[Bug]: Crash due to WKWebView deallocation from a background thread

[nalexn]

Are you seeing the problem on Android or iOS?

iOS

Contact Details

Describe the bug

Crash

Site Key

No response

Select the method used to integrate with reCAPTCHA Mobile.

SPM (iOS)

SDK Version

18.4.0

To Reproduce

We don't know the exact steps that lead to a crash.

Expected behavior

The SDK should not crash the host app.

Development IDE

Xcode 15.2

To Reproduce

It happened on a variety of phone models and OS versions, there is no pattern.

Relevant log output

The crash report refers to obfuscated class and method names, specifically `mAyzaYEh` class and `mAyzaYEh.szjxzvtp(withvwqnhbxp:withTimeout:completionHandler:)` method.

How do we know it's Recaptcha's class? We looked it up in Obj-C runtime, `mAyzaYEh` is defined in RecaptchaEnterprise framework.

A portion of the crash report with the essential info:

NSInternalInconsistencyException: Modifications to the layout engine must not be performed from a background thread after it has been accessed from the main thread.

0  CoreFoundation +0xec698         ___exceptionPreprocess
1  libobjc.A.dylib +0x2bc7c        _objc_exception_throw
2  CoreAutoLayout +0x56c4          __AssertAutoLayoutOnAllowedThreadsOnly
3  CoreAutoLayout +0xa4e0          -[NSISEngine withBehaviors:performModifications:]
4  UIKitCore +0x10dd8              -[UIView _postMovedFromSuperview:]
5  UIKitCore +0x7f6f0              ___UIViewWasRemovedFromSuperview
6  UIKitCore +0x7ee6c              -[UIView(Hierarchy) removeFromSuperview]
7  WebKit +0x47bbd4                -[WKWebView(WKViewInternalIOS) removeFromSuperview]
8  PCoreServices +0x919abc         @objc mAyzaYEh.__deallocating_deinit
9  PCoreServices +0x91437c         type metadata accessor for NSKeyedUnarchiver
10 libswiftCore.dylib +0x3a6910    __swift_release_dealloc
11 libswiftCore.dylib +0x3a7fac    bool swift::RefCounts<swift::RefCountBitsT<(swift::RefCountInlinedness)1> >::doDecrementSlow<(swift::PerformDeinit)1>(swift::RefCountBitsT<(swift::RefCountInlinedness)1>, unsigned int)
12 PCoreServices +0x9133ac         partial apply for implicit closure #2 in implicit closure #1 in mAyzaYEh.szjxzvtp(withvwqnhbxp:withTimeout:completionHandler:)
13 libswiftCore.dylib +0x3a6910    __swift_release_dealloc

### Relevant log output

_No response_

[mcorner]

Are you using uikit and objc? We think we might know what the issue is (relatively easy fix).

[nalexn]

It's mostly UIKit, and Swift

[mcorner]

Ok. We have a probable fix. Will be in the next release.

[jesusnieto1983]

Do you know when will be the next release that include this fix? Thanks in advance

[walterjgsp]

@jesusnieto1983. A patch with a potential fix for this bug is scheduled for release next week..

[haojin2020]

The same issue was noticed in sdk 18.4.0 in our app, it created a spike in our crash data. Looking forward to the next release.

[walterjgsp]

@haojin2020 and @jesusnieto1983, a patch was released yesterday. Could you please test and confirm if it has solved your issue?

[nalexn]

18.4.1 fixes the issue, thanks