Embedded entity with mixup of strings and long for the same attribute works till 2.2.X but not upon 2.3.X

[MichaBub]

Describe the bug
Having an embedded entity annotated as entity can be properly mapped / read from DB with 2.2, but not with 2.3
Attention: The documents in mongo for this error can be either contain string or long values - this worked fine with 2.2, not with 2.3

e.g. Java class:

@Entity(useDiscriminator = false)
public class MyId implements Serializable {
    private static final long serialVersionUID = -1L;
    protected long myId;
    public MyId() {
    }
    public MyId(long myId) {
        this.myId = myId;
    }
    public MyId(String myId) {
        this.myId = Long.parseLong(myId);
    }
}

and data in mongo with mixup of long and string

{
    "_id" : {
        "identifier" : "1"
    },
	"blabla" : {
        "myId" : NumberLong(123)
    }
},
{
    "_id" : {
        "identifier" : "2"
    },
	"blabla" : {
        "myId" : "1234"
    }
}

will result in:
Caused by: dev.morphia.mapping.MappingException: The type 'xxx.xxx.MyId' can not be instantiated: Can not set long field xxx.xxx.myId to java.lang.String

[evanchooly]

Can you put together a reproducer? I'm not sure how that would work under 2.2 but not 2.3, either.

[MichaBub]

Hi @evanchooly

I invested time in fixing this issue not writing the sample code with reproducer yet.
--> Loading all documents from mongo with 2.2, and deleting plus saving again every single document did the trick.

But I can tell you it works with 2.2 and the mixup of string/long/int fields in mongo with this trick (this API got removed in 2.3):

datastore.getMapper().mapExternal(null, aggregate);

see full implementation:

        MapperOptions mapperOptions = MapperOptions.builder()
                .collectionNaming(NamingStrategy.identity())
                .propertyNaming(NamingStrategy.identity())
                .build();
        datastore = Morphia.createDatastore(mongoClient, this.dbName, mapperOptions);

        Set<Class<?>> aggregates = loadAnnotatedWithEntity();
        for (Class aggregate : aggregates) {
            datastore.getMapper().map(aggregate);
            datastore.getMapper().mapExternal(null, aggregate);
            datastore.ensureIndexes(aggregate);
        }
    }

    public static Set<Class<?>> loadAnnotatedWithEntity() {
        Reflections reflections = new Reflections("com.mypackage");
        Set<Class<?>> classes = reflections.getTypesAnnotatedWith(Entity.class);
        return classes;
    }

How can you get the attribute which is type long in the entity as type string in the mongo database.
--> Via a plain json importer which loads anything as document in your db:
But anyway, the issue is about reading the entity, which works with 2.2 but not with 2.3

        MongoCollection<BasicDBObject> collection = datastore
                .getDatabase()
                .getCollection("myCollection", BasicDBObject.class);
        BasicDBObject document = BasicDBObject.parse(StreamUtilUTF8.fromInputStream(this.getClass().getClassLoader().getResourceAsStream("json/myfile.json")));
        collection.insertOne(document);

[evanchooly]

that reproducer would really help. Seeing what changes in the database would be useful to see.

[MichaBub]

Hi @evanchooly

okay I wrote reproducer tests to compare

Morphia 2.2.3 - working
https://github.com/MichaBub/reproducer/tree/works_with_morphia_2_2_3

Morphia 2.3.0 - broken
https://github.com/MichaBub/reproducer/tree/broken_with_morphia_2_3

and the diff of changes:
https://github.com/MichaBub/reproducer/pull/5/files

you´ll get the error as described with 2.3 - with 2.2.3 all works fine.

dev.morphia.mapping.MappingException: The type 'com.foo.MyId' can not be instantiated: Can not set long field com.foo.MyId.myId to java.lang.String

	at dev.morphia.mapping.internal.ConstructorCreator.getInstance(ConstructorCreator.java:118)
	at dev.morphia.mapping.codec.pojo.EntityDecoder.decode(EntityDecoder.java:43)