Add guaranteed non-nil name for itemstack

storage/itemstack.lua

@@ -112,6 +112,30 @@ function ItemStack:getDisplayName()
   return self.displayName
 end
 
+function ItemStack:getSimpleName()
+  local displayName = self:getDisplayName()
+  if displayName ~= nil then
+    return displayName
+  end
+
+  local name = self:getName()
+  if name ~= nil then
+    local _, e = name:find(":")
+    if e == nil then
+      return name
+    end
+
+    local simpleName = name:sub(e + 1)
+    if #simpleName == 0 then
+      return name
+    end
+
+    return simpleName
+  end
+
+  return self:getInventory():getName().."["..self:getSlot().."]"
+end
+
 function ItemStack:hasChanged(listObj, thorough)
   local listItem = listObj[self.slot]
   if listItem == nil or listItem.name ~= self.name or listItem.count ~= self.count then