Nested properties of non-strict schema are undefined after reload

[adamreisnz]

Do you want to request a feature or report a bug?
Bug

What is the current behavior?
Nested properties of a non-strict schema appear as undefined after a document is loaded from the database

If the current behavior is a bug, please provide the steps to reproduce.

const mongoose = require('mongoose')
const {Schema} = mongoose
const uri = `mongodb://localhost:27017/test`

mongoose.set('debug', true)
console.log(`Mongoose version: ${mongoose.version}`)

//Schema
const NestedSchema = new Schema({}, {
  id: false,
  _id: false,
  strict: false,
})

const ItemSchema = new Schema({
  name: {
    type: String,
  },
  nested: NestedSchema,
})

//Model
const Item = mongoose.model('Item', ItemSchema)

//Run function
async function run() {
  await mongoose.connect(uri)

  //Create new item
  const item = await Item.create({
    name: 'Test',
    nested: {
      something: 1,
      else: 'test',
      foo: {
        bar: 55,
      },
    },
  })

  console.log(`After creation: ${item.nested.foo.bar}`)

  //Modify nested data
  item.nested.foo.bar = 66
  item.markModified('nested.foo.bar')
  await item.save()

  console.log(`After save: ${item.nested.foo.bar}`)

  //Reload
  const reloaded = await Item.findOne({_id: item._id})
  console.log(`After reload: ${reloaded.nested}`)
  console.log(`After reload: ${reloaded.nested.foo}`)
  console.log(`After reload: ${reloaded.nested.foo.bar}`)
}

//Run
run().catch(err => console.log(err))

What is the expected behavior?
To be able to log the nested property foo and see it's value after reloading the item from the database.
Instead, foo is undefined.

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.
Mongoose 6.1.10
MongoDB 5.0.3
Node 16.13.1

[adamreisnz]

Thanks @vkarpov15, so this was a confirmed issue?

[vkarpov15]

@adamreisnz yes this is a confirmed bug and will be fixed in v6.2.1