iOS Today Extension Crashing - ios

Question

We've added Today Extension to our app recently.
Its an extension with simple tableView to load data from our server, written in Swift.
But after the extension is online to our users, we've received lots of crash data from Crashlytics and also Apple is reporting same crash issue either.
However, we can't reproduce the crash, or even find the reason of crash, because is crashing on the widgetPerformUpdateWithCompletionHandler method which is called by the system.
Below is the detail of crash log, some information are replaced.
Crashed: com.apple.main-thread
0 MyAppWidget 0x100091d8c MyAppWidgetViewController.(widgetPerformUpdateWithCompletionHandler((NCUpdateResult) -> ()) -> ()).(closure #1) (MyAppWidgetViewController.swift)
1 MyAppKit 0x100603ab4 partial apply for thunk (PostService.swift)
2 MyAppKit 0x100626080 ServiceRequestPerfomer.(performRequest(A, complete : ([B]?, NSError?) -> ()?) -> ()).(closure #1) (ServiceRequestPerformer.swift:35)
3 MyAppKit 0x1006258d4 partial apply for ServiceRequestPerfomer.(performRequest(A, complete : ([B]?, NSError?) -> ()?) -> ()).(closure #1) (ServiceRequestPerformer.swift)
4 MyAppKit 0x100626b34 ServiceRequestPerfomer.((request in _3C50B415180DDC893FFCB75CD7EE7019)(A, complete : (response : Response?, error : NSError?) -> ()?) -> ()).(closure #1) (ServiceRequestPerformer.swift:144)
5 Moya 0x1004b7468 MoyaProvider.(requestNormal(A, queue : OS_dispatch_queue?, progress : (progress : ProgressResponse) -> ()?, completion : (result : Result<Response, Error>) -> ()) -> Cancellable).(closure #1).(closure #1) (Moya.swift:229)
6 Moya 0x1004b8968 MoyaProvider.((sendAlamofireRequest in _1A5616FEE5C423A992964CB19AABD52B)(Request, target : A, queue : OS_dispatch_queue?, progress : (progress : ProgressResponse) -> ()?, completion : (result : Result<Response, Error>) -> ()) -> CancellableToken).(closure #3) (Moya.swift)
7 Moya 0x1004b57b8 partial apply for MoyaProvider.((sendAlamofireRequest in _1A5616FEE5C423A992964CB19AABD52B)(Request, target : A, queue : OS_dispatch_queue?, progress : (progress : ProgressResponse) -> ()?, completion : (result : Result<Response, Error>) -> ()) -> CancellableToken).(closure #3) (Moya.swift)
8 Alamofire 0x1002cff64 Request.(response(queue : OS_dispatch_queue?, completionHandler : (NSURLRequest?, NSHTTPURLResponse?, NSData?, NSError?) -> ()) -> Self).(closure #1).(closure #1) (ResponseSerialization.swift)
9 libdispatch.dylib 0x1819e14bc _dispatch_call_block_and_release + 24
10 libdispatch.dylib 0x1819e147c _dispatch_client_callout + 16
11 libdispatch.dylib 0x1819e6b84 _dispatch_main_queue_callback_4CF + 1844
12 CoreFoundation 0x181f4cd50 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 12
13 CoreFoundation 0x181f4abb8 __CFRunLoopRun + 1628
14 CoreFoundation 0x181e74c50 CFRunLoopRunSpecific + 384
15 GraphicsServices 0x18375c088 GSEventRunModal + 180
16 UIKit 0x18715e088 UIApplicationMain + 204
17 libxpc.dylib 0x181c38ce0 _xpc_objc_main + 784
18 libxpc.dylib 0x181c3a9dc xpc_main + 200
19 Foundation 0x182a57d60 service_connection_handler + 170
20 PlugInKit 0x18929ac48 -[PKService run] + 544
21 PlugInKit 0x18929a8dc +[PKService main] + 56
22 PlugInKit 0x18929ac6c +[PKService _defaultRun:arguments:] + 20
23 libextension.dylib 0x18286a058 NSExtensionMain + 64
24 libdispatch.dylib 0x181a128b8 (Missing)
And the code of widgetPerformUpdateWithCompletionHandler
func widgetPerformUpdateWithCompletionHandler(completionHandler: ((NCUpdateResult) -> Void)) {
// Perform any setup necessary in order to update the view.
// If an error is encountered, use NCUpdateResult.Failed
// If there's no update required, use NCUpdateResult.NoData
// If there's an update, use NCUpdateResult.NewData
let options: [String: AnyObject] = [DCKPostPopularAttributeName : true.stringValue,
DCKPaginationLimitAttributeName : 5]
postService.posts(options: options) { (posts, error) in
let historyPosts = self.userDefaults.arrayForKey(MyAppWidgetViewController.WidgetPostReadIdentifier) as? [UInt]
if let historyPosts = historyPosts {
self.posts = posts!.filter({ (Post) -> Bool in
return !historyPosts.contains(Post.id)
})
} else {
self.posts = posts!
}
self.tableView.reloadData()
self.tableView.hidden = false;
self.loadingLabel?.hidden = true
self.activityIndicator?.stopAnimating()
let contentSize = self.tableView.contentSize
self.preferredContentSize = CGSizeMake(CGRectGetWidth(self.view.frame), contentSize.height);
self.loadMorePostsIfNeeded()
}
completionHandler(NCUpdateResult.NewData)
}
The strange thing is:
We haven't encountered the crash issue while we're using our Today Extension normally (It should show Unable to load if today extension crashes)
We didn't receive any issue from our users reporting that today extension isn't working.
We've found the same crash log on our device, but the today extension is working normally as 1. described. And also, the time of crash log recorded, I'm not using my phone!
So we're guessing it's a 「fake」crash, the crash is logged, but the extension didn't really crashed.
Does anybody facing the same issue?
Thank you!

Answer 1

Answering my own question,
#matt is right, Now I am calling the completionHandler only when data fetch task completes, instead of always call the completionHandler at the last of widgetPerformUpdateWithCompletionHandler method.
I didn't receive crashes anymore, the problem was solved!