Improve handling in LiveObject and ObjectSnapshot when objects are deleted

CoreStoreDemo/CoreStoreDemo/List and Object Observers Demo/Palette.swift

@@ -75,24 +75,6 @@ extension Palette {
     }
 }
 
-extension LiveObject where ObjectType == Palette {
-
-    var color: UIColor {
-
-        return UIColor(
-            hue: CGFloat(self.hue) / 360.0,
-            saturation: CGFloat(self.saturation),
-            brightness: CGFloat(self.brightness),
-            alpha: 1.0
-        )
-    }
-
-    var colorText: String {
-
-        return "H: \(self.hue)˚, S: \(round(self.saturation * 100.0))%, B: \(round(self.brightness * 100.0))%"
-    }
-}
-
 extension Palette {
 
     func setInitialValues(in transaction: BaseDataTransaction) {

CoreStoreDemo/CoreStoreDemo/SwiftUI Demo/SwiftUIView.swift

@@ -116,10 +116,10 @@ struct ColorCell: View {
 
     var body: some View {
         HStack {
-            Color(palette.color)
+            Color(palette.color ?? UIColor.clear)
                 .cornerRadius(5)
                 .frame(width: 30, height: 30, alignment: .leading)
-            Text(palette.colorText)
+            Text(palette.colorText ?? "<Deleted>")
         }
     }
 }
@@ -140,18 +140,18 @@ struct DetailView: View {
     init(palette: LiveObject<Palette>) {
 
         self.palette = palette
-        self.hue = Float(palette.hue)
-        self.saturation = palette.saturation
-        self.brightness = palette.brightness
+        self.hue = Float(palette.hue ?? 0)
+        self.saturation = palette.saturation ?? 0
+        self.brightness = palette.brightness ?? 0
     }
 
     var body: some View {
         ZStack {
-            Color(palette.color)
+            Color(palette.color ?? UIColor.clear)
                 .cornerRadius(20)
                 .padding(20)
             VStack {
-                Text(palette.colorText)
+                Text(palette.colorText ?? "<Deleted>")
                     .navigationBarTitle(Text("Color"))
                 Slider(value: $hue, in: 0.0 ... 359.0 as ClosedRange<Float>)
                 Slider(value: $saturation, in: 0.0 ... 1.0 as ClosedRange<Float>)

CoreStoreTests/DynamicModelTests.swift

@@ -292,22 +292,32 @@ class DynamicModelTests: BaseTestDataTestCase {
                     XCTAssertEqual(person.name.value, "John")
                     XCTAssertEqual(person.displayName.value, "Mr. John") // Custom getter
                     
-                    let personSnapshot1 = person.asSnapshot(in: transaction)
-                    XCTAssertEqual(person.name.value, personSnapshot1?.name)
-                    XCTAssertEqual(person.title.value, personSnapshot1?.title)
-                    XCTAssertEqual(person.displayName.value, personSnapshot1?.displayName)
+                    let personSnapshot1 = person.asSnapshot(in: transaction)!
+                    XCTAssertEqual(person.name.value, personSnapshot1.name)
+                    XCTAssertEqual(person.title.value, personSnapshot1.title)
+                    XCTAssertEqual(person.displayName.value, personSnapshot1.displayName)
                     
                     person.title .= "Sir"
                     XCTAssertEqual(person.displayName.value, "Sir John")
                     
-                    XCTAssertEqual(personSnapshot1?.name, "John")
-                    XCTAssertEqual(personSnapshot1?.title, "Mr.")
-                    XCTAssertEqual(personSnapshot1?.displayName, "Mr. John")
+                    XCTAssertEqual(personSnapshot1.name, "John")
+                    XCTAssertEqual(personSnapshot1.title, "Mr.")
+                    XCTAssertEqual(personSnapshot1.displayName, "Mr. John")
                     
-                    let personSnapshot2 = person.asSnapshot(in: transaction)
-                    XCTAssertEqual(person.name.value, personSnapshot2?.name)
-                    XCTAssertEqual(person.title.value, personSnapshot2?.title)
-                    XCTAssertEqual(person.displayName.value, personSnapshot2?.displayName)
+                    let personSnapshot2 = person.asSnapshot(in: transaction)!
+                    XCTAssertEqual(person.name.value, personSnapshot2.name)
+                    XCTAssertEqual(person.title.value, personSnapshot2.title)
+                    XCTAssertEqual(person.displayName.value, personSnapshot2.displayName)
+
+                    var personSnapshot3 = personSnapshot2
+                    personSnapshot3.name = "James"
+                    XCTAssertEqual(personSnapshot1.name, "John")
+                    XCTAssertEqual(personSnapshot1.displayName, "Mr. John")
+                    XCTAssertEqual(personSnapshot2.name, "John")
+                    XCTAssertEqual(personSnapshot2.displayName, "Sir John")
+                    XCTAssertEqual(personSnapshot3.name, "James")
+                    XCTAssertEqual(personSnapshot3.displayName, "Sir John")
+
                     
                     person.pets.value.insert(dog)
                     XCTAssertEqual(person.pets.count, 1)

Sources/DynamicObject.swift

@@ -46,7 +46,7 @@ public protocol DynamicObject: AnyObject {
     /**
      Used internally by CoreStore. Do not call directly.
      */
-    static func cs_snapshotDictionary(id: ObjectID, context: NSManagedObjectContext) -> [String: Any]
+    static func cs_snapshotDictionary(id: ObjectID, context: NSManagedObjectContext) -> [String: Any]?
     
     /**
      Used internally by CoreStore. Do not call directly.
@@ -97,11 +97,19 @@ extension NSManagedObject: DynamicObject {
         return object
     }
 
-    public class func cs_snapshotDictionary(id: ObjectID, context: NSManagedObjectContext) -> [String: Any] {
+    public class func cs_snapshotDictionary(id: ObjectID, context: NSManagedObjectContext) -> [String: Any]? {
 
-        let object = context.fetchExisting(id)! as Self
+        guard let object = context.fetchExisting(id) as NSManagedObject? else {
+
+            return nil
+        }
         let rawObject = object.cs_toRaw()
-        return rawObject.dictionaryWithValues(forKeys: rawObject.entity.properties.map({ $0.name }))
+        var dictionary = rawObject.dictionaryWithValues(forKeys: Array(rawObject.entity.attributesByName.keys))
+        for case (let key, let target as NSManagedObject) in rawObject.dictionaryWithValues(forKeys: Array(rawObject.entity.relationshipsByName.keys)) {
+
+            dictionary[key] = target.objectID
+        }
+        return dictionary
     }
     
     public class func cs_fromRaw(object: NSManagedObject) -> Self {
@@ -143,7 +151,7 @@ extension CoreStoreObject {
         return self.cs_fromRaw(object: object)
     }
 
-    public class func cs_snapshotDictionary(id: ObjectID, context: NSManagedObjectContext) -> [String: Any] {
+    public class func cs_snapshotDictionary(id: ObjectID, context: NSManagedObjectContext) -> [String: Any]? {
 
         func initializeAttributes(mirror: Mirror, object: Self, into attributes: inout [KeyPathString: Any]) {
 
@@ -170,11 +178,14 @@ extension CoreStoreObject {
                 }
             }
         }
-        let object = context.fetchExisting(id)! as Self
+        guard let object = context.fetchExisting(id) as CoreStoreObject? else {
+
+            return nil
+        }
         var values: [KeyPathString: Any] = [:]
         initializeAttributes(
             mirror: Mirror(reflecting: object),
-            object: object,
+            object: object as! Self,
             into: &values
         )
         return values

Sources/LiveObject.swift

@@ -46,10 +46,12 @@ public final class LiveObject<O: DynamicObject>: ObjectRepresentation, Hashable
     public typealias SectionID = String
     public typealias ItemID = O.ObjectID
 
-    public var snapshot: SnapshotType {
+    public var snapshot: ObjectSnapshot<O>? {
 
         return self.lazySnapshot
     }
+
+    public lazy var object: O? = self.context.fetchExisting(self.id)
     
     public func addObserver<T: AnyObject>(_ observer: T, _ callback: @escaping (LiveObject<O>) -> Void) {
         
@@ -79,7 +81,7 @@ public final class LiveObject<O: DynamicObject>: ObjectRepresentation, Hashable
         return self.id
     }
     
