Entity's list has the same objects multiple times

Describe the bug I have a class marked with @Entity, and it has a list, that has 3 other elements, containing different data. Example data structure:

{
  "_id": "trio",
  "_t": "SaveData",
  "position": [0.2, 1.0, 2.2],
  "elements": [
    {
      "_t": "ChildData",
      "position": [4.0, -1.0, 2.2]
    },
    {
      "_t": "ChildData",
      "position": [2.0, -1.0, 4.0]
    },
    {
      "_t": "ChildData",
      "position": [-3.5, 0.0, 3.5]
    }
  ]
}

Java entity code:

@Entity("saved_stuff")
public class SaveData {
    @Id
    public final String saveName;
    public final double[] position;
    public final List<ChildData> elements;

    public SaveData(String saveName, double[] position, List<ChildData> elements) {
        this.saveName = saveName;
        this.position = position;
        this.elements = elements;
    }
    @Entity
    public static class ChildData {
        public final double[] child_position;
        public final List<ChildData> child_elements;

        public ChildData(double[] child_position, List<ChildData> child_elements) {
            this.child_position = child_position;
            this.child_elements = child_elements;
        }
    }
}

After using datastore.save(saveData), the object appears in the MongoDB database correctly (using Studio3T I have checked, the data contains the corrent values). After querying the object, the elements list contains the same ChildData object 3 times, instead of 3 separate objects containing different values. This is incorrect.

To Reproduce I do the following to query the object:

Datastore datastore = ...;
SaveData data = datastore.find(SaveData.class).filter(Filters.eq("_id", "trio")).first();

Using a debugger, i can determine that in the stored data, the elements list contains the same object 3 times.

Expected behavior I expected the elements list to contain the 3 elements that i have saved previously.

Please complete the following information:

• Server Version: 5.0.8
• Driver Version: 4.2.2
• Morphia Version: 2.2.6

[evanchooly]

@MrGazdag I’ve confirmed the issue on 2.2.6 and that the fix is in 2.2.7. My last comment was for @WeeHorse and not on your issue specifically. I’ve been waiting feedback on one particular issue to confirm a fix there but I’ll just push 2.2.7 to get you the fixes you need and address the other with a later release if necessary.

[evanchooly]

I just pushed 2.2.7. It should be on central as soon as the sync finishes. Give it an hour or two and you should be set.