Goals

Realm should never crash a React Native app.

I suspect that we need to tell the JSCore engine that an unhandled exception happened during the execution of the callback.

I suspect this also happens if the error is thrown from other callbacks that we call from C++, therefore the following issues probably share the same root cause: https://github.com/realm/realm-js/issues/2029, https://github.com/realm/realm-js/issues/1439, https://github.com/realm/realm-js/issues/2233.

Expected Results

When an error is thrown from a callback added as a listener on a Results object, I expect an uncaught exception to be handled (resulting in a black screen with a red top-bar while in development mode).

Actual Results

When an error is thrown from a callback added as a listener on a Results object, the app crashes!

Steps to Reproduce & Code Sample

// App.js

import React, { Component } from 'react';
import { View, Text } from 'react-native';
import Realm from 'realm'

export default class App extends Component {
  componentDidMount() {
    const realm = new Realm({
        schema: [{
            name: "Singleton",
            properties: { value: "string" },
        }],
    });

    realm.objects("Singleton").addListener(() => {
        throw new Error("Change happened!");
    });
  }

  render() {
    return <View><Text>App loaded ...</Text></View>;
  }
}

Version of Realm and Tooling

• Realm JS SDK Version: 2.6.0
• Node or React Native: React Native (confirmed on iOS)
• Client OS & Version: N/A
• Which debugger for React Native: None