-    public func asLiveObject(in dataStack: DataStack) -> LiveObject<O>? {
+    public func asLiveObject(in dataStack: DataStack) -> LiveObject<O> {
         
         let context = dataStack.unsafeContext()
         if self.context == context {
@@ -106,7 +108,7 @@ public final class LiveObject<O: DynamicObject>: ObjectRepresentation, Hashable
             
             return self.lazySnapshot
         }
-        return .init(objectID: self.id, context: context)
+        return ObjectSnapshot<O>(objectID: self.id, context: context)
     }
     
     public func asSnapshot(in transaction: BaseDataTransaction) -> ObjectSnapshot<O>? {
@@ -116,7 +118,7 @@ public final class LiveObject<O: DynamicObject>: ObjectRepresentation, Hashable
             
             return self.lazySnapshot
         }
-        return .init(objectID: self.id, context: context)
+        return ObjectSnapshot<O>(objectID: self.id, context: context)
     }
 
 
@@ -159,7 +161,7 @@ public final class LiveObject<O: DynamicObject>: ObjectRepresentation, Hashable
 
     fileprivate let rawObjectWillChange: Any?
 
-    fileprivate init(objectID: O.ObjectID, context: NSManagedObjectContext, initializer: @escaping (NSManagedObjectID, NSManagedObjectContext) -> ObjectSnapshot<O>) {
+    fileprivate init(objectID: O.ObjectID, context: NSManagedObjectContext, initializer: @escaping (NSManagedObjectID, NSManagedObjectContext) -> ObjectSnapshot<O>?) {
 
         self.id = objectID
         self.context = context
@@ -179,24 +181,31 @@ public final class LiveObject<O: DynamicObject>: ObjectRepresentation, Hashable
         }
         self.$lazySnapshot.initialize({ initializer(objectID, context) })
         
-        context.objectsDidChangeObserver(for: self).addObserver(self) { [weak self] (objectIDs) in
+        context.objectsDidChangeObserver(for: self).addObserver(self) { [weak self] (updatedIDs, deletedIDs) in
 
             guard let self = self else {
 
                 return
             }
-            self.willChange()
-            self.$lazySnapshot.reset({ initializer(objectID, context) })
-            self.notifyObservers()
-            self.didChange()
+            if deletedIDs.contains(objectID) {
+
+                self.object = nil
+
+                self.willChange()
+                self.$lazySnapshot.reset({ nil })
+                self.notifyObservers()
+                self.didChange()
+            }
+            else if updatedIDs.contains(objectID) {
+
+                self.willChange()
+                self.$lazySnapshot.reset({ initializer(objectID, context) })
+                self.notifyObservers()
+                self.didChange()
+            }
         }
     }
 
-    fileprivate var object: O {
-
-        return self.context.fetchExisting(self.id)!
-    }
-
 
     // MARK: Private
     
@@ -204,7 +213,7 @@ public final class LiveObject<O: DynamicObject>: ObjectRepresentation, Hashable
     private let context: NSManagedObjectContext
 
     @Internals.LazyNonmutating(uninitialized: ())
-    private var lazySnapshot: ObjectSnapshot<O>
+    private var lazySnapshot: ObjectSnapshot<O>?
     
     private lazy var observers: NSMapTable<AnyObject, Internals.Closure<LiveObject<O>, Void>> = .weakToStrongObjects()
 
@@ -302,9 +311,9 @@ extension LiveObject where O: CoreStoreObject {
     /**
      Returns the value for the property identified by a given key.
      */
-    public subscript<V>(dynamicMember member: KeyPath<O, ValueContainer<O>.Required<V>>) -> V {
+    public subscript<V>(dynamicMember member: KeyPath<O, ValueContainer<O>.Required<V>>) -> V? {
 
-        return self.snapshot[dynamicMember: member]
+        return self.object?[keyPath: member].value
     }
 
     /**
@@ -312,15 +321,15 @@ extension LiveObject where O: CoreStoreObject {
      */
     public subscript<V>(dynamicMember member: KeyPath<O, ValueContainer<O>.Optional<V>>) -> V? {
 
-        return self.snapshot[dynamicMember: member]
+        return self.object?[keyPath: member].value
     }
 
