MapStruct 1.3.0.Final produces uncompilable code when using Java 11 + Lombok 1.18.6

[DmitriiSolovev]

My setup: Java 11.02, Gradle 5.2.1, MapStruct 1.3.0.Final, Lombok 1.18.6 and Spring Boot 2.3.1.

build.gradle

plugins {
    id "net.ltgt.apt" version "0.21"
    id "net.ltgt.apt-idea" version "0.21"
}

...

/* Lombok */
compileOnly "org.projectlombok:lombok:${lombokVersion}"
annotationProcessor "org.projectlombok:lombok:${lombokVersion}"

/* Map Struct */
implementation "org.mapstruct:mapstruct-jdk8:${mapstructVersion}"
annotationProcessor "org.mapstruct:mapstruct-processor:${mapstructVersion}"
testAnnotationProcessor "org.mapstruct:mapstruct-processor:${mapstructVersion}"

FirstEntity.java

@Getter
@Setter
@Builder
@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode(of = "id")
@Entity
@Table(name="first_entity")
public class FirstEntity {

  @Id
  private Long id;

  @ManyToOne
  @JoinColumn(name="second_entity_id")
  private SecondEntity secondEntity;

}

FirstEntityDTO.java

@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class FirstEntityDTO {

  private Long id;
  private SecondEntityDTO secondEntity;

}

SecondEntity.java

@Getter
@Setter
@Builder
@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode(of = "id")
@Entity
@Table(name="second_entity")
public class SecondEntity {

  @Id
  private Long id;

}

SecondEntityDTO.java

@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class SecondEntityDTO {

  private Long id;

}

EntityMapper.java

@Mapper(
        unmappedTargetPolicy = ReportingPolicy.IGNORE,
        componentModel = "spring"
)
public interface EntityMapper {

    FirstEntity updateEntity(FirstEntityDTO entityDto, @MappingTarget FirstEntity entity);
}

Generated code, MapStruct 1.3.0.Final

if (entityDto.getSecondEntity() != null ) {
    if (entity.getSecondEntity() == null ) {
        entity.setSecondEntity( SecondEntity.builder() ); //compilation error: incompatible types
    }
    secondEntityDTOToSecondEntity( entityDto.getSecondEntity(), entity.getSecondEntity());
}

Generated code, MapStruct 1.2.0.Final

if (entityDto.getSecondEntity() != null ) {
    if (entity.getSecondEntity() == null ) {
        entity.setSecondEntity( new SecondEntity() ); //success
    }
    secondEntityDTOToSecondEntity( entityDto.getSecondEntity(), entity.getSecondEntity());
}

As a workaround, I use MapStruct 1.2.0.Final now.

[sjaakd]

2 questions..Have you looked at: #1713 ? you can disable builders, which most likely solves your problem..

Why are you combining setter/getter with builder?

[DmitriiSolovev]

JPA requires getters/setters. The Builder annotation is convenient for testing (mock data). If I remove the Builder annotation from the SecondEntityDTO class - will this solve the problem?

[sjaakd]

If I remove the Builder annotation from the SecondEntityDTO class - will this solve the problem?

Most likely yes.. The Builder implies to us (at this point in time) immutable. Hence, we try to analyse it that way.

[sjaakd]

@DmitriiSolovev .. That this solve your problem?

[DmitriiSolovev]

@DmitriiSolovev .. That this solve your problem?

@sjaakd I need both getters/setters (jpa) and a builder (mock data, unit testing etc, ). As a workaround, I use MapStruct 1.2.0.Final now. However, it seems to me that this will help me - https://projectlombok.org/features/experimental/Accessors

@Accessors(chain = true)

Then I can remove Builder annotation. I will write you the results later.

[michalgce]

Same problem here with nested objects

    void updateDto(ChargerCrnk chargerCrnk, @MappingTarget ChargerDTO charger);

Generate

public void updateDto(ChargerCrnk chargerCrnk, ChargerDTO charger) {
        if ( chargerCrnk == null ) {
            return;
        }

        if ( charger.getMetadata() == null ) {
            charger.setMetadata( ChargerMetadataDTO.builder() );
        }
...

[ajayshenoyh]

I have the same problem when source and target is of same class. I am going with work around MapStruct 1.2.0.Final for now. Thanks! @DmitriiSolovev