Fixed Tomato farming (again)

scripts/CSharp/Common/Inventory/InventoryInstance.cs

@@ -17,6 +17,9 @@ public partial class InventoryInstance : Node
     [Signal]
     public delegate void InventoryContentsChangedEventHandler();
 
+    /// <summary>
+    /// The total amount of Inventoryslots in the inventory (empty and occupied).
+    /// </summary>
     [Export]
     public int SlotAmount
     {
@@ -49,7 +52,7 @@ public partial class InventoryInstance : Node
     private InventoryActionResult AddItemAndStackRecursive(ItemInstance newItem, int slotSearch)
     {
         if (newItem.blueprint == null || newItem.amount == 0)
-            return InventoryActionResult.SourceDoesNotExists;
+            return InventoryActionResult.SourceDoesNotExist;
 
         var slotIndex = -1;
         // find stackable slot
@@ -97,7 +100,7 @@ public partial class InventoryInstance : Node
         if (inventorySlot < 0 || inventorySlot >= _slots.Count)
         {
             itemInstance = null;
-            return InventoryActionResult.SourceDoesNotExists;
+            return InventoryActionResult.SourceDoesNotExist;
         }
 
         if (_slots[inventorySlot].IsEmpty())
@@ -107,6 +110,10 @@ public partial class InventoryInstance : Node
         }
 
         itemInstance = _slots[inventorySlot].itemInstance;
+        if (itemInstance == null)
+            return InventoryActionResult.SourceDoesNotExist;
+        
+        itemInstance.amount -= 1;
         _slots[inventorySlot].itemInstance = null;
         EmitSignal(SignalName.InventoryContentsChanged);
         return InventoryActionResult.Success;
@@ -120,7 +127,7 @@ public partial class InventoryInstance : Node
     public InventoryActionResult AddItemToSlot(ItemInstance itemInstance, int destinationSlot)
     {
         if (destinationSlot < 0 || destinationSlot >= _slots.Count)
-            return InventoryActionResult.DestinationDoesNotExists;
+            return InventoryActionResult.DestinationDoesNotExist;
 
         if (!_slots[destinationSlot].IsEmpty())
             return InventoryActionResult.DestinationFull;