undefined selector doesn't work in SQLite

[marius-se]

I'm using the Capactior SQLite adapter and noticed that a query like this:

const selector: MangoQuerySelector<ValveDocument> = {
  radiator_id: radiatorId,
  replaced_valve_id: undefined, // <--- this is the troublemaker
};

return this.db.valves
  .findOne({ selector })

doesn't return any results: It does however return the correct result when using the IndexedDB adapter. The document I'm trying to find looks exactly the same in both storages (IndexedDB and Capacitor SQLite): In both cases the replaced_valve_id key/value is not present at all.

This is the document in the IndexedDB (as you can see -> no replaced_valve_id):

This is the document in SQLite (also no replaced_valve_id):

If I remove the replaced_valve_id: undefined it'll work correctly with both storage adapters!

[pubkey]

@marius-se Can you paste your schema or send it to me privately via discord?

[pubkey]

Ok I did some investigations.

• Having $type: 'undefined' is depreacted in MongoDB: https://www.mongodb.com/docs/manual/reference/bson-types/migrate-undefined/#update-fields-with-unknown-names
• RxDB needs to send queries across realms (like to a WebWorker) and therefore will JSON.stringify() the query which will make it loose any undefined fields.

I will add a dev-mode check to ensure a query is not allowed to have undefined in it. There is no real reason to ever put this in.

To query for documents where field X does not exists, use the $exists operator or { $eq: null }.

[pubkey]

Fixed here: #6795