Develop Reference

Error when trying to test Swift - PFObject using Quick

I need to write some quick test for a Swift-PFObject (using Subclassing), my class:
class Category: PFObject, PFSubclassing {
#NSManaged var name : String!
#NSManaged var detail : String!
#NSManaged var iconUrl : String!
#NSManaged var imageUrl: String!
#NSManaged var people : PFRelation!
override class func initialize() {
var onceToken : dispatch_once_t = 0;
dispatch_once(&onceToken) {
self.registerSubclass()
}
}
class func parseClassName() -> String {
return "Category"
}
}
My Test implementation (not completed yet) :
class CategorySpec: QuickSpec {
override func spec() {
var category = Category()
.
.
.
}
}
I've checked the 'Target Membership' for Tests in Category class: (not using public keyword in my class and methods).
This is the stack trace when run the test:
2015-08-04 23:52:07.314 SnipMe[14216:127914] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Tried to register both SnipMe.Category and SnipMeTests.Category as the native PFObject subclass of Category. Cannot determine the right class to use because neither inherits from the other.'
*** First throw call stack:
(
0 CoreFoundation 0x000000010fa64c65 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x000000010feffbb7 objc_exception_throw + 45
2 CoreFoundation 0x000000010fa64b9d +[NSException raise:format:] + 205
3 Parse 0x000000010e0d9a67 +[PFObject registerSubclass] + 536
4 SnipMeTests 0x000000011c6b77ef _TFZFC11SnipMeTests8Category10initializeFMS0_FT_T_U_FT_T_ + 63
5 SnipMeTests 0x000000011c6b7187 _TTRXFo__dT__XFdCb__dT__ + 39
6 libdispatch.dylib 0x0000000111360964 _dispatch_client_callout + 8
7 libdispatch.dylib 0x000000011134e902 dispatch_once_f + 129
8 SnipMeTests 0x000000011c6b727a _TZFC11SnipMeTests8Category10initializefMS0_FT_T_ + 234
9 SnipMeTests 0x000000011c6b7359 _TToZFC11SnipMeTests8Category10initializefMS0_FT_T_ + 25
10 libobjc.A.dylib 0x000000010ff004d6 _class_initialize + 648
11 libobjc.A.dylib 0x000000010ff096e1 lookUpImpOrForward + 351
12 libobjc.A.dylib 0x000000010ff160d3 objc_msgSend + 211
13 SnipMeTests 0x000000011c6b7437 _TMaC11SnipMeTests8Category + 39
14 SnipMeTests 0x000000011c6b4d88 _TFC11SnipMeTests12CategorySpec4specfS0_FT_T_ + 24
15 SnipMeTests 0x000000011c6b4eb2 _TToFC11SnipMeTests12CategorySpec4specfS0_FT_T_ + 34
16 Quick 0x000000011c7e673a +[QuickSpec initialize] + 202
17 libobjc.A.dylib 0x000000010ff004d6 _class_initialize + 648
18 libobjc.A.dylib 0x000000010ff096e1 lookUpImpOrForward + 351
19 libobjc.A.dylib 0x000000010ff160d3 objc_msgSend + 211
20 CoreFoundation 0x000000010f9999ad -[__NSSetM member:] + 77
21 CoreFoundation 0x000000010f987da6 -[NSSet containsObject:] + 22
22 XCTest 0x000000011c6d975a +[XCTestCase(RuntimeUtilities) allSubclasses] + 159
23 XCTest 0x000000011c6cc59c +[XCTestSuite _suiteForBundleCache] + 183
24 XCTest 0x000000011c6cc777 +[XCTestSuite suiteForBundleCache] + 34
25 XCTest 0x000000011c6ccb0a +[XCTestSuite allTests] + 56
26 XCTest 0x000000011c6da83a __33+[XCTestProbe specifiedTestSuite]_block_invoke + 87
27 libdispatch.dylib 0x0000000111360964 _dispatch_client_callout + 8
28 libdispatch.dylib 0x000000011134e902 dispatch_once_f + 129
29 XCTest 0x000000011c6da7e1 +[XCTestProbe specifiedTestSuite] + 98
30 XCTest 0x000000011c6daada +[XCTestProbe runTests:] + 112
31 Foundation 0x000000010d9d61e5 __NSFireDelayedPerform + 387
32 CoreFoundation 0x000000010f9cc174 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 20
33 CoreFoundation 0x000000010f9cbd35 __CFRunLoopDoTimer + 1045
34 CoreFoundation 0x000000010f98dd3d __CFRunLoopRun + 1901
35 CoreFoundation 0x000000010f98d366 CFRunLoopRunSpecific + 470
36 GraphicsServices 0x0000000113027a3e GSEventRunModal + 161
37 UIKit 0x000000010e4b98c0 UIApplicationMain + 1282
38 SnipMe 0x000000010d4e7f67 main + 135
39 libdyld.dylib 0x0000000111391145 start + 1
40 ??? 0x000000000000000a 0x0 + 10
)
libc++abi.dylib: terminating with uncaught exception of type NSException
Any ideas please? thanks in advance.

