SwiftData crashes when fetching certain types of enum cases

Originator:darren.mo
Number:rdar://FB13408892 Date Originated:2023-11-24
Status:Closed Resolved:iOS 18
Product:SwiftData Product Version:iOS 17.2 Seed 3 (21C5046c)
Classification:Incorrect/Unexpected Behavior Reproducible:Always
 
I have a model class that has a persistent property for a `Codable` enum. If the enum type is written a certain way, the app will crash because SwiftData encounters the following fatal error: `Could not cast value of type 'Swift.Optional<Any>' (0x1f5b7ff50) to 'SwiftDataCodableEnumCrash.Item.NestedEnum' (0x102a14cd0)`. The full stack trace is attached.

I have attached a minimal sample project reproducing the issue. `Item.swift` is annotated with comments explaining the significance of certain pieces of code. Below is a summary of the conditions that are needed to trigger the SwiftData bug:
- There needs to be a nested enum.
- Within the nested enum, there needs to be a case without an associated value.

Comments

Apple

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iOS 18 beta (Build: 22A5282m) https://developer.apple.com/download/

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