Occasional crash on `context.save()`

Recently, I noticed many crashes reported daily for context.save() in my code. I tried to resolve the issue by refactoring some of the code. My key change is to use context.performAndWait to fetch Core Data objects instead of passing them around.

I refactored the code to pass NSManagedObjectID around instead of NSManagedObject itself because NSManagedObjectID is thread-safe.

However, even after the refactor, the issue is still. The crash log is attached as below.

I'm confused that it doesn't crash on all devices so I have no clue to find the pattern of the crashes. I also enabled -com.apple.CoreData.ConcurrencyDebug 1 on my local dev box, but seems the error cannot be caught.

The new code (after I refactored) still causes the crash:

    private func update(movements: [InferredMovement], from visitOutObjectId: NSManagedObjectID, to visitInObjectId: NSManagedObjectID?) {
        let context = PersistenceController.shared.container.viewContext
        context.performAndWait {
            guard let visitOut = try? context.existingObject(with: visitOutObjectId) as? Visit else {
                return
            }

            var visitIn: Visit?
            if let visitInObjectId {
                visitIn = try? context.existingObject(with: visitInObjectId) as? Visit
            }

            visitOut.movementsOut.forEach { context.delete($0) }
            visitIn?.movementsIn.forEach { context.delete($0) }

            for inferred in movements {
                let movement = Movement(context: context)
                movement.type = inferred.type
                movement.interval = inferred.interval
                movement.visitFrom_ = visitOut
                movement.visitTo_ = visitIn
            }

            visitOut.objectWillChange.send()
            context.saveIfNeeded()
        }
    }

Note, saveIfNeeded() is an extension function implemented as:

extension NSManagedObjectContext {
    
    /// Only performs a save if there are changes to commit.
    @discardableResult
    public func saveIfNeeded() -> Error? {
        guard hasChanges else {
            return nil
        }
        do {
            try save()
            return nil
        } catch {
            defaultLogger.error("Core Data Error: Failed to save context")
            return error
        }
    }
}