app crash when using multiple inout param in function

My application crash when i use below code.
var char : Character = "1"
var char2 : Character = "1"
func changeChar( char1: inout Character,char2: inout Character) {
char = "b"
char2 = "b"
}
override func viewDidAppear(_ animated: Bool) {
print(char,char2)
changeChar(char1: &char, char2: &char2)
print(char,char2)
}
Error:
Simultaneous accesses to 0x100e0ec50, but modification requires exclusive access.
Previous access (a modification) started at PPlayerNew`ViewController.viewDidAppear(_:) + 340 (0x1000eeda8).
Current access (a modification) started at:
0 libswiftCore.dylib 0x00000001004b9a38 swift_beginAccess + 468
1 PPlayerNew 0x00000001000ee960 ViewController.char.setter + 92
2 PPlayerNew 0x00000001000eebbc ViewController.changeChar(char1:char2:) + 96
3 PPlayerNew 0x00000001000eec54 ViewController.viewDidAppear(_:) + 436
4 PPlayerNew 0x00000001000eef98 #objc ViewController.viewDidAppear(_:) + 64
5 UIKit 0x000000018b3cc5c0 <redacted> + 856
6 UIKit 0x000000018b439630 <redacted> + 44
7 UIKit 0x000000018b43959c <redacted> + 92
8 UIKit 0x000000018b641470 <redacted> + 556
9 UIKit 0x000000018b633420 <redacted> + 528
10 UIKit 0x000000018b64c7b4 <redacted> + 152
11 CoreFoundation 0x00000001852312f8 <redacted> + 20
12 CoreFoundation 0x0000000185230a08 <redacted> + 288
13 CoreFoundation 0x000000018522e6c0 <redacted> + 728
14 CoreFoundation 0x000000018515ebfc CFRunLoopRunSpecific + 424
15 GraphicsServices 0x0000000186bc9010 GSEventRunModal + 100
16 UIKit 0x000000018b419bcc UIApplicationMain + 208
17 PPlayerNew 0x00000001000f0570 main + 76
18 libdyld.dylib 0x000000018416d598 <redacted> + 4
But when i use single param function, like below. code is working
func changeChar( char1: inout Character) {
char = "b"
}
So my main goal is to use inout function with multiple parameters.How can i do this or what's wrong with my code?
Thank You.

You’re changing the property char in your func instead of the parameter char1.

