I'm trying to get a project working that syncs SwiftData with iCloud. I first tried adding SwiftData and CloudKit to an existing project that has a model that looks like this. Its also setup as a modelContainer in the main app file. It returns this error "Fatal error: failed to find a currently active container for Book". I have selected a container in the iCloud capability also. I then just tried to create a new project that included SwiftData from the beginning. That one, all i did was select a container since the rest of the setup was already done and its giving an error that says "Could not create ModelContainer: SwiftDataError(error: SwiftData.SwiftDataError.Error.loadIssueModelContainer)" . Any insight would be appreciated.

import SwiftUI
import SwiftData

@main
struct book_managerApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
        .modelContainer(for: Book.self)
    }
}

@Model class Book {
    var isbn: String
    var title: String
    var authors: [String]
    var publisher: String
    var publishDate: String
    var bookDescription: String
    var pageCount: Int
    var categories: [String]
    var smallThumbnail: String
    var thumbnail: String
    var dateScanned: Date = Date.now
    var seriesName: String = ""
    var seriesNumber: Int = 0
    var readDates: [Date] = []
    var isOwned: Bool = true

    init(isbn: String, title: String, authors: [String], publisher: String, publishDate: String, bookDescription: String, pageCount: Int, categories: [String], smallThumbnail: String? = nil, thumbnail: String? = nil) {
        self.isbn = isbn
        self.title = title
        self.authors = authors
        self.publisher = publisher
        self.publishDate = publishDate
        self.bookDescription = bookDescription
        self.pageCount = pageCount
        self.categories = categories
        self.smallThumbnail = smallThumbnail ?? ""
        self.thumbnail = thumbnail ?? ""
    }
}

I believe for Cloudkit sync to work, all parts of your Book Model class must be given a default value or be optional so

@Model class Book {
    var isbn: String = "unknown"
    var title: String = "blank"
    var authors: [String] = []
    var publisher: String = "anonymous"

and so on..