Referencing initializer 'init(wrappedValue:_:nilValidation:)' on 'Validated' requires that 'Published<String>' conform to 'Optionalable'

[JulesMoorhouse]

ValidatedPropertyKit Environment

• ValidatedPropertyKit version:
  0.0.5

• macOS version:
  11.6.2

• Xcode version:
  13.2.1

• Dependency manager (Carthage, CocoaPods, SPM, Manually):
  SPM

What did you do?

I'm using a view model.

import CoreData
import Foundation
import ValidatedPropertyKit

extension EditView {
    class ViewModel: NSObject, ObservableObject {
        let item: Item
        let add: Bool
        let hasRelationship: Bool

        private let dataController: DataController

        @Validated(!.isEmpty)
        @Published var title = "" <= error
        // @Published var title: String <= error 

What did you expect to happen?

To access the variable as shown in the readme examples.

What happened instead?

Error....

Referencing initializer 'init(wrappedValue:_:nilValidation:)' on 'Validated' requires 
that 'Published<String>' conform to 'Optionalable'

I'm not sure why this is occurring?

Thanks in advance.

[SvenTiigi]

Hi @JulesMoorhouse,

As you are applying the @Validated property wrapper to an @Published declared property the resulting type of the Validated property wrapper is a Published<String> which results in a compile error as the isEmpty validation rule can only be applied to types that conform to the Collection protocol.

ValidatedPropertyKit/Sources/Validation/Validation+Collection.swift

Line 16 in 1fc8adb

static var isEmpty: Self {

PS: The error message that Xcode shows is a little bit confusing the correct error message should be:

Static property 'isEmpty' requires that 'Published<String>' conform to 'Collection'

[JulesMoorhouse]

Thanks for your reply @SvenTiigi what do you suggest I do to fix the problem.

[SvenTiigi]

As the Published type does not expose a wrapped value there is sadly no way to access the underlying value to validate.