Determining crash on HKObject _validateForCreation

While testing on device (Apple Watch) attempting to save an HKWorkout into HealthKit I am adding samples of distance samples, calories, heart rates and vo2Max to the workout. Unfortunately unlike this question I am not getting as detailed as a trace back...as far as I can tell it's crashing on adding a sample but I can't tell which sample it is or why?
Code:
private func addSamples(toWorkout workout: HKWorkout, from startDate: Date, to endDate: Date, handler: #escaping (Bool, Error?) -> Void) {
let vo2MaxSample = HKQuantitySample(type: HKQuantityType.quantityType(forIdentifier: HKQuantityTypeIdentifier.vo2Max)!, quantity: vo2MaxQuantity(), start: startDate, end: endDate)
var samples = [HKQuantitySample]()
for distanceWalkingRunningSample in distanceWalkingRunningSamples {
samples.append(distanceWalkingRunningSample)
}
for energySample in energySamples {
samples.append(energySample)
}
samples.append(vo2MaxSample)
samples.append(contentsOf: heartRateValues)
// Add samples to workout
healthStore.add(samples, to: workout) { (success: Bool, error: Error?) in
if error != nil {
print("Adding workout subsamples failed with error: \(String(describing: error))")
handler(false, error)
}
if success {
print("Success, samples have been added, workout Saved.") //WorkoutStartDate = \(workout.startDate) WorkoutEndDate = \(workout.endDate)
handler(true, nil)
} else {
print("Adding workout subsamples failed no error reported")
handler(false, nil)
}
}
}
Trace:
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
Triggered by Thread: 0
Application Specific Information:
abort() called
Filtered syslog:
None found
Last Exception Backtrace:
0 CoreFoundation 0x1bdf75e8 __exceptionPreprocess + 124
1 libobjc.A.dylib 0x1b15717c objc_exception_throw + 33
2 CoreFoundation 0x1bdf752c +[NSException raise:format:] + 103
3 HealthKit 0x273dbdde -[HKObject _validateForCreation] + 111
4 HealthKit 0x273dbc48 +[HKObject _newDataObjectWithMetadata:device:config:] + 219
5 HealthKit 0x273dbb30 +[HKSample _newSampleWithType:startDate:endDate:device:metadata:config:] + 159
6 HealthKit 0x273e9ba8 +[HKWorkout _workoutWithActivityType:startDate:endDate:workoutEvents:duration:totalActiveEnergyBurned:totalBasalEnergyBurned:totalDistance:totalSwimmingStrokeCount:totalFlightsClimbed:goalType:goal:device:metadata:config:] + 431
7 HealthKit 0x274a9342 +[HKWorkout workoutWithActivityType:startDate:endDate:workoutEvents:totalEnergyBurned:totalDistance:device:metadata:] + 109
8 HealthKit 0x274a9160 +[HKWorkout workoutWithActivityType:startDate:endDate:workoutEvents:totalEnergyBurned:totalDistance:metadata:] + 87
9 Watch Extension 0x002b7ecc 0x290000 + 163532
10 Watch Extension 0x002b79fc 0x290000 + 162300
11 Watch Extension 0x002bb7ac 0x290000 + 178092
12 Watch Extension 0x002ab9e8 0x290000 + 113128
13 Watch Extension 0x002a9660 0x290000 + 104032
14 Watch Extension 0x002a8f68 0x290000 + 102248
15 Watch Extension 0x002a7748 0x290000 + 96072
16 libdispatch.dylib 0x1b8875ec _dispatch_call_block_and_release + 5
17 libdispatch.dylib 0x1b8875c8 _dispatch_client_callout + 1
18 libdispatch.dylib 0x1b897822 _dispatch_main_queue_callback_4CF$VARIANT$mp + 853
