Assistance Needed: Handling Mixed _id Types (String and ObjectId) in Quarkus with MongoDB Panache

[nitinty]

Hi Team,

We are facing an issue with mapping the _id field in our existing MongoDB collections. Our collections already exist, and several of them have a mix of String and ObjectId values for the _id field.

In our previous setup with Spring, we handled this using:

@Id  
private String id;  

This approach worked seamlessly.

However, when attempting the equivalent in Quarkus:

@BsonId  
@BsonProperty("_id")  
private String id;  

We encounter the following error:

Failed to decode 'TestEntity'. Decoding 'id' errored with: readString can only be called when CurrentBSONType is STRING, not when CurrentBSONType is OBJECT_ID.

Could you please suggest a workaround or best practice to handle this scenario in Quarkus?

Thanks in advance for your guidance!

[quarkus-bot[bot]]

/cc @FroMage (panache), @loicmathieu (mongodb,panache)

[xstefank]

I talked to @nitinty offline about this first, but since I wasn't sure if this is intended behavior or not, I delegated to opening an issue.

If someone wants a reproducer, here it is - https://github.com/xstefank/quarkus-reproducers/tree/main/mongo-id.

[loicmathieu]

Hi,

This should be the correct implementation in case you want a custom ID field that is a String:

@BsonId    
private String id;  

However, it seems you field is sometimes a String and sometimes an ObjectId, I'm afraid it cannot work OOTB as we use the PojoCode wich only do 1 <-> 1 mapping of BSON type to Java type.
The only thing I can think off would be a custom code for your field.

[nitinty]

I tried this with fresh collection/entity but it didn't worked and through similar kind of error

Failed to decode 'PersonEntity'. Decoding 'id' errored with: readString can only be called when CurrentBSONType is STRING, not when CurrentBSONType is OBJECT_ID.

@MongoEntity(collection = "persons")
@Data
public class PersonEntity extends BaseAuditer {
    @BsonId
    private String id;
   
    private String name;
   
    private int age;
}


public interface PersonRepository extends PanacheMongoRepositoryBase<PersonEntity, String> {
    void savePeople(PersonEntity person) ;
    List<PersonEntity> findAll();
}


@ApplicationScoped
public class PersonRepositoryImpl implements PersonRepository {

    @Override
    public void save(PersonEntity person) {
        persist(person);
    }

    @Override
    public List<PersonEntity> findAll() {
        return listAll();
    }
}


********* Test Case ********

    @Test
    public void testMongoDatabaseResolverUsingPersonResource() {
        PersonEntity person = new PersonEntity();
        person.setAge(34);
        person.setName("Person");
        personRepository.save(person); 
        /* 
         Above code stored the below document in the mongoDB
          {
            _id: ObjectId('677f9200d532e830782d6195'),
            age: 34,
            name: 'Person'
          }
         */
        
        personRepository.findAll();  // Getting error on this line 

    }

[xstefank]

@loicmathieu They have ObjectId in Mongo, and they want to pull ID as a String. So the question is if we should be doing ObjectId -> String mapping in the background. I personally also don't think that this is aligned with relational mapping in hibernate and it might be confusing if it differs for mongo. But this is your decision.