     /**
      Returns the value for the property identified by a given key.
      */
-    public subscript<V>(dynamicMember member: KeyPath<O, TransformableContainer<O>.Required<V>>) -> V {
+    public subscript<V>(dynamicMember member: KeyPath<O, TransformableContainer<O>.Required<V>>) -> V? {
 
-        return self.snapshot[dynamicMember: member]
+        return self.object?[keyPath: member].value
     }
 
     /**
@@ -328,7 +337,7 @@ extension LiveObject where O: CoreStoreObject {
      */
     public subscript<V>(dynamicMember member: KeyPath<O, TransformableContainer<O>.Optional<V>>) -> V? {
 
-        return self.snapshot[dynamicMember: member]
+        return self.object?[keyPath: member].value
     }
 
     /**
@@ -336,22 +345,30 @@ extension LiveObject where O: CoreStoreObject {
      */
     public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToOne<D>>) -> D? {
 
-        return self.snapshot[dynamicMember: member]
+        return self.object?[keyPath: member].value
     }
 
     /**
      Returns the value for the property identified by a given key.
      */
-    public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToManyOrdered<D>>) -> [D] {
+    public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToManyOrdered<D>>) -> [D]? {
 
-        return self.snapshot[dynamicMember: member]
+        return self.object?[keyPath: member].value
     }
 
     /**
      Returns the value for the property identified by a given key.
      */
-    public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToManyUnordered<D>>) -> Set<D> {
+    public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToManyUnordered<D>>) -> Set<D>? {
 
-        return self.snapshot[dynamicMember: member]
+        return self.object?[keyPath: member].value
+    }
+
+    /**
+     Returns the value for the property identified by a given key.
+     */
+    public subscript<V>(dynamicMember member: KeyPath<O, V>) -> V? {
+
+        return self.object?[keyPath: member]
     }
 }

Sources/NSManagedObjectContext+CoreStore.swift

@@ -106,7 +106,7 @@ extension NSManagedObjectContext {
     }
 
     @nonobjc
-    internal func objectsDidChangeObserver<U: AnyObject>(for observer: U) -> Internals.SharedNotificationObserver<Set<NSManagedObjectID>> {
+    internal func objectsDidChangeObserver<U: AnyObject>(for observer: U) -> Internals.SharedNotificationObserver<(updated: Set<NSManagedObjectID>, deleted: Set<NSManagedObjectID>)> {
 
         return self.userInfo(for: .objectsChangeObserver(U.self)) { [unowned self] in
 
@@ -114,11 +114,11 @@ extension NSManagedObjectContext {
                 notificationName: .NSManagedObjectContextObjectsDidChange,
                 object: self,
                 queue: .main,
-                sharedValue: { (notification) -> Set<NSManagedObjectID> in
+                sharedValue: { (notification) -> (updated: Set<NSManagedObjectID>, deleted: Set<NSManagedObjectID>) in
 
                     guard let userInfo = notification.userInfo else {
 
-                        return []
+                        return (updated: [], deleted: [])
                     }
                     var updatedObjectIDs: Set<NSManagedObjectID> = []
                     if let updatedObjects = userInfo[NSUpdatedObjectsKey] as? Set<NSManagedObjectID> {
@@ -129,7 +129,8 @@ extension NSManagedObjectContext {
 
                         updatedObjectIDs.formUnion(mergedObjects)
                     }
-                    return updatedObjectIDs
+                    let deletedObjectIDs: Set<NSManagedObjectID> = (userInfo[NSDeletedObjectsKey] as? Set<NSManagedObjectID>) ?? []
+                    return (updated: updatedObjectIDs, deleted: deletedObjectIDs)
                 }
             )
         }

Sources/ObjectRepresentation.swift

@@ -46,7 +46,7 @@ public protocol ObjectRepresentation {
     /**
      An instance that may be observed for object changes.
      */
-    func asLiveObject(in dataStack: DataStack) -> LiveObject<ObjectType>?
+    func asLiveObject(in dataStack: DataStack) -> LiveObject<ObjectType>
 
     /**
      A read-only instance in the `DataStack`.
@@ -82,10 +82,10 @@ extension DynamicObject where Self: ObjectRepresentation {
         return self.cs_id()
     }
 
