From fc8fcb76fd72313ad2413a4d7219622eaa4d47fe Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Mon, 5 Dec 2022 17:17:34 -0500
Subject: [PATCH] Fix crash when TimelineViewController tries to apply snapshot
 while not visible

---
 Tusker/Screens/Timeline/TimelineViewController.swift | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/Tusker/Screens/Timeline/TimelineViewController.swift b/Tusker/Screens/Timeline/TimelineViewController.swift
index e7ff454f..cb833424 100644
--- a/Tusker/Screens/Timeline/TimelineViewController.swift
+++ b/Tusker/Screens/Timeline/TimelineViewController.swift
@@ -522,10 +522,12 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
     
     private func applySnapshot(_ snapshot: NSDiffableDataSourceSnapshot<Section, Item>, maintainingScreenPosition offsetFromTop: CGFloat, ofItem itemToMaintain: Item) {
         // use a snapshot of the collection view to hide the flicker as the content offset changes and then changes back
-        let snapshotView = collectionView.snapshotView(afterScreenUpdates: false)!
-        snapshotView.layer.zPosition = 1000
-        snapshotView.frame = view.bounds
-        view.addSubview(snapshotView)
+        let snapshotView = collectionView.snapshotView(afterScreenUpdates: false)
+        if let snapshotView {
+            snapshotView.layer.zPosition = 1000
+            snapshotView.frame = view.bounds
+            view.addSubview(snapshotView)
+        }
         
         dataSource.apply(snapshot, animatingDifferences: false) {
             if let indexPathOfItemToMaintain = self.dataSource.indexPath(for: itemToMaintain) {
@@ -558,7 +560,7 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
                 self.collectionView.contentOffset.y -= offsetFromTop
             }
             
-            snapshotView.removeFromSuperview()
+            snapshotView?.removeFromSuperview()
         }
     }