Swift 3中的Date._unconditionallyBridgeFromObjectiveC（NSDate？）崩溃 [英] Date._unconditionallyBridgeFromObjectiveC(NSDate?) crash in Swift 3

问题描述

我在一个快速文件中具有以下功能。我是从Obj C文件中使用NSDate代替startDate来调用的。而且很多时候，不是每次，我的应用都会崩溃

I have following function in a swift file. I am calling this from Obj C file with NSDate in place of startDate. And quite often, not every time, my app crashes with

Date._unconditionallyBridgeFromObjectiveC（NSDate？）

Date._unconditionallyBridgeFromObjectiveC(NSDate?)

我该如何解决？

func trackMeetingEnded(_ name: String, startDate: Date, backgroundTime: TimeInterval) {}

堆栈跟踪

Crashed: com.apple.main-thread
0  libswiftFoundation.dylib       0x102061e98 static Date._unconditionallyBridgeFromObjectiveC(NSDate?) -> Date + 72
1  Acid                           0x10017ece4 @objc static ClusteredMixpanel.trackMeetingEnded(String, startDate : Date, backgroundTime : Double) -> () (MixpanelMeeting.swift)
2  Acid                           0x10073e1bc __56-[MeetingLifeCycleViewController stateInitialization]_block_invoke.221 (MeetingLifeCycleViewController.m:267)
3  Acid                           0x1001ee5c4 partial apply for thunk (StateMachine.swift)
4  Acid                           0x1001ea70c specialized State.willLeaveState(State) -> () (StateMachine.swift:238)
5  Acid                           0x1001ead90 specialized StateMachine.transitionToState(State) -> Bool (StateMachine.swift)
6  Acid                           0x1001e1f18 @objc StateMachine.transitionToState(State) -> Bool (StateMachine.swift)
7  Acid                           0x10073ace0 -[MeetingLifeCycleViewController dismissCall] (MeetingLifeCycleViewController.m:538)
8  Acid                           0x10086d648 -[InMeetingViewController hangup] (InMeetingViewController.m:531)

在这种情况下，我相信NSDate到Date的转换是由OS完成的。仅在迁移到Swift 3之后才能看到该问题。是否存在任何已知问题？我在网上找不到任何东西：（

I believe NSDate to Date conversion is done by OS in this case. The issue is seen only after migration to Swift 3. Are there any known issues around this? I could not find anything online :(

推荐答案

您可能需要仔细检查 NSDate 实际上不是- nil ，因为没有什么东西可以像Swift一样有效地强制Obj-C方面

You probably need to double check that the NSDate coming from Objective-C is actually non-nil, since there's nothing that's actively enforcing that on the Obj-C side the way there is on the Swift side.

我最终将尽可能多的 Date 转换为 Date？ s就像我从Obj-C处被叫到一样，然后进行了很多后卫检查检查。

I wound up converting as many Dates to Date?s as I could find being called from Obj-C, then doing a whole lot of guard let checks.

在开发过程中，您还可以抛出 assertionFailure 对您大喊大叫，以了解那些 nil 的位置您不期望的日期来自。例如：

You can also throw in an assertionFailure to yell at you when you're in development about where those nil dates you're not expecting are coming from. For example:

guard let date = passedInDate else {
    assertionFailure("Turns out the passed-in date was nil!")
    return 
}

然后查看一下堆栈跟踪，当它被击中时，是否可以更好地了解为什么在那里获得意外的 nil 值。

Then take a look at your stack trace when that gets hit to see if you can get a better grip on why you're getting an unexpected nil value there.

更新：这是在Swift源代码中发生崩溃的位置。

Update: Here's where the crash is occurring in the Swift source code.

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