[BUG] @Jacksonized does not copy @JsonUnwrapped to @Builder

[mjustin]

Describe the bug

The @Jacksonized annotation says it "[copies] Jackson-related configuration annotations [...] from the class to the builder class." However, it does not copy the @JsonUnwrapped annotation, which results in incorrect deserialization behavior for objects that require it.

To Reproduce

ExampleFile.java

import com.fasterxml.jackson.annotation.JsonUnwrapped;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.json.JsonMapper;
import lombok.*;
import lombok.extern.jackson.Jacksonized;

public class ExampleFile {
    public static void main(String[] args) throws JsonProcessingException {
        ObjectMapper objectMapper = JsonMapper.builder().disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES).build();
        WithUnwrapped expected = new WithUnwrapped(new NestedValue("A", "B"));

        String json = "{\"value1\":\"A\",\"value2\":\"B\"}";
        WithUnwrapped deserializedObject = objectMapper.readValue(json, WithUnwrapped.class);
        if (!expected.equals(deserializedObject)) {
            throw new IllegalStateException("Wrong value; was: " + deserializedObject);
        }
    }

    @Data
    @NoArgsConstructor
    @AllArgsConstructor
    @Builder     // Correct result if these two annotations are commented out
    @Jacksonized // Correct result if these two annotations are commented out
    public static class WithUnwrapped {
        @JsonUnwrapped
        private NestedValue nested;
    }

    @Data
    @NoArgsConstructor
    @AllArgsConstructor
    public static class NestedValue {
        private String value1;

        private String value2;
    }
}

Reproduction Steps

$ curl -s https://repo1.maven.org/maven2/org/projectlombok/lombok/1.18.18/lombok-1.18.18.jar -O
$ curl -s https://repo1.maven.org/maven2/com/fasterxml/jackson/core/jackson-annotations/2.12.1/jackson-annotations-2.12.1.jar -O
$ curl -s https://repo1.maven.org/maven2/com/fasterxml/jackson/core/jackson-core/2.12.1/jackson-core-2.12.1.jar -O
$ curl -s https://repo1.maven.org/maven2/com/fasterxml/jackson/core/jackson-databind/2.12.1/jackson-databind-2.12.1.jar -O
$ javac -cp "*" ExampleFile.java
$ java -cp ".:*" ExampleFile
Exception in thread "main" java.lang.IllegalStateException: Wrong value; was: ExampleFile.WithUnwrapped(nested=null)
	at ExampleFile.main(ExampleFile.java:17)

Expected behavior

The @JsonUnwrapped annotation should be copied to the builder method. In the specific example above, this should lead to the JSON value successfully parsing.

Version info (please complete the following information):

• Lombok 1.18.18
• javac 11.0.9.1

[snystedt]

I have been facing the same issue with my use case and I took a look at the JacksonizedHandler.

It uses the array defined in HandlerUtils with the following members:

JACKSON_COPY_TO_BUILDER_ANNOTATIONS = Collections.unmodifiableList(Arrays.asList(new String[] {
			"com.fasterxml.jackson.annotation.JsonAutoDetect",
			"com.fasterxml.jackson.annotation.JsonFormat",
			"com.fasterxml.jackson.annotation.JsonIgnoreProperties",
			"com.fasterxml.jackson.annotation.JsonIgnoreType",
			"com.fasterxml.jackson.annotation.JsonPropertyOrder",
			"com.fasterxml.jackson.annotation.JsonRootName",
			"com.fasterxml.jackson.annotation.JsonSubTypes",
			"com.fasterxml.jackson.annotation.JsonTypeInfo",
			"com.fasterxml.jackson.annotation.JsonTypeName",
			"com.fasterxml.jackson.annotation.JsonView",
			"com.fasterxml.jackson.databind.annotation.JsonNaming",
		}));

Wouldn't the fix be as simple as adding "com.fasterxml.jackson.annotation.JsonUnwrapped" to this array?

[janrieke]

Probably not, because that list is for the builder class, not the setter methods. However, there's another list for that: COPY_TO_SETTER_ANNOTATIONS

[snystedt]

I just realized the sample above is a bit different from our case.

Our case is something like this:

@Builder
@Jacksonized
public class Foo {
    @JsonUnwrapped
    private Bar bar;
}

If I manually add a builder and annotate the Bar-method as JsonUnwrapped it works as expected.

@Builder
@JsonDeserialize(builder = Foo.FooBuilder.class)
public class Foo {
    @JsonUnwrapped
    private Bar bar;

    @JsonPOJOBuilder(withPrefix = "")
    public static class FooBuilder {
        private Bar bar;

        FooBuilder() {}
       
        @JsonUnwrapped
        public FooBuilder bar(Bar bar) {
            this.bar = bar;
            return this;
        }
        
        public Foo build() {
            return new Foo(bar);
        }
    }
}

In this case the suggestion above should be valid, right?

[snystedt]

Or is it that you mean to say that the JACKSON_COPY_TO_BUILDER_ANNOTATIONS enumerates the annotations that would end up on the actual Builder class and the COPY_TO_SETTER_ANNOTATIONS enumerates annotations that would end up on the actual setter method of the class (in the above case the public FooBuilder bar(Bar bar) {...})?

[janrieke]

Exactly.

[snystedt]

So, should I just make a branch and a PR?

[j-klemm]

Any updates on this @snystedt @janrieke ?

[rzwitserloot]

@snystedt I don't use any of these tools so I have to go by what you've all figured out. I don't know what @JsonUnwrapped is meant to do. However, if indeed it is the case that it should always be copied straight to the builder's 'setter' method if the field is annotated with it, then yeah, it's as simple as adding it to the list for the COPY_TO_SETTER_ANNOTATIONS file. If you're a new contributor, also add yourself to the AUTHORS file and that's all that's needed in the PR for this one I think.