Issue with WithPerceptionTracking and ObservableState Not Working Properly in TestFlight (iOS 16, TCA 1.12.1)

[d0yvn]

Description

Hello,

I’m encountering an issue while using your TCA library in our iOS project, and I’d like to ask for your help.

Environment: iOS 16, TCA 1.12.1
Issue: After uploading our app to TestFlight for testing, we noticed that certain view behaviors (e.g., hiding a view after a button click or during a scroll) did not work as expected. However, everything works fine in debug mode.
Used Code: WithPerceptionTracking, ObservableState
Test Results:
On devices running iOS 16, the issue occurs in TestFlight builds.
On devices running iOS 17 and iOS 18, everything works correctly, even in TestFlight builds.
Questions:

Test Setup:

To investigate further, I created a simplified test environment. The setup is straightforward:

• When a button is clicked, the state (scene) is updated, and additional text should appear on the screen.
• The state update is confirmed through logs, so we know the state is changing as expected.
• I tested this by switching the build configuration to Release (not just via TestFlight).

Test Results:

1. iOS 16.4 Simulator:

• Logs confirm that the state is updated when the button is clicked.
• However, the view does not reflect the state change — the additional text never appears.

2. iOS 18.2 Simulator:

• Everything works as expected.
• The additional text appears correctly when the button is clicked, reflecting the state update.

I’ve attached two videos:

• the issue on iOS 16.4.

Simulator.Screen.Recording.-.iPhone.14.-.2025-03-05.at.10.03.00.mp4

• One showing the correct behavior on iOS 18.2.

Simulator.Screen.Recording.-.iPhone.16.Pro.-.2025-03-05.at.10.14.10.mp4

Here’s a simple test code I wrote.

import SwiftUI
import ComposableArchitecture

public struct SampleView: View {
    public let store: StoreOf<SampleReducer>
    
    public init(store: StoreOf<SampleReducer>) {
        self.store = store
    }
    
    public var body: some View {
        WithPerceptionTracking {
            VStack {
                Button {
                    store.send(.button1)
                } label: {
                    Text("button1")
                        .font(.system(size: 16, weight: .bold))
                        .frame(maxWidth: .infinity)
                        .frame(height: 56)
                }
                
                Button {
                    store.send(.button2)
                } label: {
                    Text("button1")
                        .font(.system(size: 16, weight: .bold))
                        .frame(maxWidth: .infinity)
                        .frame(height: 56)
                }
                
                contents
            }
        }
    }
    
    @ViewBuilder
    var contents: some View {
        WithPerceptionTracking {
            switch store.scene {
            case .first:
                EmptyView()
            case .second:
                Text("test1")
            case .third:
                Text("test2")
            }
        }
    }
}

@Reducer
public struct SampleReducer {
    @ObservableState
    public struct State {
        var scene: Scene = .first {
            didSet {
                print("[log] - scene \(scene)")
            }
        }
        
        public init(scene: Scene) {
            self.scene = scene
        }
    }
    
    public enum Scene {
        case first
        case second
        case third
    }
    
    public enum Action {
        case button1
        case button2
    }
    
    public var body: some ReducerOf<Self> {
        Reduce { state, action in
            switch action {
            case .button1:
                state.scene = .second
                return .none
            case .button2:
                state.scene = .third
                return .none
            }
        }
    }
    
    public init() { }
}

Are there any known issues with using WithPerceptionTracking and ObservableState in this context?
Do you have any suggestions or potential fixes we can try?
Has this issue been reported before?
We would like to use WithPerceptionTracking and ObservableState in our production app, but this issue is blocking us. Any guidance or insights would be greatly appreciated.

Thank you so much for your support!

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

No response

Actual behavior

No response

Reproducing project

No response

The Composable Architecture version information

No response

Destination operating system

No response

Xcode version information

No response

Swift Compiler version information

[mbrandonw]

Hi @d0yvn, your code seems to work just fine for me. This is running in an iOS 16.4 simulator:

Screen.Recording.2025-07-11.at.9.59.17.AM.mov

Can you share a full project that reproduces the problem?

Since this isn't an issue with the library I am going to convert it to a discussion. Please feel free to continue the conversation over there!