Buying an item with a full backpack consumes resources, but does not give the item

If I buy a product (Shop) when my backpack is full, I will spend resources, but the item will not be given to me
Describe the bug

To Reproduce
Steps to reproduce the behavior:

Expected behavior

Write a judgment to determine if the player's backpack is full so that the player does not consume resources
Screenshots

not
System (please complete the following information):

OS: Windows 10 22H2
Server software Spigot
Server Version 1.8.8
Plugin Version 23.12.2
Additional context

not