Minimize does sometimes not working. Empty object is saved.

[m0rtalis]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Mongoose version

7.4.4

Node.js version

16.20.2

MongoDB server version

7.0.0

Typescript version (if applicable)

No response

Description

Empty objects are sometimes deleted, sometimes not.

Steps to Reproduce

  mongoose.connect("mongodb://127.0.0.1:27017/test");
  const schema = new Schema({
    metadata: {
      type: {},
      default: {},
      required: true,
      _id: false
    }
  }, { minimize: true });
  const Model = model("Schema", schema);
  const m = new Model({ metadata: {} });
  await m.save();
  console.log("Document has no metadata property")

  const x = await Model.findById(m._id).exec();
  x.metadata = {};
  await x.save();
  console.log(x.$isEmpty('metadata')) // true
  console.log("Document now has empty metadata property");

Expected Behavior

The saved document has the form

{
  "_id": {
    "$oid": "64e87a78972e351e7096f778"
  },
  "__v": 0
}

but it is

{
  "_id": {
    "$oid": "64e87a78972e351e7096f773"
  },
  "__v": 0,
  "metadata": {}
}

[IslandRhythms]

Checked in compass and an empty object is there

const mongoose = require('mongoose');


async function run() {
  await mongoose.connect('mongodb://localhost:27017/gh13782');
  await mongoose.connection.dropDatabase();

  const schema = new mongoose.Schema({
    metadata: {
      type: {},
      default: {},
      required: true,
      _id: false
    }
  }, { minimize: true });
  const Model = mongoose.model("Schema", schema);
  const m = new Model({ metadata: {} });
  await m.save();
  console.log("Document has no metadata property")

  const x = await Model.findById(m._id).exec();
  x.metadata = {};
  await x.save();
  console.log(x.$isEmpty('metadata')) // true
  console.log("Document now has empty metadata property");
  console.log('what is x', x);
}

run();