-    public func asLiveObject(in dataStack: DataStack) -> LiveObject<Self>? {
+    public func asLiveObject(in dataStack: DataStack) -> LiveObject<Self> {
 
         let context = dataStack.unsafeContext()
-        return .init(objectID: self.cs_id(), context: context)
+        return LiveObject<Self>(objectID: self.cs_id(), context: context)
     }
 
     public func asReadOnly(in dataStack: DataStack) -> Self? {
@@ -111,12 +111,12 @@ extension DynamicObject where Self: ObjectRepresentation {
     public func asSnapshot(in dataStack: DataStack) -> ObjectSnapshot<Self>? {
 
         let context = dataStack.unsafeContext()
-        return .init(objectID: self.cs_id(), context: context)
+        return ObjectSnapshot<Self>(objectID: self.cs_id(), context: context)
     }
 
     public func asSnapshot(in transaction: BaseDataTransaction) -> ObjectSnapshot<Self>? {
 
         let context = transaction.unsafeContext()
-        return .init(objectID: self.cs_id(), context: context)
+        return ObjectSnapshot<Self>(objectID: self.cs_id(), context: context)
     }
 }

Sources/ObjectSnapshot.swift

@@ -51,10 +51,10 @@ public struct ObjectSnapshot<O: DynamicObject>: SnapshotResult, ObjectRepresenta
         return self.id
     }
     
-    public func asLiveObject(in dataStack: DataStack) -> LiveObject<O>? {
+    public func asLiveObject(in dataStack: DataStack) -> LiveObject<O> {
         
         let context = dataStack.unsafeContext()
-        return .init(objectID: self.id, context: context)
+        return LiveObject<O>(objectID: self.id, context: context)
     }
 
     public func asReadOnly(in dataStack: DataStack) -> O? {
@@ -70,21 +70,13 @@ public struct ObjectSnapshot<O: DynamicObject>: SnapshotResult, ObjectRepresenta
     public func asSnapshot(in dataStack: DataStack) -> ObjectSnapshot<O>? {
         
         let context = dataStack.unsafeContext()
-        if self.context == context {
-            
-            return self
-        }
-        return .init(objectID: self.id, context: context)
+        return ObjectSnapshot<O>(objectID: self.id, context: context)
     }
     
     public func asSnapshot(in transaction: BaseDataTransaction) -> ObjectSnapshot<O>? {
         
         let context = transaction.unsafeContext()
-        if self.context == context {
-            
-            return self
-        }
-        return .init(objectID: self.id, context: context)
+        return ObjectSnapshot<O>(objectID: self.id, context: context)
     }
 
 
@@ -93,7 +85,7 @@ public struct ObjectSnapshot<O: DynamicObject>: SnapshotResult, ObjectRepresenta
     public static func == (_ lhs: Self, _ rhs: Self) -> Bool {
 
         return lhs.id == rhs.id
-            && lhs.values == rhs.values
+            && lhs.valuesRef == rhs.valuesRef
     }
 
 
@@ -102,25 +94,32 @@ public struct ObjectSnapshot<O: DynamicObject>: SnapshotResult, ObjectRepresenta
     public func hash(into hasher: inout Hasher) {
 
         hasher.combine(self.id)
-        hasher.combine(self.values)
+        hasher.combine(self.valuesRef)
     }
 
 
     // MARK: Internal
 
-    internal init(objectID: O.ObjectID, context: NSManagedObjectContext) {
+    internal init?(objectID: O.ObjectID, context: NSManagedObjectContext) {
 
+        guard let values = O.cs_snapshotDictionary(id: objectID, context: context) else {
+
+            return nil
+        }
         self.id = objectID
-        self.context = context
-        self.values = O.cs_snapshotDictionary(id: objectID, context: context) as NSDictionary
+        self.values = values
     }
 
 
     // MARK: Private
 
     private let id: O.ObjectID
-    private let context: NSManagedObjectContext
-    private let values: NSDictionary
+    private var values: [String: Any]
+
+    private var valuesRef: NSDictionary {
+
+        return self.values as NSDictionary
+    }
 }
 
 
@@ -149,8 +148,16 @@ extension ObjectSnapshot where O: CoreStoreObject {
      */
     public subscript<V>(dynamicMember member: KeyPath<O, ValueContainer<O>.Required<V>>) -> V {
 