19 CoreFoundation 0x1bdb31ac __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 5
20 CoreFoundation 0x1bdb0f42 __CFRunLoopRun + 929
21 CoreFoundation 0x1bcfe96a CFRunLoopRunSpecific + 349
22 GraphicsServices 0x1d8beb92 GSEventRunModal + 89
23 UIKit 0x21f556da UIApplicationMain + 151
24 libxpc.dylib 0x1bb2fd78 _xpc_objc_main + 581
25 libxpc.dylib 0x1bb31720 xpc_main + 149
26 Foundation 0x1c7bbf24 -[NSXPCListener resume] + 175
27 PlugInKit 0x22ccbf40 -[PKService run] + 709
28 WatchKit 0x2b5777b8 main + 157
29 libdyld.dylib 0x1b8e2b8e 0x1b8df000 + 15246
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0 libsystem_kernel.dylib 0x1b9e443c __pthread_kill + 8
1 libsystem_pthread.dylib 0x1baec270 pthread_kill$VARIANT$mp + 334
2 libsystem_c.dylib 0x1b96d28e abort + 106
3 libc++abi.dylib 0x1b136cfe __cxa_bad_cast + 0
4 libc++abi.dylib 0x1b136e8a default_unexpected_handler+ 16010 () + 0
5 libobjc.A.dylib 0x1b1573e0 _objc_terminate+ 29664 () + 102
6 libc++abi.dylib 0x1b1493fc std::__terminate(void (*)+ 91132 ()) + 6
7 libc++abi.dylib 0x1b148ed6 __cxxabiv1::exception_cleanup_func+ 89814 (_Unwind_Reason_Code, _Unwind_Exception*) + 0
8 libobjc.A.dylib 0x1b157274 _objc_exception_destructor+ 29300 (void*) + 0
9 CoreFoundation 0x1bdf7530 -[NSException initWithCoder:] + 0
10 HealthKit 0x273dbde2 -[HKObject _validateForCreation] + 116
11 HealthKit 0x273dbc4c +[HKObject _newDataObjectWithMetadata:device:config:] + 224
12 HealthKit 0x273dbb34 +[HKSample _newSampleWithType:startDate:endDate:device:metadata:config:] + 164
13 HealthKit 0x273e9bac +[HKWorkout _workoutWithActivityType:startDate:endDate:workoutEvents:duration:totalActiveEnergyBurned:totalBasalEnergyBurned:totalDistance:totalSwimmingStrokeCount:totalFlightsClimbed:goalType:goal:device:metadata:config:] + 436
14 HealthKit 0x274a9346 +[HKWorkout workoutWithActivityType:startDate:endDate:workoutEvents:totalEnergyBurned:totalDistance:device:metadata:] + 114
15 HealthKit 0x274a9164 +[HKWorkout workoutWithActivityType:startDate:endDate:workoutEvents:totalEnergyBurned:totalDistance:metadata:] + 92
16 Watch Extension 0x002b7ed0 0x290000 + 163536
17 Watch Extension 0x002b7a00 0x290000 + 162304
18 Watch Extension 0x002bb7b0 0x290000 + 178096
19 Watch Extension 0x002ab9ec 0x290000 + 113132
20 Watch Extension 0x002a9664 0x290000 + 104036
21 Watch Extension 0x002a8f6c 0x290000 + 102252
22 Watch Extension 0x002a774c 0x290000 + 96076
23 libdispatch.dylib 0x1b8875f0 _dispatch_call_block_and_release + 10
24 libdispatch.dylib 0x1b8875cc _dispatch_client_callout + 6
25 libdispatch.dylib 0x1b897826 _dispatch_main_queue_callback_4CF$VARIANT$mp + 858
26 CoreFoundation 0x1bdb31b0 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 10
27 CoreFoundation 0x1bdb0f46 __CFRunLoopRun + 934
28 CoreFoundation 0x1bcfe96e CFRunLoopRunSpecific + 354
29 GraphicsServices 0x1d8beb96 GSEventRunModal + 94
30 UIKit 0x21f556de UIApplicationMain + 156
31 libxpc.dylib 0x1bb2fd7c _xpc_objc_main + 586
32 libxpc.dylib 0x1bb31724 xpc_main + 154
33 Foundation 0x1c7bbf28 service_connection_handler + 0
34 PlugInKit 0x22ccbf44 -[PKService run] + 714
35 WatchKit 0x2b5777bc main + 162
36 libdyld.dylib 0x1b8e2b92 start + 2

