[BUG] Dragging and dropping an item from the Equipped collection onto itself in the Main collection causes an exception

trueh · Mar 25, 2023

Hello:

If I have an item equipped and I drag it back onto itself in the main collection, an exception is produced and the item gets deleted. I am using tthe latest version of Ultimate Inventory System on Unity 2021.3.18f1 (LTS) with the built-in rendering pipeline.

The steps to reproduce can be seen in this video: https://streamable.com/dd4x28

The exception produced is the following:


[Exception] NullReferenceException: Object reference not set to an instance of an object
ItemSlotCollection.GetItemSlotIndex() at /Opsive/UltimateInventorySystem/Scripts/Core/InventoryCollections/ItemSlotCollection.cs:496
494:   if (m_ItemsBySlot[i].Item == item) { return i; }
-->496:   if (m_ItemsBySlot[i].Item.StackableEquivalentTo(item)) {
497:       stackableEquivalentItemIndex = i;
498:   }

ItemSlotCollection.RemoveItem() at /Opsive/UltimateInventorySystem/Scripts/Core/InventoryCollections/ItemSlotCollection.cs:432
430:   public override ItemInfo RemoveItem(ItemInfo itemInfo)
431:   {
-->432:       var itemSlot = GetItemSlotIndex(itemInfo.Item);
433:       if (itemSlot == -1) {
434:           return (0, itemInfo.Item, this);

Inventory.RemoveItem() at /Opsive/UltimateInventorySystem/Scripts/Core/InventoryCollections/Inventory.cs:517
515:   public virtual ItemInfo RemoveItem(ItemInfo itemInfo)
516:   {
-->517:       if (ReferenceEquals(itemInfo.Inventory, this)) { return itemInfo.ItemCollection.RemoveItem(itemInfo); }
519:       return MainItemCollection.RemoveItem(itemInfo);

InventoryGrid.RemoveItem() at /Opsive/UltimateInventorySystem/Scripts/UI/Item/InventoryGrid.cs:149
147:   public override ItemInfo RemoveItem(ItemInfo itemInfo, int index)
148:   {
-->149:       return Inventory.RemoveItem(itemInfo);
150:   }

ItemViewDropContainerSmartExchangeAction.Drop() at /Opsive/UltimateInventorySystem/Scripts/UI/Item/DragAndDrop/DropActions/ItemViewDropContainerSmartExchangeAction.cs:154
153:   if (destinationGiveSourceReceive) {
-->154:       itemViewDropHandler.StreamData.DestinationItemInfo = itemViewDropHandler.DestinationContainer.RemoveItem(itemViewDropHandler.StreamData.DestinationItemInfo, itemViewDropHandler.DestinationIndex);
155:   }

ItemViewDropActionsWithConditions.Drop() at /Opsive/UltimateInventorySystem/Scripts/UI/Item/DragAndDrop/ItemViewSlotDropActionSet.cs:235
233:       public void Drop(ItemViewDropHandler itemViewDropHandler)
234:       {
-->235:           for (int i = 0; i < m_Actions.Length; i++) { m_Actions[i].Drop(itemViewDropHandler); }
236:       }
237:   }

ItemViewSlotDropActionSet.HandleItemViewSlotDrop() at /Opsive/UltimateInventorySystem/Scripts/UI/Item/DragAndDrop/ItemViewSlotDropActionSet.cs:116
114:       if (index == -1) { return; }
-->116:       m_ActionsWithConditions[index].Drop(itemViewDropHandler);
117:   }

ItemViewDropHandler.HandleItemViewSlotDropInternal() at /Opsive/UltimateInventorySystem/Scripts/UI/Item/DragAndDrop/ItemViewDropHandler.cs:259
257:   {
258:       if (m_ItemViewSlotDropActionSet == null) { return; }
-->259:       m_ItemViewSlotDropActionSet.HandleItemViewSlotDrop(this);
261:       if (SourceContainer != null) {

ItemViewDropHandler.HandleItemViewSlotDrop() at /Opsive/UltimateInventorySystem/Scripts/UI/Item/DragAndDrop/ItemViewDropHandler.cs:249
248:       m_ItemViewSlotCursorManager.BeforeDrop();
-->249:       HandleItemViewSlotDropInternal();
250:       m_ItemViewSlotCursorManager.RemoveItemView();
251:   }

ItemViewSlotsContainerBase+<>c__DisplayClass78_0.<Initialize>b__7() at /Opsive/UltimateInventorySystem/Scripts/UI/Item/ItemViewSlotsContainerBase.cs:275
273:           m_ItemViewSlotDropEventData.SetValues(this, localIndex);
274:           m_ItemViewSlotDropEventData.PointerEventData = pointerEventData;
-->275:           OnItemViewSlotDropE?.Invoke(m_ItemViewSlotDropEventData);
276:       };
277:   }