-        let key = String(keyPath: member)
-        return self.values[key] as! V
+        get {
+
+            let key = String(keyPath: member)
+            return self.values[key] as! V
+        }
+        set {
+
+            let key = String(keyPath: member)
+            self.values[key] = newValue
+        }
     }
 
     /**
@@ -158,8 +165,16 @@ extension ObjectSnapshot where O: CoreStoreObject {
      */
     public subscript<V>(dynamicMember member: KeyPath<O, ValueContainer<O>.Optional<V>>) -> V? {
 
-        let key = String(keyPath: member)
-        return self.values[key] as! V?
+        get {
+
+            let key = String(keyPath: member)
+            return self.values[key] as! V?
+        }
+        set {
+
+            let key = String(keyPath: member)
+            self.values[key] = newValue
+        }
     }
 
     /**
@@ -167,8 +182,16 @@ extension ObjectSnapshot where O: CoreStoreObject {
      */
     public subscript<V>(dynamicMember member: KeyPath<O, TransformableContainer<O>.Required<V>>) -> V {
 
-        let key = String(keyPath: member)
-        return self.values[key] as! V
+        get {
+
+            let key = String(keyPath: member)
+            return self.values[key] as! V
+        }
+        set {
+
+            let key = String(keyPath: member)
+            self.values[key] = newValue
+        }
     }
 
     /**
@@ -176,34 +199,66 @@ extension ObjectSnapshot where O: CoreStoreObject {
      */
     public subscript<V>(dynamicMember member: KeyPath<O, TransformableContainer<O>.Optional<V>>) -> V? {
 
-        let key = String(keyPath: member)
-        return self.values[key] as! V?
+        get {
+
+            let key = String(keyPath: member)
+            return self.values[key] as! V?
+        }
+        set {
+
+            let key = String(keyPath: member)
+            self.values[key] = newValue
+        }
     }
 
     /**
      Returns the value for the property identified by a given key.
      */
-    public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToOne<D>>) -> D? {
+    public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToOne<D>>) -> D.ObjectID? {
 
-        let key = String(keyPath: member)
-        return self.values[key] as! D?
+        get {
+
+            let key = String(keyPath: member)
+            return self.values[key] as! D.ObjectID?
+        }
+        set {
+
+            let key = String(keyPath: member)
+            self.values[key] = newValue
+        }
     }
 
     /**
      Returns the value for the property identified by a given key.
      */
-    public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToManyOrdered<D>>) -> [D] {
+    public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToManyOrdered<D>>) -> [D.ObjectID] {
 
-        let key = String(keyPath: member)
-        return self.values[key] as! [D]
+        get {
+
+            let key = String(keyPath: member)
+            return self.values[key] as! [D.ObjectID]
+        }
+        set {
+
+            let key = String(keyPath: member)
+            self.values[key] = newValue
+        }
     }
 
     /**
      Returns the value for the property identified by a given key.
      */
-    public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToManyUnordered<D>>) -> Set<D> {
+    public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToManyUnordered<D>>) -> Set<D.ObjectID> {
 
-        let key = String(keyPath: member)
-        return self.values[key] as! Set<D>
+        get {
+
+            let key = String(keyPath: member)
+            return self.values[key] as! Set<D.ObjectID>
+        }
+        set {
+
+            let key = String(keyPath: member)
+            self.values[key] = newValue
+        }
     }
 }

Sources/Relationship.swift

@@ -315,7 +315,7 @@ public enum RelationshipContainer<O: CoreStoreObject> {
 
         internal var valueForSnapshot: Any {
 
-            return self.value as Any
+            return self.value?.objectID() as Any
         }
         
         
@@ -611,7 +611,7 @@ public enum RelationshipContainer<O: CoreStoreObject> {
 
         internal var valueForSnapshot: Any {
 
-            return self.value as Any
+            return self.value.map({ $0.objectID() }) as Any
         }
         
         
@@ -912,7 +912,7 @@ public enum RelationshipContainer<O: CoreStoreObject> {
 
         internal var valueForSnapshot: Any {
 
-            return self.value as Any
+            return Set(self.value.map({ $0.objectID() })) as Any
         }