ItemStack serialization is lossy

[ItsDoot]

In the following snippet, myItemB does not have the unbreakable tag, nor any enchantments.

ItemStack myItemA = ItemStack.builder()
            .itemType(ItemTypes.NETHERITE_HELMET)
            .add(Keys.IS_UNBREAKABLE, true)
            .add(Keys.APPLIED_ENCHANTMENTS, List.of(Enchantment.of(EnchantmentTypes.PROTECTION, 3)))
            .build();
ItemStackSnapshot mySnapshot = myItemA.createSnapshot();
ItemStack myItemB = mySnapshot.createStack();

[ItsDoot]

Tested with:

final ItemStack itemA = ItemStack.builder()
        .itemType(ItemTypes.NETHERITE_HELMET)
        .add(Keys.IS_UNBREAKABLE, true)
        .add(Keys.APPLIED_ENCHANTMENTS, List.of(Enchantment.of(EnchantmentTypes.PROTECTION, 3)))
        .build();
final ItemStackSnapshot itemSnapshot = itemA.createSnapshot();
final ItemStack itemB = itemSnapshot.createStack();

this.logger.info("itemA: " + itemA.getValues());
this.logger.info("itemSnapshot: " + itemSnapshot.getValues());
this.logger.info("itemB: " + itemB.getValues());

Outputting:

[16:55:25] [Server thread/INFO] [kitpvp]: itemA: [ImmutableSpongeValue{key=sponge:is_unbreakable, element=true}, ImmutableSpongeListValue{key=sponge:applied_enchantments, element=[SpongeEnchantment[enchantmentType=EnchantmentType{Name=enchantment.minecraft.protection, Key=minecraft:protection}, level=3]]}]
[16:55:25] [Server thread/INFO] [kitpvp]: itemSnapshot: []
[16:55:25] [Server thread/INFO] [kitpvp]: itemB: [ImmutableSpongeValue{key=sponge:is_unbreakable, element=true}, ImmutableSpongeListValue{key=sponge:applied_enchantments, element=[SpongeEnchantment[enchantmentType=EnchantmentType{Name=enchantment.minecraft.protection, Key=minecraft:protection}, level=3]]}]

So it seems like the conversion itself transfers values fine, but when we call player.equip(EquipmentTypes.HEAD, itemB), the data is not serialized correctly, as the client doesn't see the enchantments on the item, nor that the item is unbreakable.