Expo Client crashes on iOS 13.4 when toggling Performance Monitor

🐛 Bug Report

First off, I’m not sure if this is the right place to report issues with the client itself but I can’t find anywhere else.

Since updating my iPhone (and iOS Simulator) to iOS 13.4, the Expo Client crashes when I try to toggle Performance Monitor. I can reproduce this on my iPhone (iOS 13.4, iPhone XS) and MacBook (macOS 10.15.4, MacBook Pro 16").

Environment

Expo CLI 3.15.5 environment info:
  System:
    OS: macOS 10.15.4
    Shell: 5.7.1 - /bin/zsh
  Binaries:
    Node: 12.16.1 - ~/.n/bin/node
    Yarn: 1.22.4 - ~/.yarn/bin/yarn
    npm: 6.14.3 - ~/.n/bin/npm
  IDEs:
    Xcode: 11.4/11E146 - /usr/bin/xcodebuild
  npmPackages:
    expo: ^36.0.0 => 36.0.0
    react: 16.9.0 => 16.9.0
    react-native: https://github.com/expo/react-native/archive/sdk-36.0.0.tar.gz => 0.61.4
  npmGlobalPackages:
    expo-cli: 3.15.5

App target: iOS

Steps to Reproduce

• Trigger the Expo menu in the Expo Client (by shaking or two-finger pressing)
• Tap Show Performance Monitor

To be sure it wasn’t anything related to code, I reverted to some working code from yesterday and the issue persists.

Expected Behavior

The Performance Monitor should show in the top corner as it always does

Actual Behavior

The Expo Client app completely crashes you’re taken back to the iOS home screen. I’ve tested this on both macOS via the iOS Simulator and on iOS on my iPhone.

Reproducible Demo

I’m not able to share any code from my project but if I get chance after work, I’ll try to strip out as much as I can on another branch and create a snack or something. For now, though, it seems unrelated to any code as it was working this morning and since upgrading to the latest macOS and iOS, the Expo Client crashes when toggling the Performance Monitor.

[nextriot]

Now that it’s seemingly been fixed upstream, what’s required to get it working in Expo?

[IjzerenHein]

@darrylyoung Yep lets see how this issue develops. I’ve reported it upstream to RN with a detailed description. It seems that setting options in the JavaScriptCore is no longer supported after the VM has been initialized. So a different strategy is needed if we still want to support VM GC tracking.