ios – NSFetchRequest Assortment.first At all times Returning Entity from Empty Retailer

I’ve the next code that at all times returns an occasion of Member, when it ought to be returning nil. It doesn’t matter what I enter for username, and regardless of what number of occasions I delete the app from the simulator, the throw is at all times triggered from the create operate.

class MemberViewModel: ObservableObject {
    ...

    func create() throws -> Void {
        let context = Self.container.viewContext

        if entity!.username != nil {
            if attempt Self.fetch(username: entity!.username!) != nil {
                throw MemberError.UserExists(username: entity!.username!)
            }

            if context.hasChanges {
                attempt context.save()
            }
        }
    }

    static non-public func fetch(username: String) throws -> Member? {
        let fetchRequest: NSFetchRequest<Member> = Member.fetchRequest()
        let context = Self.container.viewContext

        fetchRequest.predicate = NSPredicate(format: "username[c] == %@", username)
        return attempt? context.fetch(fetchRequest).first
    }

    ...
}

extension MemberViewModel {
    public enum MemberError: Error {
        case UserExists(username: String)
    }
}

The calling code seems like:

extension MemberView {
    func save() -> Void {
        if (identify.isEmpty) {
            nameError = "A reputation should be offered to proceed"
        }

        if (username.isEmpty) {
            usernameError = "A username or e-mail should be offered"
        }

        if (nameError != nil || usernameError != nil) {
            return
        }

        do {
            let mvm = MemberViewModel(identify: identify, username: username, password: password, age: age, position: position, admin: admin, imageName: AVATARS[selectedImage], imageTint: selectedTint)
            attempt mvm.create()

            web page = nil
        } catch MemberViewModel.MemberError.UserExists(let username) {
            usernameError = "The username (username) is already taken"
        } catch {
        }
    }
}