Empty set fails to deserialise back into empty hashset

[Zk2u]

When a column with a Set type is inserted and defaulted (to become an empty hash set), it is stored in Scylla as null. When reading this, the crate fails to convert the null into an empty hashset.

Apologies for bad image

failed to find meals: NextRowError("SELECT chef, id, name, description, ingredients, allergens, dietary_requirements, images, added_on FROM meals WHERE chef = ?", FromRowError(BadCqlVal { err: ValIsNull, column: 7 }))

[GoranBrkuljan]

https://opensource.docs.scylladb.com/stable/cql/types.html#sets

ScyllaDB does not distinguish an empty collections from a missing value so using Option<Set<T>> is recommended.

[Zk2u]

That's so dumb, the main driver should use an empty collection for this case lol. Thank you, saved the day once again!

[GoranBrkuljan]

I agree, it's bit unexpected behavior. ~Maybe we could have some kind of compile time checks if collection is not Option and raise an error.~

[Zk2u]

Driver changes tracked upstream here.