Hi there, I got two models here:
Two Models, with Many-To-Many Relationship
@Model
final class PresetParams: Identifiable {
@Attribute(.unique) var id: UUID = UUID()
var positionX: Float = 0.0
var positionY: Float = 0.0
var positionZ: Float = 0.0
var volume: Float = 1.0
@Relationship(deleteRule: .nullify, inverse: \Preset.presetAudioParams)
var preset = [Preset]()
init(position: SIMD3<Float>, volume: Float) {
self.positionX = position.x
self.positionY = position.y
self.positionZ = position.z
self.volume = volume
self.preset = []
}
var position: SIMD3<Float> {
get {
return SIMD3<Float>(x: positionX, y: positionY, z: positionZ)
}
set {
positionX = newValue.x
positionY = newValue.y
positionZ = newValue.z
}
}
}
@Model
final class Preset: Identifiable {
@Attribute(.unique) var id: UUID = UUID()
var presetName: String
var presetDesc: String?
var presetAudioParams = [PresetParams]() // Many-To-Many Relationship.
init(presetName: String, presetDesc: String? = nil) {
self.presetName = presetName
self.presetDesc = presetDesc
self.presetAudioParams = []
}
}
To be honest, I don't fully understand how the @Relationship thing works properly in a Many-To-Many relationship situation. Some tutorials suggest that it's required on the "One" side of an One-To-Many Relationship, while the "Many" side doesn't need it.
And then there is an ObservableObject called "ModelActors" to manage all ModelActors, ModelContainer, etc.
ModelActors, ModelContainer...
class ModelActors: ObservableObject {
static let shared: ModelActors = ModelActors()
let sharedModelContainer: ModelContainer
private init() {
var schema = Schema([
// ...
Preset.self,
PresetParams.self,
// ...
])
do {
sharedModelContainer = try ModelContainer(for: schema, migrationPlan: MigrationPlan.self)
} catch {
fatalError("Could not create ModelContainer: \(error.localizedDescription)")
}
}
}
And there is a migrationPlan:
MigrationPlan
// MARK: V102
// typealias ...
// MARK: V101
typealias Preset = AppSchemaV101.Preset
typealias PresetParams = AppSchemaV101.PresetParams
// MARK: V100
// typealias ...
enum MigrationPlan: SchemaMigrationPlan {
static var schemas: [VersionedSchema.Type] {
[
AppSchemaV100.self,
AppSchemaV101.self,
AppSchemaV102.self,
]
}
static var stages: [MigrationStage] {
[AppMigrateV100toV101, AppMigrateV101toV102]
}
static let AppMigrateV100toV101 = MigrationStage.lightweight(fromVersion: AppSchemaV100.self, toVersion: AppSchemaV101.self)
static let AppMigrateV101toV102 = MigrationStage.lightweight(fromVersion: AppSchemaV101.self, toVersion: AppSchemaV102.self)
}
// MARK: Here is the AppSchemaV101
enum AppSchemaV101: VersionedSchema {
static var versionIdentifier: Schema.Version = Schema.Version(1, 0, 1)
static var models: [any PersistentModel.Type] {
return [ // ...
Preset.self,
PresetParams.self
]
}
}
Fails on iOS 18.3.x: "Failed to fulfill link PendingRelationshipLink"
So I expected the SwiftData subsystem to work correctly with version control. A good news is that on iOS 18.1 it does work. But it fails on iOS 18.3.x with a fatal Error:
"SwiftData/SchemaCoreData.swift:581: Fatal error: Failed to fulfill link PendingRelationshipLink(relationshipDescription: (<NSRelationshipDescription: 0x30377fe80>), name preset, isOptional 0, isTransient 0, entity PresetParams, renamingIdentifier preset, validation predicates (), warnings (), versionHashModifier (null)userInfo {}, destination entity Preset, inverseRelationship (null), minCount 0, maxCount 0, isOrdered 0, deleteRule 1, destinationEntityName: "Preset", inverseRelationshipName: Optional("presetAudioParams")), couldn't find inverse relationship 'Preset.presetAudioParams' in model"
Fails on iOS 17.5: Another Error
I tested it on iOS 17.5 and found another issue: Accessing or mutating the "PresetAudioParams" property causes the SwiftData Macro Codes to crash, affecting both Getter and Setter. It fails with an error:
"EXC_BREAKPOINT (code=1, subcode=0x1cc1698ec)"
Tweaking the @Relationship marker and ModelContainer settings didn't fix the problem.
