Default value not work properly

[JohnGreaves]

While I use mapstruct, I found the bug:

For example:

@Mapper(componentModel = "spring")
public interface ExceptionMapper {
@Mappings({
            @Mapping(source = "error", target = "internalErrorMessage", qualifiedByName = "formInternalMessage"),
            @Mapping(source = "error", target = "additionalParams", qualifiedByName = "formAdditionalParams"),
            @Mapping(source = "error", target = "internalCode", qualifiedByName = "formInternalCode"),
            @Mapping(source = "httpCode", target = "httpCode", defaultValue = "400"),
    })
    MkwExceptionDto objectErrorToDto(ObjectError error, Integer httpCode);

and Mapstruct generates:

if ( httpCode != null ) {
            if ( httpCode != null ) {
                mkwExceptionDto.setHttpCode( httpCode );
            }
            else {
                mkwExceptionDto.setHttpCode( 400 );
            }
        }

Depends on double-checking on null, the default value never be set.

<org.mapstruct.version>1.3.1.Final</org.mapstruct.version>

[chris922]

Thanks for reporting this issue, I did a quick test and indeed.. this looks like a bug

Reproduciable via:

@Mapper
public interface TestMapper {
    @Mapping(target = "httpCode", source = "httpCode", defaultValue = "400")
    MkwExceptionDto objectErrorToDto(Object source, Integer httpCode);

    class MkwExceptionDto {
        Integer httpCode;

        public Integer getHttpCode() {
            return httpCode;
        }

        public void setHttpCode(Integer httpCode) {
            this.httpCode = httpCode;
        }
    }
}

Generated code with 1.3.1.Final:

public class TestMapperImpl implements TestMapper {

    @Override
    public MkwExceptionDto objectErrorToDto(Object source, Integer httpCode) {
        if ( source == null && httpCode == null ) {
            return null;
        }

        MkwExceptionDto mkwExceptionDto = new MkwExceptionDto();

        if ( httpCode != null ) {
            if ( httpCode != null ) {
                mkwExceptionDto.setHttpCode( httpCode );
            }
            else {
                mkwExceptionDto.setHttpCode( 400 );
            }
        }

        return mkwExceptionDto;
    }
}

[filiphr]

Closing this as a duplicate of #2023. That one uses defaultExpression, but the gist of it is the same. Let me know if you don't agree.

You can workaround this by wrapping the httpCode in an object. For example:

public class HttpCode {

    private final int value;

    private HttpCode(int value) {
        this.value = value;
    }

    public int getValue() {
        return value;
    }

    public static HttpCode create(Integer httpCode, int defaultHttpCode) {
        return httpCode != null ? new HttpCode(httpCode) : new HttpCode(defaultHttpCode);
    }
}

And then your mapper will look like:

@Mapper
public interface TestMapper {
    @Mapping(target = "httpCode", source = "httpCode.value", defaultValue = "400")
    MkwExceptionDto objectErrorToDto(Object source, HttpCode httpCode);
}