CRASH: Could not cast value of type 'Observation.ObservationRegistrar' to 'Perception._PerceptionRegistrar'

[iharandreyev]

Description

The error in question happens when I'm trying to test the following feature

import ComposableArchitecture
import Foundation

@ObservableState
enum RemoteResourceState<Value> {
    case none
    case loading
    case loaded(Value)
    case failed(Error)
}

extension RemoteResourceState: Equatable where Value: Equatable {
    static func == (lhs: Self, rhs: Self) -> Bool {
        switch (lhs, rhs) {
        case (.none, .none): return true
        case (.loading, .loading): return true
        case let (.loaded(lhs), .loaded(rhs)):
            return lhs == rhs
        case let (.failed(lhs), .failed(rhs)):
            return "\(lhs)" == "\(rhs)"
        default:
            return false
        }
    }
}

enum RemoteResourceAction<Value> {
    case load
    case succeed(Value)
    case fail(Error)
}

extension RemoteResourceAction: Equatable where Value: Equatable {
    static func == (lhs: Self, rhs: Self) -> Bool {
        switch (lhs, rhs) {
        case (.load, .load): return true
        case let (.succeed(lhs), .succeed(rhs)):
            return lhs == rhs
        case let (.fail(lhs), .fail(rhs)):
            return "\(lhs)" == "\(rhs)"
        default:
            return false
        }
    }
}

struct RemoteResource<Value>: Reducer {
    typealias State = RemoteResourceState<Value>
    typealias Action = RemoteResourceAction<Value>

    var body: some ReducerOf<Self> {
        EmptyReducer()
    }
}

with a test below

import XCTest
import ComposableArchitecture
@testable import MyApp

final class RemoteResourceTests: XCTestCase {
    func testLoadFirst() async {
        typealias SUT = RemoteResource<TestResource>

        let store = TestStoreOf<SUT>(
            initialState: .none,
            reducer: SUT.init
        )

        await store.send(.load) { state in
            state = .loading
        }
    }
}

// MARK: - Helpers

private struct TestResource: Identifiable, Equatable {
    let id: Int = UUID().hashValue
}

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.
• [X] This issue hasn't been addressed in an existing GitHub issue or discussion.

Expected behavior

Test fails with an invalid behavior error

Actual behavior

Test crashes with Could not cast value of type 'Observation.ObservationRegistrar' to 'Perception._PerceptionRegistrar' error in Perception/PerceptionRegistrar.swift:52

Steps to reproduce

Run the code in the description

The Composable Architecture version information

1.10.4

Destination operating system

iOS 15.0

Xcode version information

15.4

Swift Compiler version information

swift-driver version: 1.90.11.1 Apple Swift version 5.10 (swiftlang-5.10.0.13 clang-1500.3.9.4)
Target: arm64-apple-macosx14.0

[iharandreyev]

The issue occurs when I use iOS 17.5 simulator as a test run destination. When running on iOS 15.5 simulator, there's no crash

[mbrandonw]

Hi @iharandreyev, I am not able to reproduce this. I have run it in a variety of simulators and it all seems to work fine. Can you please provide a project that demonstrates the problem?

I am also going to convert this to a discussion for the time being because it's not clear there is an actual issue with the library. Let's continue the conversation over there.