mongoose: Cannot assign to read only property 'remove' of object '[object Array]'

I’m using MongoDB 3.6.4 Community, NodeJS 8.9.4 and Mongoose 5.0.17, on Windows 10 Professional

From time to time the following stack trace shows on console, stopping the application:

F:\Proj1\node_modules\mongoose\node_modules\mongodb\lib\utils.js:132
      throw err;
      ^

TypeError: Cannot assign to read only property 'remove' of object '[object Array]'
    at new MongooseDocumentArray (F:\Proj1\node_modules\mongoose\lib\types\documentarray.js:45:20)
    at DocumentArray.cast (F:\Proj1\node_modules\mongoose\lib\schema\documentarray.js:274:13)
    at DocumentArray.SchemaType.getDefault (F:\Proj1\node_modules\mongoose\lib\schematype.js:671:23)
    at $__applyDefaults (F:\Proj1\node_modules\mongoose\lib\document.js:298:22)
    at model.Document (F:\Proj1\node_modules\mongoose\lib\document.js:118:3)
    at model.Model (F:\Proj1\node_modules\mongoose\lib\model.js:62:12)
    at new model (F:\Proj1\node_modules\mongoose\lib\model.js:3776:13)
    at Object.createModel (F:\Proj1\node_modules\mongoose\lib\queryhelpers.js:106:10)
    at completeMany (F:\Proj1\node_modules\mongoose\lib\query.js:1467:22)
    at cb (F:\Proj1\node_modules\mongoose\lib\query.js:1328:11)
    at result (F:\Proj1\node_modules\mongoose\node_modules\mongodb\lib\utils.js:414:17)
    at executeCallback (F:\Proj1\node_modules\mongoose\node_modules\mongodb\lib\utils.js:406:9)
    at handleCallback (F:\Proj1\node_modules\mongoose\node_modules\mongodb\lib\utils.js:128:55)
    at self.close (F:\Proj1\node_modules\mongoose\node_modules\mongodb\lib\cursor.js:904:60)
    at handleCallback (F:\Proj1\node_modules\mongoose\node_modules\mongodb\lib\utils.js:128:55)
    at completeClose (F:\Proj1\node_modules\mongoose\node_modules\mongodb\lib\cursor.js:1043:14)
Waiting for the debugger to disconnect...

Is it a bug? It doesn’t trace back to any of my project files.

About this issue

Original URL
State: closed
Created 6 years ago
Comments: 15

Commits related to this issue

test(document): repro #6431 — committed to Automattic/mongoose by vkarpov15 6 years ago
fix(array): use `push()` instead of `concat()` because of array subclassing quirks in node v4 and v5 Re: #6431 — committed to Automattic/mongoose by vkarpov15 6 years ago

Most upvoted comments

express is superfluous, this can be replicated with just mongoose and lighthouse:

6431.js

#!/usr/bin/env node
'use strict';

const lighthouse = require('lighthouse')
const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/test');
const conn = mongoose.connection;
const Schema = mongoose.Schema;

const sub = new Schema({
  name: String
});

const schema = new Schema({
  arr: [sub]
});

const Test = mongoose.model('test', schema);

const test = new Test({
  arr: [{ name: 'test' }]
});

async function run() {
  await conn.dropDatabase();
  await test.save();
  return conn.close();
}

run().catch(console.error);

Outputs:

issues: ./6431.js
/Users/lineus/dev/Help/mongoose5/node_modules/mongoose/lib/types/documentarray.js:45
    arr[keysMA[j]] = MongooseArray.mixin[keysMA[j]];
                   ^

TypeError: Cannot assign to read only property 'remove' of object '[object Array]'
    at new MongooseDocumentArray (/Users/lineus/dev/Help/mongoose5/node_modules/mongoose/lib/types/documentarray.js:45:20)
    at DocumentArray.cast (/Users/lineus/dev/Help/mongoose5/node_modules/mongoose/lib/schema/documentarray.js:274:13)
    at DocumentArray.SchemaType.getDefault (/Users/lineus/dev/Help/mongoose5/node_modules/mongoose/lib/schematype.js:671:23)
    at $__applyDefaults (/Users/lineus/dev/Help/mongoose5/node_modules/mongoose/lib/document.js:298:22)
    at model.Document (/Users/lineus/dev/Help/mongoose5/node_modules/mongoose/lib/document.js:118:3)
    at model.Model (/Users/lineus/dev/Help/mongoose5/node_modules/mongoose/lib/model.js:62:12)
    at new model (/Users/lineus/dev/Help/mongoose5/node_modules/mongoose/lib/model.js:3776:13)
    at Object.<anonymous> (/Users/lineus/dev/Help/mongoose5/issues/6431.js:20:14)
    at Module._compile (module.js:652:30)
    at Object.Module._extensions..js (module.js:663:10)
    at Module.load (module.js:565:32)
    at tryModuleLoad (module.js:505:12)
    at Function.Module._load (module.js:497:3)
    at Function.Module.runMain (module.js:693:10)
    at startup (bootstrap_node.js:188:16)
    at bootstrap_node.js:609:3
issues:

lineus on May 9, 2018