Fix potential crash due to race condition in timeline gap filling

ScaledMetric.wrappedValue calls into Font.scaleFactor(textStyle:in:)
which uses a dictionary setter

Tusker/Screens/Large Image/Transitions/LargeImageInteractionController.swift

@@ -25,7 +25,14 @@ class LargeImageInteractionController: UIPercentDrivenInteractiveTransition {
     }
     
     @objc func handleGesture(_ recognizer: UIPanGestureRecognizer) {
-        let translation = recognizer.translation(in: recognizer.view!.superview!)
+        guard let recognizerSuperview = recognizer.view?.superview else {
+            // Assume the gesture has ended b/c we don't have a view/superview anymore.
+            inProgress = false
+            direction = nil
+            cancel()
+            return
+        }
+        let translation = recognizer.translation(in: recognizerSuperview)
         var progress = translation.y / 200
         if let direction = direction {
             progress *= direction
@@ -63,7 +70,7 @@ class LargeImageInteractionController: UIPercentDrivenInteractiveTransition {
     
     override func cancel() {
         super.cancel()
-        viewController.isInteractivelyAnimatingDismissal = false
+        viewController?.isInteractivelyAnimatingDismissal = false
     }
     
 }

Tusker/Screens/Main/MainSplitViewController.swift

@@ -214,6 +214,10 @@ extension MainSplitViewController: UISplitViewControllerDelegate {
         if item == sidebar.selectedItem {
             itemNavStack = secondaryNavController.viewControllers
             secondaryNavController.viewControllers = []
+            // Sometimes removing a VC from the viewControllers array doesn't immediately remove it's view from the hierarchy
+            for vc in itemNavStack {
+                vc.viewIfLoaded?.removeFromSuperview()
+            }
         } else {
             itemNavStack = navigationStacks[item] ?? []
             navigationStacks.removeValue(forKey: item)
@@ -339,6 +343,11 @@ extension MainSplitViewController: UISplitViewControllerDelegate {
         let viewControllersToMove = navController.viewControllers.dropFirst(skipFirst)
         navController.viewControllers.removeLast(navController.viewControllers.count - skipFirst)
         
+        // Sometimes removing a VC from the viewControllers array doesn't immediately remove it's view from the hierarchy
+        for vc in viewControllersToMove {
+            vc.viewIfLoaded?.removeFromSuperview()
+        }
+        
         if let prepend = prepend {
             navigationStacks[item] = [prepend] + viewControllersToMove
         } else {

Tusker/Screens/Onboarding/InstanceSelectorTableViewController.swift

@@ -150,7 +150,8 @@ class InstanceSelectorTableViewController: UITableViewController {
     private func updateSpecificInstance(domain: String) {
         activityIndicator.startAnimating()
         
-        guard let components = parseURLComponents(input: domain) else {
+        guard let components = parseURLComponents(input: domain),
+              let url = components.url else {
             var snapshot = dataSource.snapshot()
             if snapshot.indexOfSection(.selected) != nil {
                 snapshot.deleteSections([.selected])
@@ -159,7 +160,6 @@ class InstanceSelectorTableViewController: UITableViewController {
             activityIndicator.stopAnimating()
             return
         }
-        let url = components.url!
 
         let client = Client(baseURL: url, session: .appDefault)
         let request = Client.getInstance()

Tusker/Screens/Timeline/TimelineViewController.swift

@@ -1166,7 +1166,10 @@ extension TimelineViewController {
         let addedItems: Bool
         
         let statusItems = snapshot.itemIdentifiers(inSection: .statuses)
-        let gapIndex = statusItems.firstIndex(of: .gap)!
+        guard let gapIndex = statusItems.firstIndex(of: .gap) else {
+            // Not sure how this is reachable (maybe the gap cell was tapped twice and the requests raced?) but w/e
+            return
+        }
         
         switch direction {
         case .above:
@@ -1293,6 +1296,9 @@ extension TimelineViewController: UICollectionViewDelegate {
                 selected(status: status.reblog?.id ?? id, state: collapseState.copy())
             }
         case .gap:
+            guard controller.state == .idle else {
+                return
+            }
             let cell = collectionView.cellForItem(at: indexPath) as! TimelineGapCollectionViewCell
             cell.showsIndicator = true
             Task {

Tusker/Views/AccountDisplayNameView.swift

@@ -38,6 +38,7 @@ struct AccountDisplayNameView: View {
         let matches = emojiRegex.matches(in: account.displayName, options: [], range: fullRange)
         guard !matches.isEmpty else { return }
         
+        let emojiSize = self.emojiSize
         let emojiImages = MultiThreadDictionary<String, Image>()
         
         let group = DispatchGroup()