RN 0.66.5 + SES 0.18.1: Error failed to del intrinsics.%AsyncGenerator%.length

Follow-up to
- https://github.com/LavaMoat/docs/issues/11

As seen in
- https://github.com/endojs/endo/issues/660

No error on iOS jsc
- https://github.com/LavaMoat/docs/issues/13

No error on Android v8
- https://github.com/LavaMoat/docs/issues/14

---

```js
lockdown({consoleTaming: 'unsafe'});
```

```console
 WARN  Removing intrinsics.Promise._B
 WARN  Removing intrinsics.Promise._C
 WARN  Removing intrinsics.Promise._D
 WARN  Removing intrinsics.Promise.resolve.prototype
 WARN  Tolerating undeletable intrinsics.Promise.resolve.prototype === undefined
 WARN  Removing intrinsics.Promise.all.prototype
 WARN  Tolerating undeletable intrinsics.Promise.all.prototype === undefined
 WARN  Removing intrinsics.Promise.allSettled.prototype
 WARN  Tolerating undeletable intrinsics.Promise.allSettled.prototype === undefined
 WARN  Removing intrinsics.Promise.reject.prototype
 WARN  Tolerating undeletable intrinsics.Promise.reject.prototype === undefined
 WARN  Removing intrinsics.Promise.race.prototype
 WARN  Tolerating undeletable intrinsics.Promise.race.prototype === undefined
```

```console
 WARN  Removing intrinsics.%AsyncGenerator%.length
 ERROR  failed to delete intrinsics.%AsyncGenerator%.length [TypeError: Unable to delete property.]
 ERROR  TypeError: Unable to delete property.
 ERROR  Invariant Violation: Module AppRegistry is not a registered callable module (calling runApplication). A frequent cause of the error is that the application entry file path is incorrect.
      This can also happen when the JS bundle is corrupt or there is an early initialization error when loading React Native.
```

Android emu: [screenshot](https://user-images.githubusercontent.com/1881059/224106960-d01b7465-4ffa-4865-b7f9-def2ab5a25da.png), then tapping empty white view

```console
 ERROR  Invariant Violation: Module RCTEventEmitter is not a registered callable module (calling receiveTouches). A frequent cause of the error is that the application entry file path is incorrect.
      This can also happen when the JS bundle is corrupt or there is an early initialization error when loading React Native.
```

Bundle: http://localhost:8081/index.bundle?platform=android

es2018.asyncgenerator
https://tc39.es/proposal-async-iteration/#sec-well-known-intrinsic-objects-patch
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/AsyncGenerator
_https://github.com/tc39/proposal-async-iteration#async-generator-functions_

Our AsyncGenerator is defined in our [whitelist.js](https://github.com/endojs/endo/blob/master/packages/ses/src/whitelist.js)

```js
  '%InertAsyncGeneratorFunction%': {
    // Properties of the AsyncGeneratorFunction Constructor
    '[[Proto]]': '%InertFunction%',
    prototype: '%AsyncGenerator%',
  },

  '%AsyncGenerator%': {
    // Properties of the AsyncGeneratorFunction Prototype Object
    '[[Proto]]': '%FunctionPrototype%',
    constructor: '%InertAsyncGeneratorFunction%',
    prototype: '%AsyncGeneratorPrototype%',
    '@@toStringTag': 'string',
  },
```

_More: https://github.com/search?q=repo%3Aendojs%2Fendo%20%25AsyncGenerator%25&type=code_

With methods: `AsyncGenerator.prototype.(next|return|throw)`

**Inheriting prop functions: `Function.prototype.(length|name|prototype)` (error failing to delete <s>these</s> one or more of these props)**

Disabling [`@babel/plugin-proposal-async-generator-functions`](https://babeljs.io/docs/en/babel-plugin-proposal-async-generator-functions) is a red herring, despite being required and pushed in our default preset:

```js
// node_modules/metro-react-native-babel-preset/src/configs/main.js
// ...
  if (isNull || src.indexOf("async") !== -1) {
    extraPlugins.push([
      require("@babel/plugin-proposal-async-generator-functions"),
    ]);
    extraPlugins.push([require("@babel/plugin-transform-async-to-generator")]);
  }
// ...
```

And applying the `return _ref.apply(this, arguments);` (Out) transform
Since disabling it persists the error (and further disabling Babel plugins w/o breaking React Native)

metro-react-native-babel-preset@0.66.2 ❌ (default)
metro-react-native-babel-preset@0.75.1 ❌ (bumped)
_nb: can't bump to 0.76 since this requires Node v16 instead of Node v14 and we're on RN 0.66.5_

"@babel/core": "^7.12.9" ❌ (default)
"@babel/core": "7.21.0" ❌ (bumped)

