Codable class does not conform to protocol Decodable

Question

Why am I getting a "Type 'Bookmark' does not conform to protocol 'Decodable'" error message?

class Bookmark: Codable {
   weak var publication: Publication?
   var indexPath: [Int]
   var locationInText = 0

   enum CodingKeys: String, CodingKey {
      case indexPath
      case locationInText
   }

   init(publication: Publication?, indexPath: [Int]) {
      self.publication = publication
      self.indexPath = indexPath
   }
}

I do not wish to save the publication var since the Publication owns the Bookmark but the bookmark needs to know which Publication it belongs to. The decode init of Publication will set the bookmark reference to itself.

Answer 1

Why am I getting a "Type 'Bookmark' does not conform to protocol 'Decodable'" error message

It's either because Publication isn't Decodable (you have not shown what it is, so it's hard to tell) or because of the weak designation on publication.

Either way, it's easy to fix: you just need to implement init(from:) to complete the implementation of Decodable; the compiler is simply telling you that this implementation cannot be synthesized.