iOS CALayer [CALayer(CALayerPrivate) ancestorSharedWithLayer:] 新风作浪 2022-08-31 2024-01-14 [CALayer(CALayerPrivate) ancestorSharedWithLayer:] 错误日志：
Crashed: com.apple.main-thread 0 QuartzCore 0x23790 CA::Layer::superlayer(CA::Transaction*) + 28 1 QuartzCore 0xad748 -[CALayer(CALayerPrivate) ancestorSharedWithLayer:] + 112 2 QuartzCore 0x1d010 CA::Layer::map_geometry(CALayer*, CALayer*, void (*)(void*, CA::Mat4<double> const&), void (*)(void*, CA::Mat4<double> const&), void*) + 136 3 QuartzCore 0xc9c94 -[CALayer convertPoint:toLayer:] + 80 4 UIKitCore 0x234cd4 -[UIView(Geometry) convertPoint:toView:] + 112 5 UIAccessibility 0x1b960 -[NSObject(AXPrivCategory) _accessibilityBaseHitTest:withEvent:] + 3416 6 UIKit 0xce494 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 160 7 UIKit 0xa4318 -[UITableViewCellAccessibility _accessibilityHitTest:withEvent:] + 2280 8 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 9 UIKit 0x96cc0 -[UITableViewAccessibility _accessibilityHitTest:withEvent:] + 164 10 PreferencesFramework 0xb6fc (缺少 UUID a69f299d65e639d69a322e24499981e1) 11 UIAccessibility 0x1bd68 __64-[NSObject(AXPrivCategory) _accessibilityBaseHitTest:withEvent:]_block_invoke.274 + 112 12 UIAccessibility 0x1b514 -[NSObject(AXPrivCategory) _accessibilityBaseHitTest:withEvent:] + 2316 13 UIKit 0xce494 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 160 14 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 15 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 16 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 17 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 18 UIKit 0x3f1d4 -[UICollectionViewCellAccessibility _accessibilityHitTest:withEvent:] + 120 19 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 20 UIKit 0x3ae38 -[UICollectionViewAccessibility _accessibilityHitTest:withEvent:] + 228 21 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 22 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 23 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 24 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 25 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 26 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 27 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 28 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 29 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 30 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 31 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 32 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 33 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 34 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 35 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 36 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 37 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 38 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 39 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 40 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 41 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 42 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 43 UIKit 0xccc88 -[UIViewAccessibility __accessibilityHitTest:withEvent:] + 1604 44 UIKit 0xce464 -[UIViewAccessibility _accessibilityHitTest:withEvent:] + 112 45 UIKit 0xd6590 -[UIWindowAccessibility _accessibilityHitTest:withEvent:] + 144 46 UIAccessibility 0x628c _copyElementAtPositionCallback + 1952 47 AXRuntime 0xc7f4 ___AXXMIGCopyElementAtPosition_block_invoke + 72 48 AXRuntime 0xb680 _handleNonMainThreadCallback + 72 49 AXRuntime 0xc67c _AXXMIGCopyElementAtPosition + 268 50 AXRuntime 0x7f48 _AXUIElementCopyElementAtPositionWithParams + 2648 51 UIAccessibility 0x24b44 -[NSObject(AXPrivCategory) _accessibilityVisiblePointHitTestingAnyElement:] + 2852 52 UIAccessibility 0x25020 -[NSObject(AXPrivCategory) _accessibilityIsVisibleByCompleteHitTest:] + 196 53 UIAccessibility 0x30010 -[NSObject(AXPrivCategory) _iosAccessibilityAttributeValue:] + 10488
这个Bug由来已久，崩溃日志每个版本都会有一两个用户，复现好久都没复现出来，看日志信息也不知道咋解决。唯一搜索到相关的是这个 https://www.cocoanetics.com/2013/11/radar-accessibility-based-tools-crash-app-running-in-ios-7-simulator/ ，因为项目中使用DTCoreText ，猜测肯定是自定义View然后丢给 DTCoreText 上渲染引起的。终于捉到一个用户反馈，发来视频，几乎一样的环境系统没发现出来问题，最在无可奈何的时候发现状态栏是昂有个蓝色的话筒，经过一番查找资料，这是iOS系统的辅助功能“语音控制”。
然后在系统 设置 –> 辅助功能 –> 语音控制 –> 关闭 时，发现不崩了。
当时也没找到问题所在价加上着急发版，又有很多需求，只让用户关闭语音控制功能。时隔两三年又来用户反馈，缺怎么越记不起怎么操作的，记忆里在衰退了。
后台经过二分法注释代码，发现是自定义的一个 View 上 add 了一个 textField。isAccessibilityElement 默认打开，关闭这个属性即可。
self.textField = [[UITextField alloc] init]; self.textField.isAccessibilityElement = NO;
这里面涉及无障碍框架 UIAccessibility。
又发现新的问题，虽然设置了 view.isAccessibilityElement = NO; 但是在 iOS 16 上又闪退了。
作者给到回复是
I found that this comes from iOS seemingly having a problem with NSProxy. That’s being used to have a stand-in for a custom text attachment view that might be not created yet. It can also be worked around by omitting such a proxy for all text attachments.
Anybody have a custom view that implements accessibility?
So for the time being - until we know better - I’ve just replaced the NSProxy with NSObject. With that the crash doesn’t occur.
大概意思是 NSProxy 引起的，用NSObject替代NSProxy。 但是测试后发现还是有问题。既然没用到 Accessibility 相关方法，就删除了。
fork 了源码，移除了 DTAccessibilityViewProxyDelegate 相关代理事件 https://github.com/duxinfeng/DTCoreText/commit/ebd552e7ac4152f28b62722a71e55b567dbb1ec9
参考链接：
1、https://www.jianshu.com/p/0991a4f0bc0c
2、https://developer.apple.com/documentation/objectivec/nsobject/1615141-isaccessibilityelement?language=objc
3、https://github.com/Cocoanetics/DTCoreText/issues/1272
