由于从 -traitCollection 返回的 nil，应用程序在 iOS 13 上崩溃，这是不允许的

Question

我正在处理来自 archived repo 的 Telegram 源代码，并且应用程序在每个 ViewController 中崩溃，我可以看到以下错误。我还尝试注释掉一些代码，但崩溃只是从一个类转移到另一个类。有什么方法可以阻止traitCollection 导致这些崩溃？

Telegram[50090:787790] *** Assertion failure in UITraitCollection * _Nonnull _UIGetCurrentFallbackTraitCollection(void)(), /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKitCore_Sim/UIKit-3899.13.13/_UIFallbackEnvironment.m:91
Telegram[50090:787790] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '<Decorated498f14ad: 0x7f80e9d46b20; baseClass = UIImageView; frame = (0 0; 8 14); userInteractionEnabled = NO; layer = <CALayer: 0x6000023abc00>> returned nil from -traitCollection, which is not allowed.'

PS：我无法切换到较新版本的 Telegram iOS。

我试过this answer，但没有帮助

我还尝试使用异步调度程序运行我的代码行，但仍然没有变化

First throw call stack:
(
0   CoreFoundation                      0x00007fff23b98bde __exceptionPreprocess + 350
1   libobjc.A.dylib                     0x00007fff503b5b20 objc_exception_throw + 48
2   CoreFoundation                      0x00007fff23b98958 +[NSException raise:format:arguments:] + 88
3   Foundation                          0x00007fff255eb7be -[NSAssertionHandler handleFailureInFunction:file:lineNumber:description:] + 166
4   UIKitCore                           0x00007fff46dd08bd _UIGetCurrentFallbackTraitCollection + 962
5   UIKitCore                           0x00007fff46dce21a +[UITraitCollection _currentTraitCollection] + 196
6   UIKitCore                           0x00007fff476366c6 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 2386
7   QuartzCore                          0x00007fff2b030ef9 -[CALayer layoutSublayers] + 255
8   QuartzCore                          0x00007fff2b0358ff _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 517
9   QuartzCore                          0x00007fff2b041fe4 _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 80
10  QuartzCore                          0x00007fff2af8a4a8 _ZN2CA7Context18commit_transactionEPNS_11TransactionEd + 324
11  QuartzCore                          0x00007fff2afbfab3 _ZN2CA11Transaction6commitEv + 643
12  UIKitCore                           0x00007fff4715c27c _UIApplicationFlushRunLoopCATransactionIfTooLate + 104
13  UIKitCore                           0x00007fff471fd878 __handleEventQueueInternal + 6902
14  CoreFoundation                      0x00007fff23afbac1 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
15  CoreFoundation                      0x00007fff23afb9ec __CFRunLoopDoSource0 + 76
16  CoreFoundation                      0x00007fff23afb1c4 __CFRunLoopDoSources0 + 180
17  CoreFoundation                      0x00007fff23af5ecf __CFRunLoopRun + 1263
18  CoreFoundation                      0x00007fff23af56b6 CFRunLoopRunSpecific + 438
19  GraphicsServices                    0x00007fff3815cbb0 GSEventRunModal + 65
20  UIKitCore                           0x00007fff47162a67 UIApplicationMain + 1621
21  Telegram                            0x000000010bcbb0f4 main + 132
22  libdyld.dylib                       0x00007fff5123bcf5 start + 1
)

Answer 1

如果是旧的 Telegram 源代码，TGSimpleImageView 会导致这个问题，只需在 traitCollection 函数中放入以下代码而不是 'return nil'

- (UITraitCollection *)traitCollection
{
    if (@available(iOS 13.0, *)) {
        [UITraitCollection setCurrentTraitCollection:[[UITraitCollection alloc]init]];
    } else {
        // Fallback on earlier versions
    };
    return [[UITraitCollection alloc]init];
}