Crash on nil property

[yonaskolb]

Summary

We've been seeing a crash after using the generated inits and then accessing a nil property. It occurs within DataDict.swift
The crash is on line 78 but I believe the issue is from line 91, where an AnyHashable? is unwrapped unsuccessfully and is then passed along as AnyHashable with a value of nil on line 95. I don't know if it's an issue in the inits not managing nil values properly or a swift dynamic casting issue with the functions here.

lldb on line 95:

(lldb) po data
▿ AnyHashable(nil)
  - value : nil

Here is the full generated model we're trying to initialise. A bunch of properties have been removed to simplify it:

public struct AppPageHeroSectionData: ShopAPI.SelectionSet, Fragment {
  public static var fragmentDefinition: StaticString { """
    fragment AppPageHeroSectionData on AppPageHeroSection {
      __typename
      id
      personalizedMessaging {
        __typename
        id
        title
      }
    }
    """ }

  public let __data: DataDict
  public init(_dataDict: DataDict) { __data = _dataDict }

  public static var __parentType: ApolloAPI.ParentType { ShopAPI.Objects.AppPageHeroSection }
  public static var __selections: [ApolloAPI.Selection] { [
    .field("__typename", String.self),
    .field("id", ShopAPI.ID.self),
    .field("personalizedMessaging", PersonalizedMessaging?.self),
  ] }

  public var id: ShopAPI.ID { __data["id"] }
  public var personalizedMessaging: PersonalizedMessaging? { __data["personalizedMessaging"] }

  public init(
    id: ShopAPI.ID,
    personalizedMessaging: PersonalizedMessaging? = nil
  ) {
    self.init(_dataDict: DataDict(data: [
      "__typename": ShopAPI.Objects.AppPageHeroSection.typename,
      "id": id,
      "personalizedMessaging": personalizedMessaging._fieldData,
      "__fulfilled": Set([
        ObjectIdentifier(Self.self)
      ])
    ]))
  }

  /// PersonalizedMessaging
  ///
  /// Parent Type: `PersonalizedMessagingTextBlock`
  public struct PersonalizedMessaging: ShopAPI.SelectionSet {
    public let __data: DataDict
    public init(_dataDict: DataDict) { __data = _dataDict }

    public static var __parentType: ApolloAPI.ParentType { ShopAPI.Objects.PersonalizedMessagingTextBlock }
    public static var __selections: [ApolloAPI.Selection] { [
      .field("__typename", String.self),
      .field("id", ShopAPI.ID.self),
      .field("title", String.self),
    ] }

    public var id: ShopAPI.ID { __data["id"] }
    public var title: String { __data["title"] }

    public init(
      id: ShopAPI.ID,
      title: String
    ) {
      self.init(_dataDict: DataDict(data: [
        "__typename": ShopAPI.Objects.PersonalizedMessagingTextBlock.typename,
        "id": id,
        "title": title,
        "__fulfilled": Set([
          ObjectIdentifier(Self.self)
        ])
      ]))
    }
  }
}

Version

Apollo: 1.1.0-beta
Xcode: 14.2
Swift: 5.7.2
iOS: 16.2

Steps to reproduce the behavior

Create a SelectionSet that has an optional SelectionSet property, initialise that to nil and access it.

let section = AppPageHeroSectionData(
  id: "1",
  personalizedMessaging: nil
)
let message = section.personalizedMessaging // expect nil but it crashes

Logs

No response

Anything else?

This may be related to the following 2 issues:

• DataDict subscript function crashes on iOS 14.4 and under #2668 (Not this is on iOS 16.2)
• Retrieving optional field containing null in cache during ReadWriteTransaction causes crash #2861

[AnthonyMDev]

Thanks for this awesome report and your PR! I'll be looking into this today and let you know what I come up with.

[AnthonyMDev]

This is now fixed on main and will be included in the 1.1 GA release! Thanks so much @yonaskolb