Initializing realm globally causing a crash - ios

Question

I have a swift app with realm integrated to it. I am declaring the realm globally in the AppDelegate.swift as shown below in the code. When I execute this application, My app runs fine on the devices and even in the test mode.
Issue:
After my app submission, the Apple review board rejected app and the symbolicated crash logs pointed the initialisation of the realm.
Below is the code, what am I possibly doing wrong?
import UIKit
import CoreData
import Firebase
import UserNotifications
import Fabric
import RealmSwift
var uiRealm = try! Realm()
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, MessagingDelegate {
var window: UIWindow?
let gcmMessageIDKey = "gcm.message_id"
var tokenExists = false
let imageDb = DigitalFingerprint()
var uid: String!
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
#if DEVELOPMENT
print("Development Mode Started")
let filePath = Bundle.main.path(forResource: "GoogleService-Info", ofType: "plist")
guard let fileopts = FirebaseOptions.init(contentsOfFile: filePath!)
else {
fatalError("Couldn't load config file")
}
FirebaseApp.configure(options: fileopts)
#else
print("Production Mode Started")
FirebaseApp.configure()
#endif
Auth.auth().addStateDidChangeListener { (auth, user) in
if (user != nil) {
print("User is there")
self.uid = KeychainWrapper.standard.string(forKey: KEY_UID)
} else {
print("user signed out")
DB_URL.removeAllObservers()
DispatchQueue.main.async {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "starts") as? BootVC
var topRootViewController: UIViewController = (UIApplication.shared.keyWindow?.rootViewController)!
while((topRootViewController.presentedViewController) != nil){
topRootViewController = topRootViewController.presentedViewController!
}
topRootViewController.present(vc!, animated: true, completion: nil)
}
}
}
if uid != nil {
checkforAccess()
}
return true
}
Following is the Real object, DigitalFingerprint.swift
import Foundation
import RealmSwift
import UIKit
class DigitalFingerprint: Object {
#objc dynamic var imageData: Data? = nil
#objc dynamic var fid : String? = nil
#objc dynamic var uid : String? = nil
override static func primaryKey() -> String {
return "uid"
}
}
extension DigitalFingerprint {
func writeToRealm(){
try! uiRealm.write {
uiRealm.add(self, update: true)
}
}
func DeleteFromRealm(object: Results<DigitalFingerprint>){
try! uiRealm.write {
uiRealm.delete(object)
}
}
}
crash Logs received by apple review board. :
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
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0 libsystem_kernel.dylib 0x00000001830142e8 __pthread_kill + 8
1 libsystem_pthread.dylib 0x00000001831292f8 pthread_kill$VARIANT$mp + 396
2 libsystem_c.dylib 0x0000000182f83060 __abort + 152
3 libsystem_c.dylib 0x0000000182f82fc8 __abort + 0
4 libc++abi.dylib 0x000000018271f068 __cxa_bad_cast + 0
5 libc++abi.dylib 0x000000018271f1f8 default_terminate_handler+ 8696 () + 280
6 libobjc.A.dylib 0x0000000182748820 _objc_terminate+ 34848 () + 140
7 SpotMi 0x0000000100dc7d78 CLSTerminateHandler() + 1260920 (CLSException.mm:314)
8 libc++abi.dylib 0x000000018273754c std::__terminate(void (*)+ 107852 ()) + 16
9 libc++abi.dylib 0x00000001827375b8 std::terminate+ 107960 () + 60
10 Realm 0x0000000101f94a00 realm::Realm::open_with_config(realm::Realm::Config const&, std::__1::unique_ptr<realm::Replication, std::__1::default_delete<realm::Replication> >&, std::__1::unique_ptr<realm::SharedGroup, std::__1::default_delete<realm::SharedGroup> >&, std::__1::unique_ptr<realm::Group, std::__1::default_delete<realm::Group> >&, realm::Realm*) + 985600 (memory:3006)
11 Realm 0x0000000101f944e0 realm::Realm::Realm(realm::Realm::Config, std::__1::shared_ptr<realm::_impl::RealmCoordinator>) + 984288 (shared_realm.cpp:55)
12 Realm 0x0000000101ed9658 realm::Realm::make_shared_realm(realm::Realm::Config, std::__1::shared_ptr<realm::_impl::RealmCoordinator>)::make_shared_enabler::make_shared_enabler(realm::Realm::Config, std::__1::shared_ptr<realm::_impl::RealmCoordinator>) + 218712 (shared_realm.hpp:304)
13 Realm 0x0000000101ed94cc std::__1::shared_ptr<realm::Realm::make_shared_realm(realm::Realm::Config, std::__1::shared_ptr<realm::_impl::RealmCoordinator>)::make_shared_enabler> std::__1::shared_ptr<realm::Realm::make_shared_realm(realm::Realm::Config, std::__1::shared_ptr<realm::_impl::RealmCoordinator>)::make_shared_enabler>::make_shared<realm::Realm::Config, std::__1::shared_ptr<realm::_impl::RealmCoordinator> >(realm::Realm::Config&&, std::__1::shared_ptr<realm::_impl::RealmCoordinator>&&) + 218316 (memory:2172)
14 Realm 0x0000000101ed56a4 realm::_impl::RealmCoordinator::get_realm(realm::Realm::Config) + 202404 (realm_coordinator.cpp:229)
