FAQ: Handling Optional Values in SwiftData

[skalber-mm]

I'm getting a crash with the following error:

It looks like the issue is in the currentRoomPredicate, if I remove it from the conjunction array it doesn't crash:

Is there a limit on the allowed nested objects in the predicate? I mean is the problem with contract.listing?.room?.persistentModelID ?

Thank you for the great work making this lib!

[NoahKamara]

Thank you for the report :) It might be an issue with PersistentIdentifier or NilLiteral.

Can you provide a minimal reproducible example?

[NoahKamara]

I am trying to reproduce the issue and am getting a SwiftData crash when trying to access nested relationships:

@Model
class PersonModel {
    @Relationship
    var partner: PersonModel?
}

let nestedRelationshipPredicate = #Predicate<PersonModel> { person in
    person.partner?.partner?.persistentModelID == modelID
}

try context.fetch(.init(predicate: nestedRelationshipPredicate))

This seems to be an issue with SwiftData. I suggest trying to try unwrapping the optionals:

if let listing = contract.listing { ... } else { false }

I would welcome a minimal reproducible example as I am so far unable to reproduce this specific crash

[skalber-mm]

Yes thanks, managed to solve it by reading this article: https://fatbobman.com/en/posts/how-to-handle-optional-values-in-swiftdata-predicates/

[NoahKamara]

Happy to hear you could solve the issue. I'm closing it but marking it with FAQ for others with the same problem