libswiftCore 崩溃无法重现

Question

我遇到了一个问题，我们的一小部分（少数 %）用户在我们的应用程序上崩溃并出现以下跟踪：

Crashed: com.apple.main-thread
0  libswiftCore.dylib             0x100ae3740 _TTSfq4n_s_n_n_n___TFs17_assertionFailureFTVs12StaticStringSS4fileS_4lineSu5flagsVs6UInt32_Os5Never + 164
1  OMGRedesign                    0x100171f88 specialized DataManager.userLoggingState() -> DataManager.LoggingUserState (DataManager.swift)
2  OMGRedesign                    0x10011e59c specialized APIManager.(login(String, password : String, success : () -> ()?, failure : (Error?) -> ()?) -> ()).(closure #1) (APIManager.swift)
3  OMGRedesign                    0x10012b0d0 partial apply for APIManager.(loginUsingStoredTokens(String, success : () -> ()?, failure : (Error?) -> ()?) -> ()).(closure #1) + 4295897296
4  p2_OAuth2                      0x1008ea38c _TMaC9p2_OAuth210OAuth2Base + 720
5  p2_OAuth2                      0x1008ea1e0 _TMaC9p2_OAuth210OAuth2Base + 292
6  libdispatch.dylib              0x18ebb29a0 _dispatch_client_callout + 16
7  libdispatch.dylib              0x18ebc37a8 _dispatch_barrier_sync_f_slow_invoke + 304
8  libdispatch.dylib              0x18ebb29a0 _dispatch_client_callout + 16
9  libdispatch.dylib              0x18ebb75e8 _dispatch_main_queue_callback_4CF + 996
10 CoreFoundation                 0x18fca90c0 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 12
11 CoreFoundation                 0x18fca6cdc __CFRunLoopRun + 1572
12 CoreFoundation                 0x18fbd6d94 CFRunLoopRunSpecific + 424
13 GraphicsServices               0x191640074 GSEventRunModal + 100
14 UIKit                          0x195e8f130 UIApplicationMain + 208
15 OMGRedesign                    0x1000d3ab8 main (Item.swift:129)
16 libdyld.dylib                  0x18ebe559c start + 4

下面的代码就是这个

func userLoggingState() -> LoggingUserState {

    let userDefault = UserDefaults.standard as UserDefaults

    let isRegularUserLogged = userDefault.bool(forKey:"regular-user-logged")
    let regularUserName = userDefault.string(forKey: "regular-user-username")
    let dummyDefaultUser = userDefault.string(forKey: "default-dummy-user")

    if isRegularUserLogged == false &&
       (regularUserName == nil || regularUserName?.isEmpty == true) &&
       (dummyDefaultUser == nil || dummyDefaultUser?.isEmpty == true) {
        return .None
    }
    else if isRegularUserLogged == true &&
        (regularUserName != nil && regularUserName?.isEmpty == false) &&
        (dummyDefaultUser == nil || dummyDefaultUser?.isEmpty == true) {
        return .Regular
    }
    else if isRegularUserLogged == false &&
        (regularUserName == nil || regularUserName?.isEmpty == true) &&
        (dummyDefaultUser != nil && dummyDefaultUser?.isEmpty == false) {
        return .Dummy
    }
    else {
        PLogWarning("userLogging is in an invalid state, returning None")
        return .None
    }
}

我不明白为什么这会崩溃，因为我无法重现它，所以很难弄清楚。

崩溃报告中的一个非常奇怪的事情是这一行：

15 OMGRedesign                    0x1000d3ab8 main (Item.swift:129)

Item.swift 是一个 CoreData NSManagedObject 派生类。为什么提到那里？

谢谢

Answer 1

事实证明，我们代码中的这个错误是由“fatalError”命令触发的。