ActionButton.OnDrop() at /Opsive/UltimateInventorySystem/Scripts/UI/CompoundElements/ActionButton.cs:264
262:   public virtual void OnDrop(PointerEventData eventData)
263:   {
-->264:       OnDropE?.Invoke(eventData);
265:   }

ExecuteEvents.Execute() at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/ExecuteEvents.cs:92
90:   private static void Execute(IDropHandler handler, BaseEventData eventData)
91:   {
-->92:       handler.OnDrop(ValidateEventData<PointerEventData>(eventData));
93:   }

ExecuteEvents.Execute[T]() at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/ExecuteEvents.cs:272
270:   try
271:   {
-->272:       functor(arg, eventData);
273:   }
274:   catch (Exception e)

ExecuteEvents.ExecuteHierarchy()

RewiredStandaloneInputModule.ProcessMousePress() at /Rewired/Integration/UnityUI/RewiredStandaloneInputModule.cs:1093
1091:       ExecuteEvents.Execute(pointerEvent.pointerPress, pointerEvent, ExecuteEvents.pointerClickHandler);
1092:   } else if (pointerEvent.pointerDrag != null && pointerEvent.dragging) {
-->1093:       ExecuteEvents.ExecuteHierarchy(currentOverGo, pointerEvent, ExecuteEvents.dropHandler);
1094:   }

RewiredStandaloneInputModule.ProcessMouseEvent() at /Rewired/Integration/UnityUI/RewiredStandaloneInputModule.cs:992
991:   // Process the first mouse button fully
-->992:   ProcessMousePress(leftButtonData);
993:   ProcessMove(leftButtonData.buttonData);
994:   ProcessDrag(leftButtonData.buttonData);

RewiredStandaloneInputModule.ProcessMouseEvents() at /Rewired/Integration/UnityUI/RewiredStandaloneInputModule.cs:976
974:       int pointerCount = GetMouseInputSourceCount(playerIds[i]);
975:       for(int j = 0; j < pointerCount; j++) {
-->976:           ProcessMouseEvent(playerIds[i], j);
977:       }
978:   }

RewiredStandaloneInputModule.Process() at /Rewired/Integration/UnityUI/RewiredStandaloneInputModule.cs:690
688:       // touch needs to take precedence because of the mouse emulation layer
689:       if (!ProcessTouchEvents()) {
-->690:           if (isMouseSupported) ProcessMouseEvents();
691:       }
692:   }

EventSystem.Update() at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/EventSystem.cs:501
500:               if (!changedModule && m_CurrentInputModule != null)
-->501:                   m_CurrentInputModule.Process();
503:   #if UNITY_EDITOR

Regards.

trueh · Mar 25, 2023

This one can be solved in ItemSlotCollection.cs changing from:

Code:

public int GetItemSlotIndex(Item item){

var stackableEquivalentItemIndex = -1;
for (int i = 0; i < m_ItemSlotSet.ItemSlots.Count; i++) {
var itemSlot = m_ItemSlotSet.ItemSlots[i];
if (itemSlot.Category != null && !itemSlot.Category.InherentlyContains(item)) {
continue;
}

if (m_ItemsBySlot[i] == null) { continue; }

if (m_ItemsBySlot[i].Item == item) { return i; }

if (m_ItemsBySlot[i].Item.StackableEquivalentTo(item)) {
stackableEquivalentItemIndex = i;
}
}

return stackableEquivalentItemIndex;
}

to:

Code:

public int GetItemSlotIndex(Item item){

var stackableEquivalentItemIndex = -1;
for (int i = 0; i < m_ItemSlotSet.ItemSlots.Count; i++) {
var itemSlot = m_ItemSlotSet.ItemSlots[i];
if (itemSlot.Category != null && !itemSlot.Category.InherentlyContains(item)) {
continue;
}

if (m_ItemsBySlot[i] == null) { continue; }

if (m_ItemsBySlot[i].Item == null) { continue; }

if (m_ItemsBySlot[i].Item == item) { return i; }

if (m_ItemsBySlot[i].Item.StackableEquivalentTo(item)) {
stackableEquivalentItemIndex = i;
}
}

return stackableEquivalentItemIndex;
}

I have just added

Code:

if (m_ItemsBySlot[i].Item == null) { continue; }

Regards.

Sangemdoko · Mar 27, 2023

Thank you for letting us know. There was a change that now allows null items in the ItemSlotCollection in the last update. I must have missed this exception.
I've added your change in the source code

[BUG] Dragging and dropping an item from the Equipped collection onto itself in the Main collection causes an exception

trueh

New member

trueh

New member

Sangemdoko

Moderator