RN 0.76 Regression - jsi::JSError is not visually visible to the end user

[jpudysz]

Description

I began developing a new version of react-native-unistyles as soon as the RC for 0.75 was released. During this time, I added a lot of JSI code that has been tested dozens of times.

Yesterday, I upgraded my example project from RN 0.75.4 to 0.76.0 and noticed that jsi::JSError is no longer propagated to the Xcode console or shown as a red screen to the user.

I have no information on Android since I haven't created bindings for it yet.

I prepared two reproducers with minimal code, along with screenshots showing results for RN 0.75.4 and 0.76.

Steps to reproduce

1. Create new Bare RN 0.76 project
2. Add any native code / library that throws jsi::JSError
3. An error is thrown, but there is no visual indication to confirm it

For my 0.76 reproducer:

1. Please go to Pods/Development Pods/Unistyles/cxx/hybridObjects/HybridStyleSheet.cpp
2. Add breakpoint at line 18

helpers::assertThat(rt, count == 2, "StyleSheet.create expected to be called with one argument.");

3. Verify that jsi::JSError is thrown

Here is my 0.75.4 reproducer, where everything works fine:
https://github.com/jpudysz/rn-0.75-jsi-reproducer

React Native Version

0.76.0

Affected Platforms

Runtime - iOS

Output of npx react-native info

System:
  OS: macOS 15.0
  CPU: (12) arm64 Apple M3 Pro
  Memory: 728.19 MB / 36.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 20.15.0
    path: /usr/local/bin/node
  Yarn:
    version: 1.22.22
    path: /opt/homebrew/bin/yarn
  npm:
    version: 10.7.0
    path: /usr/local/bin/npm
  Watchman:
    version: 2024.06.24.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.15.2
    path: /opt/homebrew/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 24.0
      - iOS 18.0
      - macOS 15.0
      - tvOS 18.0
      - visionOS 2.0
      - watchOS 11.0
  Android SDK:
    API Levels:
      - "23"
      - "28"
      - "29"
      - "30"
      - "33"
      - "34"
      - "35"
    Build Tools:
      - 30.0.3
      - 34.0.0
      - 35.0.0
    System Images:
      - android-23 | ARM 64 v8a
      - android-28 | ARM 64 v8a
      - android-29 | ARM 64 v8a
      - android-30 | ARM 64 v8a
      - android-30 | Google APIs ARM 64 v8a
      - android-34 | Android TV ARM 64 v8a
      - android-34 | ARM 64 v8a
      - android-35 | Google APIs ARM 64 v8a
    Android NDK: Not Found
IDEs:
  Android Studio: 2024.2 AI-242.23339.11.2421.12483815
  Xcode:
    version: 16.0/16A242d
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.11
    path: /usr/bin/javac
  Ruby:
    version: 2.6.10
    path: /usr/bin/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 15.0.0-alpha.2
    wanted: 15.0.0-alpha.2
  react:
    installed: 18.3.1
    wanted: 18.3.1
  react-native:
    installed: 0.76.0
    wanted: 0.76.0
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true

Stacktrace or Logs

No crash

Reproducer

https://github.com/jpudysz/rn-0.76-jsi-reproducer

Screenshots and Videos

RN 0.75.4

RN 0.76.0

[cipolleschi]

This issue uses NitroModules and the error is thrown when the ReactInstance calls loadScript right at the beginning of the execution.

I would like to have a reproducer with a vanilla React Native, with no NitroModules and a simple C++ module, to be able to understand better what's going on.
As of now, I can't exclude that perhaps NitroModules are not yet compatible with 0.76.

(They also don't build on Android...)

[jpudysz]

Sorry, it was just easier to add my code rather than create it from scratch. I'm experiencing the same behavior with Turbo Modules.

Pushed new commit: https://github.com/jpudysz/rn-0.76-jsi-reproducer

Result:

[cipolleschi]

Thanks for updating the reproducer!

I can verify that if the error happens early, it is not bubbled to the redbox.
Moving the throwing line inside a component, makes it work fine.

I believe that this is because when we throw the error too early, there is no error pipeline ready to catch it.

QQ: when you were trying in 0.75, were you on the new or on the old architecture?

[jpudysz]

Updated RN 0.75.4 repro with the same code: https://github.com/jpudysz/rn-0.75-jsi-reproducer
It also runs New Arch, and I can see the early JSI error: