Mapstruct 1.4.2.Final : NullValuePropertyMappingStrategy.SET_TO_DEFAULT not working as expected

Question

I have recently updated my spring boot version from 2.3.0.RELEASE to 2.4.4 and also updated the Map Struct version to the latest from 1.3.1.Final to is 1.4.2.Final. lombok version used - 1.18.18

But one of the mapper which was working fine with 1.3.1 is not working anymore with 1.4.2 and the scenario is as below.

POM:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.4</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    ......

    <properties>
        <!-- used for configuration meta data processor, please keep in sync with 
            spring boot parent version -->
        <spring-boot.version>2.4.4</spring-boot.version>
        <java.version>11</java.version>
        <org.mapstruct.version>1.3.1.Final</org.mapstruct.version>
        .....
    </properties>

    <dependencies>
        ........
        ........
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct</artifactId>
            <version>${org.mapstruct.version}</version>
        </dependency>
        ........
        ........
    </dependencies>

    <build>
        <finalName>dras_mt</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <annotationProcessorPaths>
                        <path>
                            <groupId>org.mapstruct</groupId>
                            <artifactId>mapstruct-processor</artifactId>
                            <version>${org.mapstruct.version}</version>
                        </path>
                        <path>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                            <version>${lombok.version}</version>
                        </path>
                        <path>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok-mapstruct-binding</artifactId>
                            <version>0.2.0</version>
                        </path>
                        ........
                        ........
                    </annotationProcessorPaths>
                </configuration>
            </plugin>
            ......
            ......
        </plugins>
        <pluginManagement>
            .....
        </pluginManagement>
    </build>
</project> 

Entity:

@Entity
@Data
public class TestEntity {
    @Id
    private Long id;

    @NotNull
    private String plntId;

    @NotNull
    private Boolean approvalNeeded = false;
}

Domain:

@Value
@Builder(toBuilder = true)
public class TestDomain {
    private PlantDomain plantDomain;

    @NonFinal
    @Setter
    private SomeInfo someInfo;

    @NonFinal
    @Setter
    @Default
    private Boolean approvalNeeded = false;
}

Mapper:

@Mapper(componentModel = "spring", uses = { ActaulPlantMapper.class })
public interface TestEntityMapper {
    @Mapping(target = "someInfo", ignore = true)
    @Mapping(source = "plntId", target = "plantDomain")
    @Mapping(target = "approvalNeeded", nullValuePropertyMappingStrategy = NullValuePropertyMappingStrategy.SET_TO_DEFAULT)
    TestDomain fromEntity(TestEntity entity);    
}

Generated Code with MapStruct 1.3.1

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2021-03-24T11:33:38+0530",
    comments = "version: 1.3.1.Final, compiler: javac, environment: Java 11.0.9.1 (AdoptOpenJDK)"
)
@Component
public class TestEntityMapperImpl implements TestEntityMapper {

    @Autowired
    private ActualPlantMapper actualPlantMapper;

    @Override
    public TestDomain fromEntity(WareHouseOptionEntity entity) {
        if ( entity == null ) {
            return null;
        }    
        TestDomainBuilder testDomain = TestDomain.builder();
        testDomain.plantDomain( actualPlantMapper.fromSapId( entity.getPlntId() ) );
        if ( entity.getApprovalNeeded() != null ) {
            testDomain.approvalNeeded( entity.getApprovalNeeded() );
        }
        else {
            testDomain.approvalNeeded( false );
        }    
        return testDomain.build();
    }
}

Generated Code with MapStruct 1.4.2

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2021-03-24T11:33:38+0530",
    comments = "version: 1.3.1.Final, compiler: javac, environment: Java 11.0.9.1 (AdoptOpenJDK)"
)
@Component
public class TestEntityMapperImpl implements TestEntityMapper {

    @Autowired
    private ActualPlantMapper actualPlantMapper;

    @Override
    public TestDomain fromEntity(WareHouseOptionEntity entity) {
        if ( entity == null ) {
            return null;
        }    
        TestDomainBuilder testDomain = TestDomain.builder();
        testDomain.plantDomain( actualPlantMapper.fromSapId( entity.getPlntId() ) );            
        testDomain.approvalNeeded( entity.getApprovalNeeded() );               
        return testDomain.build();
    }
}

As you see with 1.4.2 version the NullValuePropertyMappingStrategy.SET_TO_DEFAULT is not applied.

I have tried with other options like putting the NullValuePropertyMappingStrategy on class level which didn't help.

Any futher inputs is highly appreaciated.

Answer 1

The fact that NullValuePropertyMappingStrategy was working on 1.3 is a coincidence. The strategy should only be applicable to update methods i.e. methods with @MappingTarget.

If you want to keep defaults as defined in your source class I would suggest using NullValueCheckStrategy#ALWAYS