[Expo 51 Beta][iOS] Expo Go app crashes when switching back to previous tab

[nam-aalto]

Minimal reproducible example

https://github.com/ntgn81/expo51-router-crash

Which package manager are you using? (Yarn is recommended)

npm

If the issue is web-related, please select the bundler (web.bundler in the app.json)

None

Summary

Problem

Expo Go app crashes when navigating back to Tab 1 on iOS Simulator

Steps

• npx expo start
• Open app in iOS simulator
• Click on Tab 2
• Click on Tab 1
• App crashes

Extra finding

The app does not crash if react-native-reanimated is imported.

Uncommenting the import "react-native-reanimated" in app/_layout.tsx will make the tab switch work without crashing.

Environment

expo-env-info 1.2.0 environment info:
System:
  OS: macOS 14.4
  Shell: 5.9 - /bin/zsh
Binaries:
  Node: 18.18.0 - ~/.nvm/versions/node/v18.18.0/bin/node
  npm: 9.8.1 - ~/.nvm/versions/node/v18.18.0/bin/npm
  Watchman: 2024.04.08.00 - /opt/homebrew/bin/watchman
Managers:
  CocoaPods: 1.15.2 - /opt/homebrew/bin/pod
SDKs:
  iOS SDK:
    Platforms: DriverKit 23.4, iOS 17.4, macOS 14.4, tvOS 17.4, visionOS 1.1, watchOS 10.4
IDEs:
  Android Studio: 2023.2 AI-232.10300.40.2321.11668458
  Xcode: 15.3/15E204a - /usr/bin/xcodebuild
npmPackages:
  expo: ~51.0.0-preview.7 => 51.0.0-preview.7 
  expo-router: 3.5.3 => 3.5.3 
  react: 18.2.0 => 18.2.0 
  react-dom: 18.2.0 => 18.2.0 
  react-native: 0.74.0 => 0.74.0 
  react-native-web: ~0.19.10 => 0.19.11 
npmGlobalPackages:
  eas-cli: 7.6.1
Expo Workflow: managed

[expo-bot]

Thank you for filing this issue!
This comment acknowledges we believe this may be a bug and there’s enough information to investigate it.
However, we can’t promise any sort of timeline for resolution. We prioritize issues based on severity, breadth of impact, and alignment with our roadmap. If you’d like to help move it more quickly, you can continue to investigate it more deeply and/or you can open a pull request that fixes the cause.

[marklawlor]

Upstream react-native-reanimated issue: software-mansion/react-native-reanimated#5947

[nam-aalto]

Hmm, is it reanimated problem? The reproducible code does not include reanimated. Including reanimated fixes the crash for me.

[brentvatne]

@nam-aalto - react-native-screens calls into reanimated in some places

[marklawlor]

I'm going to close this issue and move the conversation to #28618

We're unsure if a fix for this will be ready at the launch of SDK51. A work around is detailed in the new issue