React Native Incompatibility: "failed to delete intrinsics.[object Object]syncGenerator%6length"

[EtDu]

When running lockdown.umd.js inside Safari and calling lockdown(), the following error appears:

[Log] Removing intrinsics.%AsyncGenerator%.length
[Error] failed to delete intrinsics.[object Object]syncGenerator%6length
	Console Evaluation (Console Evaluation 1:2063)
	Console Evaluation (Console Evaluation 1:1937)
	Console Evaluation (Console Evaluation 1:2046)
	Console Evaluation (Console Evaluation 1:2074)
	Console Evaluation (Console Evaluation 1:5249)
	Console Evaluation (Console Evaluation 1:5306)
	Console Evaluation (Console Evaluation 2:3)
	evaluateWithScopeExtension
	(anonymous function)
	_wrapCall
< TypeError: Unable to delete property.

[kriskowal]

@erights It looks like there’s a non-standard non-configurable length property on AsyncGenerator. On the one hand, this seems to be a Safari bug, and on the other this is probably safe to allow. Should we retitle this to “Add AsyncGenerator.length to allow-list to accommodate Safari” and do the work?

[erights]

I know I've run SES on Safari before. Is this new? Also, AsyncGenerator is a function. Functions have a length property. I'll investigate. Don't do anything until we understand this.

What version of Safari?

[erights]

To try diagnosing this, I visited https://ses-demo.netlify.app/demos/console/ using Safari Version 14.1 (16611.1.21.161.3) . I found that my old Safari bug came back! I reopened it at

https://bugs.webkit.org/show_bug.cgi?id=222538#c17

After I revise endo to workaround that bug, I'll get back to this one.

[erights]

That one is in progress at #711

[erights]

I cannot reproduce this. While running on my development version of #711 , running a local http server, and visiting http://localhost:8080/demos/console/ I get no errors in the console when I refresh. That demo calls lockdown with no arguments, letting everything default. What lockdown arguments are you using?

[erights]

Revising to

lockdown({
  errorTaming: 'unsafe',
  stackFiltering: 'verbose',
  overrideTaming: 'severe',
});

I was still not able to reproduce. This sets all possibly relevant lockdown options to their non-default setting.

[erights]

@EtDu @kumavis What version of Safari are you using?

[kumavis]

sorry for the safari/react-native confusion

[erights]

@kumavis @EtDu what is the state of this? If it can now be closed, please close it.

[leotm]

apologies for the necropost, appreciate the raising of this issue ^ and prev comments

i'm also looking into this here

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

Revising to

lockdown({
  errorTaming: 'unsafe',
  stackFiltering: 'verbose',
  overrideTaming: 'severe',
});

I was still not able to reproduce. This sets all possibly relevant lockdown options to their non-default setting.

after the revision

undefined is not an object (evaluating '(_console = console)._errorOriginal.apply')
undefined is not an object (evaluating (_console = console)._errorOriginal.apply')

any thoughts appreciated while i continue debugging

edit: if sticking to the original React Native title then imo should remain open till fully resolve and present a solution
nb: it's an error on Android JSC only blocking runtime - not on Android V8 (various warnings), or iOS JSC (Promise warnings)

otherwise if renaming to Add AsyncGenerator.length to allow-list to accommodate Safari i think we can close this from your findings ^

[leotm]

@naugtur and i found the semi-root cause and raised the issue here

• Non-standard ownProperty length on AsyncGenerator and AsyncFunctionPrototype react-native-community/jsc-android-buildscripts#181

[erights]

Ok, with that diagnosis, I agree we should

retitle this to “Add AsyncGenerator.length to allow-list to accommodate Safari” and do the work?

as @kriskowal suggests at #660 (comment)

Thanks @leotm !

Any idea why they do this?

[leotm]

no problemo! makes sense ^ not figured the why yet, but cloned the repo and run the big download (1.12GB) script to see (there's also various patches going on and issues, but none related to the length)