`.destination(.dismiss)` not called if using `@ReducerCaseIgnored` with `Identifiable` model in UIKit

[areschoug]

Description

When using @ReducerCaseIgnored with a model that conforms to Identifiable, the .destination(.dismiss) action is not triggered when the view controller is dismissed.

struct IdentifiableModel: Identifiable, Equatable {
      let id: String
}

struct NotIdentifiableModel: Equatable {
      let id: String
}
…

@Reducer
enum Destination {
      @ReducerCaseIgnored
      case identifiable(IdentifiableModel)

      @ReducerCaseIgnored
      case notIdentifiable(NotIdentifiableModel)
}

…

// Does _not_ trigger `.destination(.dismiss)` when `IdentifiableModelViewController` is dismissed.
present(
      item: $store.scope(state: \.destination?.identifiable, action: \.destination.identifiable)
) { store in
      IdentifiableModelViewController(identifiableModel: store.withState { $0 })
}

// _Does_ trigger `.destination(.dismiss)` when `NotIdentifiableModelViewController` is dismissed.
present(
      item: $store.scope(state: \.destination?.notIdentifiable, action: \.destination.notIdentifiable)
) { store in
      NotIdentifiableModelViewController(notIdentifiableModel: store.withState { $0 })
}

From my debugging with breakpoints, it appears that this line evaluates to true (both nil) if the model is not Identifiable, and false when the model is Identifiable (id is nil while _identifiableID(childState) is set from the model's id).

This is within the swift-composable-architecture repository, but since the issue seems to be related to navigation behavior, I’ve filed the issue here.

Checklist

• I have determined whether this bug is also reproducible in a vanilla SwiftUI project.
• If possible, I've reproduced the issue using the main branch of this package.
• This issue hasn't been addressed in an existing GitHub issue or discussion.

Expected behavior

The .destination(.dismiss) action should be called, and destination should be set to nil.

Actual behavior

The .destination(.dismiss) action is not called.

Steps to reproduce

You can reproduce the issue using this repository/file.

SwiftUI Navigation version information

2.3.1

Destination operating system

iOS 18.5

Xcode version information

16.2 (16C5032a)

Swift Compiler version information

swift-driver version: 1.115.1 Apple Swift version 6.0.3 (swiftlang-6.0.3.1.10 clang-1600.0.30.1)
Target: arm64-apple-macosx15.0

[acosmicflamingo]

As of 1.22.4, the line from swift-composable-architecture is this one: https://github.com/pointfreeco/swift-composable-architecture/blob/1.22.2/Sources/ComposableArchitecture/Observation/Store%2BObservation.swift#L464 (the original points to a static line in main branch, so it's no longer accurate)

[acosmicflamingo]

Although the behavior does involve navigation, I think the actual issue is reflected in this ticket from swift-composable-architecture: pointfreeco/swift-composable-architecture#3451.

I believe this to be the case too because even though I have a swift-navigation branch that comprises a fix to the currently-broken onDismiss behavior, when I point my local swift-composable-architecture repo to this branch, my TCA app still encounters the issue where destination(.dismiss) actions do not nil-out the destination property. Therefore, this ticket should be closed, in favor of the swift-composable-architecture one.