"@babel/runtime": "^7.12.5" ❌ (default)
"@babel/runtime": "7.21.0" ❌ (bumped)

[metro-react-native-babel-preset](https://github.com/facebook/metro/blob/main/packages/metro-react-native-babel-preset/src/configs/main.js) applies no Android/iOS/jsc/v8-specific transforms (only on Hermes)

**It doesn't appear to be Babel transforming android-jsc differently to iOS jsc and/or android-v8**

Patch `react-native` to use ["jsc-android": "294992.0.0"](https://github.com/react-native-community/jsc-android-buildscripts/releases/tag/v294992.0.0) (WebKitGTK 2.36.3) instead of default ["jsc-android": "^250231.0.0"](https://github.com/facebook/react-native/blob/main/package.json?rgh-link-date=2023-03-01T11%3A58%3A11Z#L134) (WebKitGTK 2.26.1) ❌

<img width="530" alt="Screenshot 2023-03-13 at 13 07 54" src="https://user-images.githubusercontent.com/1881059/224730663-2c31b374-59f0-4dde-9a66-8e0aacc2e61d.png">

Test w/o lockdown

```js
async function* foo() {
  yield await Promise.resolve('a');
  yield await Promise.resolve('b');
  yield await Promise.resolve('c');
}

let str = '';

async function generate() {
  for await (const val of foo()) {
    str = str + val;
  }
  console.log('output', str);
}

generate();

console.log('this', this);
console.log(foo);
console.log('typeof foo:', typeof foo);
console.log('typeof foo.prototype:', typeof foo.prototype);
console.log('length:', foo.length);
console.log('name:', foo.name);
console.log('prototype:', foo.prototype);
console.log(
  'getOwnPropertyDescriptors:',
  Object.getOwnPropertyDescriptors(foo),
);
```

_brave/chrome-v8_

<img width="802" alt="Screenshot 2023-03-13 at 16 44 44" src="https://user-images.githubusercontent.com/1881059/224769088-fbf1f7e7-88d0-4e93-b659-37d73368af12.png">

_RN [v8-android](https://github.com/Kudo/v8-android-buildscripts)_

<img width="732" alt="Screenshot 2023-03-13 at 16 05 56" src="https://user-images.githubusercontent.com/1881059/224759423-1058e2c5-059d-400b-aeb5-96a36aafebe7.png">

**RN [android-jsc](https://github.com/react-native-community/jsc-android-buildscripts)** (not-so-expandable logs output to Metro terminal window)

```console
 LOG  this [Object]
 LOG  [Function foo]
 LOG  typeof foo: function
 LOG  typeof foo.prototype: object
 LOG  foo.length: 0
 LOG  foo.name: foo
 LOG  foo.prototype: {}
 LOG  foo.prototype.constructor: [Function foo]
 LOG  getOwnPropertyDescriptors: {"arguments": {"configurable": false, "enumerable": false, "value": null, "writable": false}, "caller": {"configurable": false, "enumerable": false, "value": null, "writable": false}, "length": {"configurable": true, "enumerable": false, "value": 0, "writable": false}, "name": {"configurable": true, "enumerable": false, "value": "foo", "writable": false}, "prototype": {"configurable": false, "enumerable": false, "value": {}, "writable": true}}
 LOG  output abc
```

**our `%AsyncGenerator%` exists since it works i.e. we have desired output and it's correct**
**our `length` descriptor (inherited prop fn from `Function.prototype`) exists and is [configurable](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty#configurable), so SES should be able to `delete` it during `lockdown`**

`lockdown.umd.js` test (instead of importing `ses`)

<img width="455" alt="Screenshot 2023-03-13 at 15 31 07" src="https://user-images.githubusercontent.com/1881059/224749438-87e80319-f38c-40ae-8fcb-12cccfd8da1e.png">

Result

```console
 WARN  Removing intrinsics.%AsyncFunctionPrototype%.length
 ERROR  failed to delete intrinsics.%AsyncFunctionPrototype%.length [TypeError: Unable to delete property.]
```

But ofc this **isn't** the right path, but we've got another problem 👆 **AsyncFunctionPrototype**

_Delete_ snippet of lockdown below

```js
// ...
try {
  delete obj[prop];
} catch (err) {
  if (prop in obj) {
    if (typeof obj === 'function' && prop === 'prototype') {
      obj.prototype = undefined;
      if (obj.prototype === undefined) {
        // eslint-disable-next-line @endo/no-polymorphic-call
        console.warn(
          `Tolerating undeletable ${subPath} === undefined`,
        );
        // eslint-disable-next-line no-continue
        continue;
      }
    }
    // eslint-disable-next-line @endo/no-polymorphic-call
    console.error(`failed to delete ${subPath}`, err);
  } else {
    // eslint-disable-next-line @endo/no-polymorphic-call
    console.error(`deleting ${subPath} threw`, err);
  }
  throw err;
}
// ...
```

