(fix): Throws error when updating a key name that match the discriminator key name on nested object

[lpizzinidev]

closes #12517

[hasezoey]

LGTM, though i dont know much about the internals of discriminators

[abarriel]

Can a discriminator be set deeper and not only on root? if it's the case we should handle that
discriminatorKey: 'obj.objkind',

[lpizzinidev]

Can a discriminator be set deeper and not only on root?

@abarriel This is the question.
I've been conservative and assumed that the discriminator may be set only on root properties.
The other approach, as you pointed out, would be to allow deeper discriminators, something like discriminatorKey: 'obj.objkind'.

I'll wait for more feedback and apply changes if needed.

[vkarpov15]

Let's make this (prefix ? prefix + '.' + key : key) === schema.options.discriminatorKey &&

Although we don't have test coverage for nested discriminator keys, it seems to work at first glance. For example, the following script works as expected.

'use strict';

const mongoose = require('mongoose');
mongoose.set('debug', true);

const { Schema } = mongoose;

run().catch(err => console.err(err));

async function run() {
  await mongoose.connect('mongodb://localhost:27017/test');

  const schema = new Schema({ name: String, meta: { test: String } }, { discriminatorKey: 'meta.kind' });
  const Test = mongoose.model('Test', schema);
  const Disc = Test.discriminator('Disc', Schema({ test: String }));

  const disc = new Disc({ name: 'test' });
  await disc.save();

  console.log(await Disc.findById(disc));
}

Given that, it would be great if this check didn't break on if discriminator key has a ..

[lpizzinidev]

👍 I'll work on this

[vkarpov15]

Thanks 👍