Android crash on shims import

[jcbdev]

Describe the bug
Whilst running the shims checks on android the following line causes an entire app crash on a real android device (javascriptcore crash). Works fine in the IOS simulator and works fine if you use hermes

var forms = ["NFD", "NFC", "NFKD", "NFKC"];
        for (var i = 0; i < forms.length; i++) {
            try {
                // Simple test that catches invalid normalization
                if ("test".normalize(forms[i]) !== "test") {
                    throw new Error("failed to normalize");
                }

                // Some platforms seem to only fail when normalizing
                // specific code planes, so add those here as they
                // come up.
                //               "hangul"
                const checks = [ "\ud55c\uae00" ];
                for (var j = 0; j < checks.length; j++) {
                    checks[j].normalize(forms[i]);  <----- THIS CHECK CRASHES ANDROID DEVICE
                }
            } catch(error) {
                missing.push(forms[i]);
            }
        }

Even if I import unorm from npm package prior to loading the shim the same issue still occurs

import 'react-native-get-random-values';
import './global.js';
import unorm from 'unorm';
// // eslint-disable-next-line no-extend-native
String.prototype.normalize = function(form) {
  var func = unorm[(form || 'NFC').toLowerCase()];
  if (!func) {
    throw new RangeError('invalid form - ' + form);
  }
  return func(this);
};
import '@ethersproject/shims/dist/index';

Reproduction steps
see above

Environment:
React Native v0.63 (react-native-get-random-values and node-libs-browser)

[robertmagier]

We are getting the same issue. It crashes on import.

[Sotatek-NinhTran]

I'm getting the same issue. It crashes on Android (real devices) when import shims.

[ricmoo]

The error cannot be caught? What is the error that occurs (in the OS or anywhere) if any?

I will back out the changes. It sounds like it probably isn’t helping the case where the OS doesn’t support Korean anyways.

[jcbdev]

@ricmoo No it cannot be caught as it crashes the whole application (not throws a javascript error). The whole JavscriptCore engine crashes and the app is killed immediately by the OS.

You can see a crashdump if you adb logcat but I am not around an android device currently.

EDIT: I did also try hacking the shims node module to put a try catch around the line but it doesn't work because it's an entire engine crash.

[ricmoo]

Fixed in 5.3.0.

I'll have to continue trying to find a way to solve not being able to detect Hangul normalize crashes Android some other way. :s