different behavior for key starting with dot ('.')

[rohanricky]

Prerequisites

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

Mongoose version

6.12.3

Node.js version

18.12.1

MongoDB server version

4.4

Typescript version (if applicable)

No response

Description

var mongoose = require('mongoose')
console.log(mongoose.version)
let Schema = mongoose.Schema
var eventSchema = new Schema({
  name: { type: String },
  field3: { type: Schema.Types.Mixed },
  __stateBeforeSuspension: {
    field1: { type: String },
    field2: { type: String },
    field3: { type: Schema.Types.Mixed },
    jsonField: {
        name: { type: String },
        ex: { type: String }
    }
  }
})

eventSchema.add({
  test: { 
    val1: { type: String },
    val2: { type: String }
   }
})

eventSchema.add({
  subSchema4: [{ field1: { type: String } }, { field2: { type: String } }]
})

var Event = mongoose.model('Event', eventSchema)
async function run() {
  await mongoose.connect('mongodb://localhost:27017');
  let eventObj = new Event({ name: 'event object', __stateBeforeSuspension: { field1: 'test', jsonField: { name: null, ex: 'test' }}, test: { val1: 'hello', val2: 'there' }, subSchema4: [{ field1: 'test' }, { field2: 'test2' }] })
  eventObj.save(function (err, eventObj) {
    const newO = eventObj.toObject()
    newO.__stateBeforeSuspension.field3 = {'.ippo': 5}
    eventObj.set(newO)
    eventObj.save(function (err, eventObj) {
      console.log(eventObj)
    })
  })
}
run();

Output with 6.12.3

{
  name: 'event object',
  __stateBeforeSuspension: {
    field1: 'test',
    field3: { '': [Object] },
    jsonField: { name: null, ex: 'test' }
  },
  _id: new ObjectId("657ae93de1d6bf5012d5e889"),
  test: { val1: 'hello', val2: 'there' },
  subSchema4: [
    { field1: 'test', _id: new ObjectId("657ae93de1d6bf5012d5e88a") },
    { _id: new ObjectId("657ae93de1d6bf5012d5e88b") }
  ],
  __v: 0
}

Output with 5.12.5

{
  __stateBeforeSuspension: {
    jsonField: { name: null, ex: 'test' },
    field1: 'test',
    field3: { '.ippo': 5 }
  },
  _id: 657ae987986e7d5f9d5943e5,
  name: 'event object',
  test: { val1: 'hello', val2: 'there' },
  subSchema4: [
    { _id: 657ae987986e7d5f9d5943e6, field1: 'test' },
    { _id: 657ae987986e7d5f9d5943e7 }
  ],
  __v: 0
}

Steps to Reproduce

__stateBeforeSuspension.field3 in 5.12.5 : { '.ippo': 5 }
__stateBeforeSuspension.field3 in 6.12.3 : { '': [Object] } ( the [Object] is {'ippo': 5}, key is empty )

Expected Behavior

Expecting 5.12.5 behavior will be supported

[IslandRhythms]

var mongoose = require('mongoose')
console.log(mongoose.version)
const Schema = mongoose.Schema
const eventSchema = new Schema({
  name: { type: String },
  field3: { type: Schema.Types.Mixed },
  __stateBeforeSuspension: {
    field1: { type: String },
    field2: { type: String },
    field3: { type: Schema.Types.Mixed },
    jsonField: {
        name: { type: String },
        ex: { type: String }
    }
  }
})

eventSchema.add({
  test: { 
    val1: { type: String },
    val2: { type: String }
   }
})

eventSchema.add({
  subSchema4: [{ field1: { type: String } }, { field2: { type: String } }]
})

const Event = mongoose.model('Event', eventSchema)
async function run() {
  await mongoose.connect('mongodb://localhost:27017/gh14178');
  await mongoose.connection.dropDatabase();
  let eventObj = new Event({ name: 'event object', __stateBeforeSuspension: { field1: 'test', jsonField: { name: null, ex: 'test' }}, test: { val1: 'hello', val2: 'there' }, subSchema4: [{ field1: 'test' }, { field2: 'test2' }] })
  eventObj.save(function (err, eventObj) {
    const newO = eventObj.toObject()
    newO.__stateBeforeSuspension.field3 = {'.ippo': 5}
    eventObj.set(newO)
    eventObj.save(function (err, eventObj) {
      console.log(eventObj)
    })
  })
}
run();

[sakethyerra]

@vkarpov15 @IslandRhythms, Can you please let us know if there is any tentative time line to release this one.

[vkarpov15]

@sakethyerra we'll ship 6.12.5 with the fix next week