Description

I'm testing the pre-release branch with our existing app. We had some code creating a bunch of nested items with UUID IDs for the primary keys in a loop which now throws an error but worked in 10.20.0 and earlier.

function loadThings(importModel: ImportModel[]) {
    realm.write(() => {
        for (const item of importModel) {

            const savedRealmThing = realm.create<RealmThing>(RealmThing.schema.name, createRealmThing(item))

            const aliases = item.aliases ? item.aliases : []
            const thingNames = [...aliases, item.name]
            thingNames.forEach((name) => {
                const alias = {
                    id: uuid.v4(),
                    thing: savedRealmThing,
                    name: name,
                    schema: latestRealmSchema.realmAlias,
                }
                realm.create<RealmAlias>(RealmAlias.schema.name, alias)
            })
        }
    })
    return importModel.length
}

When it gets to realm.create<RealmAlias>(RealmAlias.schema.name, alias) it dies, apparently because it's trying to recreate the nested savedRealmThing and the object already exists. Changing that line to realm.create<RealmAlias>(RealmAlias.schema.name, alias, Realm.UpdateMode.Modified) fixes the issue.

It seems like the existing behaviour for realm.create() with no UpdateMode was Modified but is now Never, was this a deliberate change?

Stacktrace & log output

Error is: `Exception in HostFunction: Attempting to create an object of type 'RealmThing' with an existing primary key value ''0c5f1ca1-1e08-48a2-a75b-e5a302db67d5''.`

Can you reproduce a bug?

Yes, always

Reproduction Steps

See example code in description

Version

hermes (10.20.0-beta.1)

What SDK flavour are you using?

Local Database only

Are you using encryption?

No, not using encryption

Platform OS and version(s)

RN 0.66.3 using JSC (not Hermes!) - iPhone 13 Simulator w/ iOS 15.2, Android AVD Emulator running Android 9.0