Adding logs

```console
 WARN  Removing intrinsics.%AsyncGenerator%.length
 LOG  {"obj": {}}
 LOG  {"prop": "length"}
 LOG  obj[prop] 0
 ERROR  failed to delete intrinsics.%AsyncGenerator%.length [TypeError: Unable to delete property.]
 ERROR  TypeError: Unable to delete property.
```

**Why when we call `lockdown` with android-jsc (WebKitGTK) our `%AsyncGenerator%` _obj_ doesn't exist (to delete it's props), but it works w/o calling `lockdown` 🤔**

```console
# JSC
 LOG  {"obj": [Function Function]}
 LOG  {"obj": [Function GeneratorFunction]}
 LOG  {"obj": [Function AsyncFunction]}
 LOG  {"obj": [Function AsyncGeneratorFunction]}
 LOG  {"obj": [Function Date]}
 LOG  {"obj": [Function parse]}
 LOG  {"obj": [Function UTC]}
 LOG  {"obj": [Function now]}
 LOG  {"obj": [Function Date]}
 LOG  {"obj": [Function parse]}
 LOG  {"obj": [Function UTC]}
 LOG  {"obj": [Function now]}
 LOG  {"obj": [Function getStackString]}
 LOG  {"obj": [Function Error]}
 LOG  {"obj": [Function get]}
 LOG  {"obj": [Function set]}
 LOG  {"obj": [Function Error]}
 LOG  {"obj": [Function get]}
 LOG  {"obj": [Function set]}
 LOG  {"obj": {}}
 LOG  {"obj": [Function abs]}
 LOG  {"obj": [Function acos]}
# ...
 LOG  {"obj": [Function tanh]}
 LOG  {"obj": [Function trunc]}
 LOG  {"obj": [Function imul]}
 LOG  {"obj": {}}
 LOG  {"obj": [Function abs]}
 LOG  {"obj": [Function acos]}
# ...
 LOG  {"obj": [Function RegExp]}
 LOG  {"obj": [Function get [Symbol.species]]}
 LOG  {"obj": [Function RegExp]}
 LOG  {"obj": [Function get [Symbol.species]]}
 LOG  {"obj": {}}
 LOG  {"obj": [Function next]}
 LOG  {"obj": {}}
```

V8

<img width="839" alt="Screenshot 2023-03-13 at 21 31 05" src="https://user-images.githubusercontent.com/1881059/224837214-4e0ce950-0482-4c50-ac41-9f4144598142.png">

After further debugging, issue raised here
- https://github.com/react-native-community/jsc-android-buildscripts/issues/181

---

```js
lockdown({
  errorTaming: 'unsafe',
  stackFiltering: 'verbose',
  overrideTaming: 'severe',
});
```

No console output in Metro bundler

Android emu: [screenshot](https://user-images.githubusercontent.com/1881059/224114886-3603cae8-b8c3-4ff8-bcd7-4a3b8693b278.png) (OCR'ed to text below)

```console
undefined is not an object (evaluating '(_console = console)._errorOriginal.apply')

undefined is not an object (evaluating (_console = console)._errorOriginal.apply')

reactConsoleErrorHandler@http://localhost:
8081/index.bundle?platform=android&dev=true &minify=false&app=com.rn665&modulesOnly= false&runModule=true:24784:40
http://localhost:8081/index.bundle?platform=
android&dev=true&minify-false&app=com.rn665 &modulesOnly=false&runModule=true:34732:35 native codel
registerError@http://localhost:8081/index.bundle platform=android&dev=true&minify-false&app= com.rn665&modulesOnly=false&runModule=true:
25268:35
http://localhost:8081/index.bundle?platform=
android&dev=true&minify=false&app=com.rn665 &modulesOnly=false&runModule=true:25162:35 levelMethod@http://localhost:8081/index.bundle
?platform=android&dev=true&minify-false&app= com.rn665&modulesOnly=false&runModule=true:
4724:31
reportException@http://localhost:8081/index bundle?platform=android&dev=true&minify= false&app=com.rn665&modulesOnly=false& runModule=true:24733:22 handleException@http://localhost:8081/index bundle?platform=android&dev=true&minify= false&app=com.rn665&modulesOnly=false& runModule=true:24774:22
```

---

Current/only vanilla RN 0.66.5 blocker before metamask-mobile integration


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RN 0.66.5 + SES 0.18.1: Error failed to del intrinsics.%AsyncGenerator%.length #16

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RN 0.66.5 + SES 0.18.1: Error failed to del intrinsics.%AsyncGenerator%.length #16

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