Crash when opening FMDB in background mode

I have my Cordova app on iOS starting up from a significant location change, and sometimes when it starts this way, it crashes while opening its database. I'm not sure what conditions cause this - I haven't been able to reproduce it myself, I've just had reports on Crashlytics; it looks like it affects only some devices.
Here's my code:
class Database {
static let DB_DIR:URL = {
// Library/LocalDatabase doesn't get backed up to iTunes/iCloud, and it matches our sqlite plugin's default (for Javascript access)
let fileMgr = FileManager.default
let libUrl:URL = try! fileMgr.url(for: .libraryDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
return libUrl.appendingPathComponent("LocalDatabase")
}()
static func getPath(_ dbName:String!) -> String {
return DB_DIR.appendingPathComponent(dbName).path
}
static func createDb(_ dbName:String!) -> FMDatabase {
return FMDatabase(path: getPath(dbName))
}
// only for front- and back-end dbs (TODO - close these when app exits, or open/close for each transaction?)
static func getOpenedDb(_ dbName:String) -> FMDatabase {
let db:FMDatabase = createDb(dbName)
if !db.open() {
fatalError("Unable to open \(dbName)")
}
return db
}
static let BACKEND_DB:FMDatabase = Database.getOpenedDb("mainIosDb")
static let FRONTEND_DB:FMDatabase = Database.getOpenedDb("JsDb")
}
... and here's a crash log:
Crashed: com.rsginc.rmove.TripStorage.singleton
0 libswiftCore.dylib 0x1008c8a18 _TFs16_assertionFailedFTVs12StaticStringSSS_Su5flagsVs6UInt32_Os5Never + 164
1 rMove 0x10022dc88 type metadata accessor for Database (Utilities.swift)
2 rMove 0x10022d320 globalinit_33_2CFFAAA7EF6073F07DB88164E80B793B_func11 (Utilities.swift:177)
3 libdispatch.dylib 0x188c6e1bc _dispatch_client_callout + 16
4 libdispatch.dylib 0x188c6efb0 dispatch_once_f + 56
5 rMove 0x10022d35c Database.BACKEND_DB.unsafeMutableAddressor (Utilities.swift)
6 rMove 0x100213864 TripStorage.init() -> TripStorage (TripStorage.swift:13)
7 rMove 0x100213508 static TripStorage.(getInstance() -> TripStorage).(closure #1) (TripStorage.swift:87)
8 libdispatch.dylib 0x188c6e1bc _dispatch_client_callout + 16
9 libdispatch.dylib 0x188c7b7f0 _dispatch_barrier_sync_f_invoke + 84
10 rMove 0x100213418 static TripStorage.getInstance() -> TripStorage (TripStorage.swift)
11 rMove 0x10020384c specialized CordovaInterface.start(Double, Double, Int, Double, Double, String, Bool, Int, Int, Double, Int, Int, Int, Int) -> () (CordovaInterface.swift)
12 rMove 0x1001fea74 CordovaInterface.configureFromDefaults() -> () (CordovaInterface.swift)
13 rMove 0x1002014fc partial apply (CordovaInterface.swift)
14 rMove 0x10020b1e0 specialized TerminationRecovery.applicationLaunched(notification : NSNotification) -> () (TerminationRecovery.swift)
15 rMove 0x10020a020 #objc TerminationRecovery.applicationLaunched(notification : NSNotification) -> () (TerminationRecovery.swift)
16 CoreFoundation 0x189d7eb10 __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 20
17 CoreFoundation 0x189d7e214 _CFXRegistrationPost + 400
18 CoreFoundation 0x189d7df90 ___CFXNotificationPost_block_invoke + 60
19 CoreFoundation 0x189dedb8c -[_CFXNotificationRegistrar find:object:observer:enumerator:] + 1504
20 CoreFoundation 0x189cbfe64 _CFXNotificationPost + 376
21 Foundation 0x18a7f4e0c -[NSNotificationCenter postNotificationName:object:userInfo:] + 68
22 UIKit 0x18ff1cd38 -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 4196
23 UIKit 0x18ff22808 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1656
24 UIKit 0x18ff37104 __84-[UIApplication _handleApplicationActivationWithScene:transitionContext:completion:]_block_invoke.3139 + 48
25 UIKit 0x18ff1f7ec -[UIApplication workspaceDidEndTransaction:] + 168
26 FrontBoardServices 0x18b9bb92c __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 36
27 FrontBoardServices 0x18b9bb798 -[FBSSerialQueue _performNext] + 176
28 FrontBoardServices 0x18b9bbb40 -[FBSSerialQueue _performNextFromRunLoopSource] + 56
29 CoreFoundation 0x189d92b5c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24
30 CoreFoundation 0x189d924a4 __CFRunLoopDoSources0 + 524
31 CoreFoundation 0x189d900a4 __CFRunLoopRun + 804
32 CoreFoundation 0x189cbe2b8 CFRunLoopRunSpecific + 444
33 UIKit 0x18fd057b0 -[UIApplication _run] + 608
34 UIKit 0x18fd00534 UIApplicationMain + 208
35 rMove 0x100103b00 main (main.m:32)
36 libdispatch.dylib 0x188ca15b8 (Missing)
This line in the stack trace:
2 rMove 0x10022d320 globalinit_33_2CFFAAA7EF6073F07DB88164E80B793B_func11 (Utilities.swift:177)
Corresponds with this line in the code:
static let BACKEND_DB:FMDatabase = Database.getOpenedDb("mainIosDb")
My guess and hope is that there's some great information in that stack trace which points directly at the cause of this issue and I just don't know how to interpret it.

