This mixin will crash minecraft if null is passed in for the player. Since player is @nullable a null check should be put in

https://github.com/Tigereye504/spellbound/blob/5e06ce7d3de953ad400e931647e0de5f51f8cbdd/src/main/java/net/tigereye/spellbound/mixins/ItemStackClientMixin.java#L22C1-L24C6

Scouter456/Enchantsmith#2 (comment)