15 Realm 0x0000000101f965f0 realm::Realm::get_shared_realm(realm::Realm::Config) + 992752 (shared_realm.cpp:250)
16 Realm 0x0000000101f7016c +[RLMRealm realmWithConfiguration:error:] + 835948 (RLMRealm.mm:400)
17 RealmSwift 0x00000001023911e4 Realm.init() + 152036 (Realm.swift:0)
18 RealmSwift 0x0000000102391178 Realm.__allocating_init() + 151928 (Realm.swift:0)
19 SpotMi 0x0000000100c9be14 globalinit_33_E3853139275E4567E078AE3BFE0165A3_func0 + 32276 (AppDelegate.swift:23)
20 libdispatch.dylib 0x0000000182e7ea14 _dispatch_client_callout + 16
21 libdispatch.dylib 0x0000000182e82240 dispatch_once_f$VARIANT$mp + 60
22 SpotMi 0x0000000100cc2254 FeedVC.viewDidLoad() + 189012 (FeedVC.swift:84)
23 SpotMi 0x0000000100cc2650 #objc FeedVC.viewDidLoad() + 190032 (FeedVC.swift:0)
24 UIKit 0x000000018c9e3ae8 -[UIViewController loadViewIfRequired] + 1040
25 UIKit 0x000000018c9e36c0 -[UIViewController view] + 28
26 UIKit 0x000000018c9ea28c -[UIWindow addRootViewControllerViewIfPossible] + 136
27 UIKit 0x000000018c9e74ec -[UIWindow _setHidden:forced:] + 272
28 UIKit 0x000000018ca563a0 -[UIWindow makeKeyAndVisible] + 48
29 UIKit 0x000000018cc43d10 -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 3620
30 UIKit 0x000000018cc48aa8 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1712
31 UIKit 0x000000018cee42d4 __111-[__UICanvasLifecycleMonitor_Compatability _scheduleFirstCommitForScene:transition:firstActivation:completion:]_block_invoke + 800
32 UIKit 0x000000018d1bc12c +[_UICanvas _enqueuePostSettingUpdateTransactionBlock:] + 160
33 UIKit 0x000000018cee3f38 -[__UICanvasLifecycleMonitor_Compatability _scheduleFirstCommitForScene:transition:firstActivation:completion:] + 252
34 UIKit 0x000000018cee4798 -[__UICanvasLifecycleMonitor_Compatability activateEventsOnly:withContext:completion:] + 732
35 UIKit 0x000000018d6697d0 __82-[_UIApplicationCanvas _transitionLifecycleStateWithTransitionContext:completion:]_block_invoke + 260
36 UIKit 0x000000018d669674 -[_UIApplicationCanvas _transitionLifecycleStateWithTransitionContext:completion:] + 448
37 UIKit 0x000000018d3d72dc __125-[_UICanvasLifecycleSettingsDiffAction performActionsForCanvas:withUpdatedScene:settingsDiff:fromSettings:transitionContext:]_block_invoke + 220
38 UIKit 0x000000018d5703dc _performActionsWithDelayForTransitionContext + 112
39 UIKit 0x000000018d3d718c -[_UICanvasLifecycleSettingsDiffAction performActionsForCanvas:withUpdatedScene:settingsDiff:fromSettings:transitionContext:] + 252
40 UIKit 0x000000018d1bb78c -[_UICanvas scene:didUpdateWithDiff:transitionContext:completion:] + 364
41 UIKit 0x000000018cc471ec -[UIApplication workspace:didCreateScene:withTransitionContext:completion:] + 540
42 UIKit 0x000000018d05cde8 -[UIApplicationSceneClientAgent scene:didInitializeWithEvent:completion:] + 364
43 FrontBoardServices 0x0000000185bc61f0 -[FBSSceneImpl _didCreateWithTransitionContext:completion:] + 364
44 FrontBoardServices 0x0000000185bceaf8 __56-[FBSWorkspace client:handleCreateScene:withCompletion:]_block_invoke_2 + 224
45 libdispatch.dylib 0x0000000182e7ea14 _dispatch_client_callout + 16
46 libdispatch.dylib 0x0000000182e86200 _dispatch_block_invoke_direct$VARIANT$mp + 288
47 FrontBoardServices 0x0000000185bfa7f8 __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 36
48 FrontBoardServices 0x0000000185bfa49c -[FBSSerialQueue _performNext] + 404
49 FrontBoardServices 0x0000000185bfaa38 -[FBSSerialQueue _performNextFromRunLoopSource] + 56
50 CoreFoundation 0x00000001834aa97c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24
51 CoreFoundation 0x00000001834aa8fc __CFRunLoopDoSource0 + 88
52 CoreFoundation 0x00000001834aa184 __CFRunLoopDoSources0 + 204
53 CoreFoundation 0x00000001834a7d5c __CFRunLoopRun + 1048
54 CoreFoundation 0x00000001833c7e58 CFRunLoopRunSpecific + 436
55 GraphicsServices 0x0000000185274f84 GSEventRunModal + 100
56 UIKit 0x000000018ca4767c UIApplicationMain + 236
57 SpotMi 0x0000000100c99b4c main + 23372 (SurpriseCell.swift:26)
58 libdyld.dylib 0x0000000182ee456c start + 4
And I am calling this function also in my initialviewcontroller(Feedvc), in the viewDidAppear()
The flow of my program is
1.load feedvc
if the user is nil
Go to the bootVc(thats called from app delegate)
Again what exactly am i doing wrong?
Also, will just declaring a variable of type realm globally and then initialzing the variable in didFinishLaunching() be a better option?
Thanks!

Answer 1

Well, it is not a good idea to create variables outside the class. Try to create
var uiRealm = try! Realm()
inside the AppDelegate class. And use (UIApplication.shared.delegate as! AppDelegate).uiRealm in other classes.