in 2.17.0 at least, although I guess I can double-check if this might be backportable.

[cowtowncoder]

Ok, and with that backporting to 2.16.1 worked fine.

[k163377]

Wow, thank you for even back porting.

[cowtowncoder]

No problem @k163377 -- I do it for safe fixes. Thank you for reporting this, pointing out where the problem is. Saved me lots of time.