Automattic/mongoose · error · Error

For your own good, Mongoose does not know how to remove an A

Error message

For your own good, Mongoose does not know how to remove an ArraySubdocument that has no _id

What it means

ArraySubdocument.prototype.$__removeFromParent() (invoked by subdoc.deleteOne()) removes the element from its parent array via parentArray.pull({ _id }). If the subdocument has no _id — typically because the array's schema was declared with { _id: false } — Mongoose has no key to pull by and refuses rather than silently removing the wrong element.

Source

Thrown at lib/types/arraySubdocument.js:101

/*!
 * ignore
 */

ArraySubdocument.prototype.populate = function() {
  throw new Error('Mongoose does not support calling populate() on nested ' +
    'docs. Instead of `doc.arr[0].populate("path")`, use ' +
    '`doc.populate("arr.0.path")`');
};

/*!
 * ignore
 */

ArraySubdocument.prototype.$__removeFromParent = function() {
  const _id = this._doc._id;
  if (!_id) {
    throw new Error('For your own good, Mongoose does not know ' +
      'how to remove an ArraySubdocument that has no _id');
  }
  this.__parentArray.pull({ _id: _id });
};

/**
 * Returns the full path to this document. If optional `path` is passed, it is appended to the full path.
 *
 * @param {string} [path]
 * @param {boolean} [skipIndex] Skip adding the array index. For example `arr.foo` instead of `arr.0.foo`.
 * @return {string}
 * @api private
 * @method $__fullPath
 * @memberOf ArraySubdocument
 * @instance
 */

ArraySubdocument.prototype.$__fullPath = function(path, skipIndex) {

View on GitHub (pinned to 49cdab0136)

Solutions

1. Remove { _id: false } from the subdocument schema so elements get _ids
2. Or delete by value/index through the parent array: doc.subs.pull({ name: 'x' }) or doc.subs = doc.subs.filter(s => s !== target)
3. For data already lacking _ids, backfill _ids before using deleteOne()

Example fix

// before
const subSchema = new Schema({ name: String }, { _id: false });
// ...
doc.subs[0].deleteOne(); // throws
// after
const subSchema = new Schema({ name: String }); // default _id: true
doc.subs[0].deleteOne();

function deleteSubdoc(arr, subdoc) {
  if (subdoc._id == null) {
    arr.splice(arr.indexOf(subdoc), 1); // fallback by identity
    return;
  }
  subdoc.deleteOne();
}

function canDeleteOne(subdoc) { return subdoc._id != null; }

try { doc.subs[0].deleteOne(); } catch (err) { if (/no _id/.test(err.message)) { doc.subs = doc.subs.filter(s => s !== doc.subs[0]); } else throw err; }

When it happens

Trigger: new Schema({ subs: [new Schema({ name: String }, { _id: false })] }) followed by doc.subs[0].deleteOne(); calling deleteOne() on any array subdocument whose _id is missing.

Common situations: Disabling _id on subdocument arrays to save storage or match legacy data, then using element-level deleteOne(); loading documents from collections that never stored element _ids.

Related errors

• Aggregate.prototype.exec() no longer accepts a callback
• Expected path "${path}" to be populated
• Infinite subdocument loop: subdoc with _id ${doc._id} is a p
• Document deleteOne pre hooks cannot overwrite arguments
• Cast to embedded failed for value "${value}" (type ${valueTy

AI-assisted analysis of Automattic/mongoose@49cdab0136 (2026-08-21). Data as JSON: /api/errors/c011c876bb06336e. Report an issue: GitHub.