Made upmost and root viewcontrollers optional

Author: Thomas Roovers

.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
 
   s.name         = "Einsteinium"
-  s.version      = "1.2.4"
+  s.version      = "1.3.0"
   s.author       = { "Bas van Kuijck" => "[email protected]" }
   s.license      = { :type => "MIT", :file => "LICENSE" }
   s.homepage     = "http://www.e-sites.nl"
@@ -10,4 +10,5 @@ Pod::Spec.new do |s|
   s.source_files = "Sources/**/*.{h,swift}"
   s.platform     = :ios, '9.0'
   s.requires_arc = true
+  s.dependency 'Logging'
 end

Einsteinium.podspec

@@ -10,11 +10,14 @@ let package = Package(
         .library(name: "Einsteinium", targets: ["Einsteinium"])
     ],
     dependencies: [
+        .package(url: "https://github.com/apple/swift-log.git", from: "1.0.0"),
     ],
     targets: [
         .target(
             name: "Einsteinium",
-            dependencies: [ ],
+            dependencies: [
+                "Logging"
+            ],
             path: "Sources"
         )
     ]

Package.resolved

@@ -0,0 +1,8 @@
+//
+//  Logging.swift
+//  Created by Thomas Roovers on 16/12/2021.
+//
+
+import Logging
+
+let logger = Logger(label: "einsteinium")

Package.swift

@@ -8,13 +8,14 @@
 
 import Foundation
 import UIKit
+import Logging
 
 extension UIViewController {
-    public class var upmost: UIViewController {
+    public class var upmost: UIViewController? {
         var viewController = root
         while true {
-            if let pres = viewController.presentedViewController, pres.isBeingDismissed == false {
-                viewController = pres
+            if let presentedViewController = viewController?.presentedViewController, presentedViewController.isBeingDismissed == false {
+                viewController = presentedViewController
             } else {
                 break
             }
@@ -23,14 +24,17 @@ extension UIViewController {
         return viewController
     }
 
-    public class var root: UIViewController {
+    public class var root: UIViewController? {
         guard let window = UIApplication.shared.keyWindow else {
-            preconditionFailure("No keyWindow")
+            logger.error("No keyWindow")
+            return nil
         }
 
         guard let viewController = window.rootViewController else {
-            preconditionFailure("No rootViewController")
+            logger.error("No rootViewController")
+            return nil
         }
+        
         return viewController
     }
 }