Automattic/mongoose · error · Error

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

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.

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
• Can't use
• Cannot create use schema for property
• Cannot set default value of path
• Cast to embedded failed for value

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

Appendix: 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) {

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