So i met the bug in a pretty simple code, and I completely don't know why it appears.

https://youtu.be/9o534kIYxUc

I want to create Gift item, that after putting it with another item in crafting, it makes it enchanted. And then after right clicking it, it turns into certain item.

BUT
Weird things are doing here. Item disappears or gives result WITHOUT crafting it (just putting and collecting it from crafting table menu).

My code

GiftCrafting - special recipe

Spoiler

package com.matez.wildnature.items.recipes;

import com.matez.wildnature.items.GiftItem;
import com.matez.wildnature.other.Utilities;
import net.minecraft.inventory.CraftingInventory;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.item.crafting.IRecipeSerializer;
import net.minecraft.item.crafting.SpecialRecipe;
import net.minecraft.nbt.CompoundNBT;
import net.minecraft.util.ResourceLocation;
import net.minecraft.util.registry.Registry;
import net.minecraft.world.World;

public class GiftCrafting extends SpecialRecipe {

    public GiftCrafting(ResourceLocation idIn) {
        super(idIn);
    }

    public boolean matches(CraftingInventory inv, World worldIn) {
        int i = 0;
        int j = 0;
        for(int k = 0; k < inv.getSizeInventory(); ++k) {
            ItemStack itemstack = inv.getStackInSlot(k);
            if (!itemstack.isEmpty()) {
                if (itemstack.getItem() instanceof GiftItem) {
                    if(itemstack.getOrCreateTag().isEmpty()) {
                        ++i;
                    }
                } else {
                    ++j;
                }

                if (j > 1 || i > 1) {
                    return false;
                }
            }
        }

        return i == 1 && j == 1;
    }

    public ItemStack getCraftingResult(CraftingInventory inv) {
        ItemStack giftItemStack = ItemStack.EMPTY;
        ItemStack gift = ItemStack.EMPTY;



        for(int i = 0; i < inv.getSizeInventory(); ++i) {
            ItemStack itemstack1 = inv.getStackInSlot(i);
            if (!itemstack1.isEmpty()) {
                Item item = itemstack1.getItem();
                if (item instanceof GiftItem) {
                    giftItemStack = itemstack1;
                } else {
                    gift = itemstack1;
                }
            }
        }

        ItemStack result = giftItemStack;
        CompoundNBT nbt = giftItemStack.getOrCreateTag();
        if(nbt.isEmpty() && giftItemStack != ItemStack.EMPTY && gift != ItemStack.EMPTY) {
            Utilities.saveItem(nbt, new ItemStack(gift.getItem()));
            result.setTag(nbt);
        }else{
            return null;
        }

        return result;
    }

    public boolean canFit(int width, int height) {
        return width * height >= 2;
    }


    @Override
    public IRecipeSerializer<?> getSerializer() {
        return Registry.RECIPE_SERIALIZER.getOrDefault(new ResourceLocation("wildnature:gift_crafting"));
    }
}

Gift Item class
 

Spoiler

package com.matez.wildnature.items;

import com.matez.wildnature.other.Utilities;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.item.ItemUseContext;
import net.minecraft.util.*;
import net.minecraftforge.api.distmarker.Dist;
import net.minecraftforge.api.distmarker.OnlyIn;

public class GiftItem extends Item {
    private GiftColor color;
    public GiftItem(Properties properties, GiftColor color) {
        super(properties.maxStackSize(1));
        this.color=color;
    }

    @Override
    public ActionResultType onItemUse(ItemUseContext context) {
        System.out.println("click");
        ItemStack i = context.getPlayer().getHeldItem(context.getHand());
        ItemStack gift = Utilities.loadItem(i.getTag());

        if(gift == ItemStack.EMPTY) {
            return ActionResultType.PASS;
        }else{
            context.getPlayer().setHeldItem(context.getHand(),gift);
            return ActionResultType.SUCCESS;
        }
    }

    @OnlyIn(Dist.CLIENT)
    public boolean hasEffect(ItemStack stack) {
        ItemStack gift = Utilities.loadItem(stack.getTag());
        return gift != ItemStack.EMPTY;
    }


    public enum GiftColor implements IStringSerializable {
        CYAN_RED("cyan_red"),
        RED_YELLOW("red_yellow"),
        BLUE_PINK("blue_pink");

        public static final GiftColor[] VALUES = values();
        private final String name;

        private GiftColor(String name) {
            this.name = name;
        }

        @Override
        public String getName() {
            return null;
        }
    }

}

Special Recipe Registry
  

Spoiler

@SubscribeEvent
public static void registerRecipes(final RegistryEvent.Register<IRecipeSerializer<?>> event){
    LOGGER.info("Registering recipes...");
    event.getRegistry().register(new SpecialRecipeSerializer<>(GiftCrafting::new).setRegistryName("wildnature:gift_crafting"));
}

 

 

This makes no sense but works. Thanks !