You have to open database with flags,
try belloe code it works for me
[self.database openWithFlags:SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_FILEPROTECTION_NONE];

Swift crash reports don't make sense to me

This is the crash log I got from Crashlytics:
Thread : Crashed: com.apple.main-thread
0 Trenìt! 0x1000b93e4 SearchHistoryProvider.getMostRecentStations(Int) -> [String] (SearchHistoryProvider.swift)
1 Trenìt! 0x10007985c specialized MasterViewController.onTouchedTextField(UITextField) -> () (MasterViewController.swift:265)
2 Trenìt! 0x100075414 #objc MasterViewController.onTouchedTextField(UITextField) -> () (MasterViewController.swift)
3 UIKit 0x186fa0ad0 -[UIApplication sendAction:to:from:forEvent:] + 100
4 UIKit 0x186fa0a4c -[UIControl sendAction:to:forEvent:] + 80
5 UIKit 0x186f88740 -[UIControl _sendActionsForEvents:withEvent:] + 436
6 UIKit 0x186fa9248 -[UIControl touchesBegan:withEvent:] + 400
7 UIKit 0x186f9fdc0 -[UIWindow _sendTouchesForEvent:] + 376
8 UIKit 0x186f98b08 -[UIWindow sendEvent:] + 784
9 UIKit 0x186f68f4c -[UIApplication sendEvent:] + 248
10 UIKit 0x186f67528 _UIApplicationHandleEventQueue + 6568
11 CoreFoundation 0x181dd5124 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24
12 CoreFoundation 0x181dd4bb8 __CFRunLoopDoSources0 + 540
13 CoreFoundation 0x181dd28b8 __CFRunLoopRun + 724
14 CoreFoundation 0x181cfcd10 CFRunLoopRunSpecific + 384
15 GraphicsServices 0x1835e4088 GSEventRunModal + 180
16 UIKit 0x186fd1f70 UIApplicationMain + 204
17 Trenìt! 0x10009b2fc main (AppDelegate.swift:14)```
(edited)
and this is my code:
MasterViewController.swift:
263 func showRecentStations(textField: UITextField) {
264 textField.text = ""
265 suggestionStations = masterContainerManager!.homeController?.searchHistoryProvider?.getMostRecentStations(10)
266 updateStationsTable(textField)
267 }
SearchHistoryProvider.swift
func getMostRecentStations (maxSize : Int) -> [String] {
let stationsByOldestArray = getRecentStationsByOldest()
let stations = NSMutableOrderedSet()
for i in (0...(stationsByOldestArray.count-1)).reverse() {
stations.addObject(stationsByOldestArray[i].depStation)
if stations.count==maxSize {
return stations.array as! [String]
}
stations.addObject(stationsByOldestArray[i].arrStation)
if stations.count==maxSize {
return stations.array as! [String]
}
}
return stations.array as! [String]
}
Can anyone understand what's the crash about?

I found the bug:
in case stationsByOldestArray.count was 0
the for loop would have been
for i in (0...-1).reverse()
I fixed it by rewriting the loop as
for i in (0..<stationsByOldestArray.count).reverse()
However I think the Swift crash reports are often hopelessly unhelpful!