expo: Expo Crypto's randomUUID function sometimes returns promises

@tsapeta Hi, we’re on SDK 50 and it’s definitely still occurring. We’ve also found two other bugs in other libraries that exhibit similar issues, which is the expected data isn’t available when it should be on startup (in secure-store and localization).

I might be making a huge presumption, but that’s three expo native modules that exhibit very similar issues. Is it possible there’s an underlying issue in Expo’s native module implementation somewhere? It’s very random to trigger it, which suggests a race condition somewhere to me, but I’m not an expert in the underlying Expo code 😃

While I’ve not tried to figure out the conditions for triggering this bug (or the localization one we’ve also run afoul of), the only way we’re able to trigger the bug in secure-store is when the app is closed, and is opened from cold-start by pressing on a notification alert. And even then, it only happens randomly. Hence it’s really difficult to prepare a minimal reproduction of it!

I am absolutely willing to help track down this issue as it’s become the cause of much hair tearing here. I can submit crash logs wherever possible and test out anything you need me to.

This problem just occurred for me and I’ve been able to reproduce it and trace it using the debugger. The call always returns a promise. I can’t tell what’s going on in the proxy code I’m tracing into, but it ends up here:

[NativeModulesProxy.native.js] NativeProxy[exportedMethodsKey][moduleName].forEach((methodInfo) => { NativeModulesProxy[moduleName][methodInfo.name] = (…args) => { // Use the new proxy to call methods on legacy modules, if possible. if (ExpoNativeProxy?.callMethod) { return ExpoNativeProxy.callMethod(moduleName, methodInfo.name, args); } // Otherwise fall back to the legacy proxy. // This is deprecated and might be removed in SDK47 or later. const { key, argumentsCount } = methodInfo; if (argumentsCount !== args.length) { return Promise.reject(new Error(Native method ${moduleName}.${methodInfo.name} expects ${argumentsCount} ${argumentsCount === 1 ? 'argument' : 'arguments'} but received ${args.length})); } return LegacyNativeProxy.callMethod(moduleName, key, args); }; });

   this calls LegacyNativeProxy.callMethod which ends up here with a "type" of "promise" (which seems wrong).

[NativeModules.js] function genMethod(moduleID: number, methodID: number, type: MethodType) { let fn = null; if (type === ‘promise’) { fn = function promiseMethodWrapper(…args: Array<mixed>) { // In case we reject, capture a useful stack trace here. /* $FlowFixMe[class-object-subtyping] added when improving typing for * this parameters */ const enqueueingFrameError: ExtendedError = new Error(); return new Promise((resolve, reject) => { BatchedBridge.enqueueNativeCall( moduleID, methodID, args, data => resolve(data), errorData => reject( updateErrorWithErrorData( (errorData: $FlowFixMe), enqueueingFrameError, ), ), );

    It seems like the JS wrappers for the native code have decided that the return value is a promise (for whatever reason). I don't know if this helps, but thought I'd pass it along.

Thanks for all the details @Braden1996 – we’ve been seeing this mentioned several times but without any details that helped to narrow it down (till now!).

I’ll also try to reproduce this – it’s the only closure in the module, so perhaps this has something to do with it?

@martinezleoml Could you try on SDK 50? My PR that autoclosed this issue landed in SDK 50.

We’re planning to upgrade to SDK 50 in the coming weeks, I’ll keep you posted. But as mentioned by @skdrew, the issue occurs very randomly.

Btw thanks for re-opening the issue. 😃

If you’re looking for a relatively easy fix in the meantime, try migrate away from expo-crypto to react-native-get-random-values. It worked for us at the time! Although we’re now on SDK 50 and are using expo-crypto perfectly fine.

@martinezleoml Could you try on SDK 50? My PR that autoclosed this issue landed in SDK 50.

We’re planning to upgrade to SDK 50 in the coming weeks, I’ll keep you posted. But as mentioned by @skdrew, the issue occurs very randomly.

Btw thanks for re-opening the issue. 😃

@martinezleoml Could you try on SDK 50? My PR that autoclosed this issue landed in SDK 50.

Thought I’d add an extra comment here - this issue was causing our production app to have a serious error that has resulted in a large number of negative reviews on the app store. In order to work around it we’ve replaced expo-crypto with react-native-get-random-values and uuid.

This issue is not resolved. It should be re-opened until it’s been confirmed to be fixed.

Had the same issue while upgrading to Expo 48.

• expo: 48.0.20
• expo-crypto: 12.2.1

It is very difficult to reproduce, and when it happens, just restarting the application to get it working again.