Array index out of bounds

Description

Hello, I am not super well versed in analyzing crash reports. But we are experiencing a fair number of crashes which is being caused from the RNSScreen.m file within this package. I have included the last execution backtrace below which indicates what is happening. Seems like the line: https://github.com/software-mansion/react-native-screens/blob/main/ios/RNSScreen.m#L612

if (currentIndex > 0 && [self.view.reactSubviews[0] isKindOfClass:[RNSScreenStackHeaderConfig class]]) {

is causing the out of bounds index. I am guessing ‘self.view.reactSubviews[0]’ is where the out of bounds index is happening.

Last Exception Backtrace:
0   CoreFoundation                	0x1811390fc __exceptionPreprocess + 220 (NSException.m:200)
1   libobjc.A.dylib               	0x199973d64 objc_exception_throw + 60 (objc-exception.mm:565)
2   CoreFoundation                	0x181242564 _CFThrowFormattedException + 116 (CFObject.m:2072)
3   CoreFoundation                	0x1810d7f00 -[__NSArrayM objectAtIndexedSubscript:] + 188 (NSArrayM.m:309)
4   WeSponsoredApp                	0x1021ea448 -[RNSScreen hideHeaderIfNecessary] + 240 (RNSScreen.m:590)
5   WeSponsoredApp                	0x1021ea2b0 -[RNSScreen viewWillAppear:] + 216 (RNSScreen.m:567)
6   UIKitCore                     	0x1836f3bc8 -[UIViewController _setViewAppearState:isAnimating:] + 664 (UIViewController.m:5522)
7   UIKitCore                     	0x1838233d0 -[UIViewController __viewWillAppear:] + 120 (UIViewController.m:5654)
8   UIKitCore                     	0x1838c265c -[UINavigationController _startCustomTransition:] + 1316 (UINavigationController.m:2082)
9   UIKitCore                     	0x183a20e54 -[UINavigationController _startDeferredTransitionIfNeeded:] + 696 (UINavigationController.m:7519)
10  UIKitCore                     	0x1838f5ea4 -[UINavigationController __viewWillLayoutSubviews] + 168 (UINavigationController.m:7826)
11  UIKitCore                     	0x18381c4a4 -[UILayoutContainerView layoutSubviews] + 228 (UILayoutContainerView.m:88)
12  UIKit                         	0x1f26b0128 -[UILayoutContainerViewAccessibility layoutSubviews] + 52 (UILayoutContainerViewAccessibility.m:132)
13  UIKitCore                     	0x1836d4798 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 2620 (UIView.m:18348)
14  QuartzCore                    	0x184e37138 CA::Layer::layout_if_needed(CA::Transaction*) + 536 (CALayer.mm:10038)
15  QuartzCore                    	0x184e29958 CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 144 (CALayer.mm:2480)
16  QuartzCore                    	0x184e3df80 CA::Context::commit_transaction(CA::Transaction*, double, double*) + 524 (CAContextInternal.mm:2586)
17  QuartzCore                    	0x184e46874 CA::Transaction::commit() + 680 (CATransactionInternal.mm:449)
18  QuartzCore                    	0x184e290bc CA::Transaction::flush_as_runloop_observer(bool) + 100 (CATransactionInternal.mm:941)
19  UIKitCore                     	0x183a8acc0 _UIApplicationFlushCATransaction + 76 (UIApplication.m:0)
20  UIKitCore                     	0x183d255fc _UIUpdateSequenceRun + 84 (_UIUpdateSequence.mm:112)
21  UIKitCore                     	0x1843a15b0 schedulerStepScheduledMainSection + 144 (_UIUpdateCycleScheduler.m:1174)
22  UIKitCore                     	0x1843a0ba0 runloopSourceCallback + 60 (_UIUpdateCycleScheduler.m:1262)
23  CoreFoundation                	0x18115b0d0 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28 (CFRunLoop.c:1972)
24  CoreFoundation                	0x18116bd90 __CFRunLoopDoSource0 + 208 (CFRunLoop.c:2016)
25  CoreFoundation                	0x1810a6098 __CFRunLoopDoSources0 + 268 (CFRunLoop.c:2053)
26  CoreFoundation                	0x1810ab8a4 __CFRunLoopRun + 820 (CFRunLoop.c:2951)
27  CoreFoundation                	0x1810bf468 CFRunLoopRunSpecific + 600 (CFRunLoop.c:3268)
28  GraphicsServices              	0x19cc4a38c GSEventRunModal + 164 (GSEvent.c:2200)
29  UIKitCore                     	0x183a61088 -[UIApplication _run] + 1100 (UIApplication.m:3493)
30  UIKitCore                     	0x1837df958 UIApplicationMain + 2092 (UIApplication.m:5046)
31  WeSponsoredApp                	0x10202feb0 main + 88 (main.m:7)
32  dyld                          	0x10293daa4 start + 520 (dyldMain.cpp:879)

Screenshots

Steps To Reproduce

I am currently trying to reproduce, but am having trouble doing it locally. Looking through our analytics, it seems like it is happening when navigation.goBack() is being called. I will update this ticket if I find anymore details.

Expected behavior

App does not crash

Actual behavior

App crases

Reproduction

I am currently trying to reproduce, but am having trouble doing it locally. Looking through our analytics, it seems like it is happening when navigation.goBack() is being called. I will update this ticket if I find anymore details.

Platform

• iOS
• Android
• Web
• Windows
• tvOS

Workflow

• Managed workflow
• Bare workflow

Package versions

package	version
react-native	0.66.0
@react-navigation/native	^6.0.6
@react-navigation/native-stack	^6.2.5
react-native-screens	^3.8.0
react-native-safe-area-context	^3.3.2
react-native-gesture-handler	^1.10.3
react-native-reanimated	^2.3.0-beta.2
expo	n/a

[cltnschlosser]

I’ve done no investigation yet, but seeing this in a new app release. Version 3.10.1 of react-native-screens. The previous release didn’t have any occurrences of this crash (Also version 3.10.1).

I’ll update here if I find what changed to cause this.

[kkafar]

This should be fixed with changes introduced by me in #1491, as reactSubviews array is now being checked against being empty before accessing the first item.

Notify me if the problem is not solved with latest react-native-screens version.