fix crash due nil itemstack (#13)

* fix crashes due nil itemstacks

home_vending_machines/api.lua

@@ -28,6 +28,7 @@ local function reg_simple(name, def)
             end
         end,
         on_rightclick = function(pos, node, clicker, itemstack, pointed_thing)
+            if not itemstack then return end
             local pname = clicker:get_player_name()
             local iname = itemstack:get_name()
             local dpos = vector.add((vector.multiply(minetest.facedir_to_dir(node.param2), -1)), pos)

home_workshop_misc/init.lua

@@ -44,6 +44,7 @@ minetest.register_node("home_workshop_misc:beer_tap", {
 	},
 	on_rightclick = function(pos, node, clicker, itemstack, pointed_thing)
 		local inv = clicker:get_inventory()
+		if not itemstack then return end
 
 		local wieldname = itemstack:get_name()
 		if wieldname == "vessels:drinking_glass" then