Fix client freeze when replacing a daily quest with a daily from the same trader

project/SPT.SinglePlayer/Patches/MainMenu/QuestAddedAutoSelectPatch.cs

@@ -0,0 +1,46 @@
+using EFT.UI;
+using SPT.Reflection.Patching;
+using System.Reflection;
+using HarmonyLib;
+
+namespace SPT.SinglePlayer.Patches.MainMenu
+{
+    /// <summary>
+    /// BSG added a new handler that's called when a new quest is added to the quest list, this handler results in the first quest in
+    /// a trader's task list being selected whenever a new quest is added. This has the negative effect of breaking replacing dailies
+    /// for a trader with a daily from that same trader, due to the selection happening _before_ the daily is removed. Essentially 
+    /// resulting in a race condition where the code to remove the old daily tries to remove the trader's first quest instead.
+    /// 
+    /// We can work around it by conditioning the call to `AutoSelectQuest` in QuestAddedHandler. This does cause a change in behaviour
+    /// from live, but fixes the client freezing when getting a new daily from the trader you're replacing the daily on.
+    /// 
+    /// Note: While this fixes a BSG bug, we can't avoid fixing it, because it causes the UI to freeze when replacing daily quests
+    ///       We can retire this patch once BSG fixes the underlying bug.
+    ///       
+    /// Testing: You can test if this issue still occurs by disabling this patch, creating a Bear SPT Dev profile, and accepting then
+    ///          replacing a daily task on Fence. If the UI doesn't freeze up, BSG has fixed the bug
+    /// </summary>
+    internal class QuestAddedAutoSelectPatch : ModulePatch
+    {
+        protected override MethodBase GetTargetMethod()
+        {
+            return AccessTools.Method(typeof(QuestsListView), nameof(QuestsListView.QuestAddedHandler));
+        }
+
+        [PatchPrefix]
+        public static bool PatchPrefix(QuestsListView __instance, QuestListItem ____questListItemSelected, QuestListItem view)
+        {
+            // The content of this patch should match QuestsListView::QuestAddedHandler, with the call to `AutoSelectQuest` wrapped in a null check
+            __instance.UpdateSingleQuestVisibility(view);
+
+            // The only reason I can think to call AutoSelectQuest would be if the current selected quest is null, to select the first quest
+            // added to the list, if you somehow get a quest while on the trader task list
+            if (____questListItemSelected == null)
+            {
+                __instance.AutoSelectQuest();
+            }
+
+            return false;
+        }
+    }
+}

project/SPT.SinglePlayer/SPTSingleplayerPlugin.cs

@@ -46,6 +46,7 @@ namespace SPT.SinglePlayer
                 new ScavSellAllPriceStorePatch().Enable();
                 new ScavSellAllRequestPatch().Enable();
                 new ScavRepAdjustmentPatch().Enable();
+                new QuestAddedAutoSelectPatch().Enable();
 
                 // 3.10.0
                 new DisableWelcomeToPVEModeMessagePatch().Enable();