[1.20.6] Add GatherItemComponentsEvent

patches/minecraft/net/minecraft/world/item/Item.java.patch

@@ -23,7 +23,26 @@
      }
 
      @Deprecated
-@@ -111,6 +_,7 @@
+@@ -100,17 +_,25 @@
+         return this.builtInRegistryHolder;
+     }
+
++    @Nullable
++    private DataComponentMap builtComponents = null;
++
+     public DataComponentMap components() {
+-        return this.components;
++        if (builtComponents == null) {
++            builtComponents = net.minecraftforge.common.ForgeHooks.gatherItemComponents(this, components);
++        }
++        return builtComponents;
+     }
+
+     public int getDefaultMaxStackSize() {
++        if (builtComponents != null) return this.builtComponents.getOrDefault(DataComponents.MAX_STACK_SIZE, 1);
+         return this.components.getOrDefault(DataComponents.MAX_STACK_SIZE, 1);
+     }
+
      public void onUseTick(Level p_41428_, LivingEntity p_41429_, ItemStack p_41430_, int p_41431_) {
      }
 

src/main/java/net/minecraftforge/common/ForgeHooks.java

@@ -49,6 +49,7 @@
 import net.minecraft.core.HolderLookup;
 import net.minecraft.core.HolderSet;
 import net.minecraft.core.NonNullList;
+import net.minecraft.core.component.DataComponentMap;
 import net.minecraft.core.component.DataComponents;
 import net.minecraft.core.particles.ParticleTypes;
 import net.minecraft.network.Connection;
@@ -114,7 +115,6 @@
 import net.minecraft.world.level.biome.MobSpawnSettings;
 import net.minecraftforge.common.crafting.conditions.ConditionCodec;
 import net.minecraftforge.common.crafting.conditions.ICondition;
-import net.minecraftforge.common.crafting.conditions.ICondition.IContext;
 import net.minecraftforge.common.crafting.ingredients.IIngredientSerializer;
 import net.minecraftforge.common.util.BlockSnapshot;
 import net.minecraftforge.common.util.BrainBuilder;
@@ -1261,4 +1261,8 @@ public static StreamCodec<RegistryFriendlyByteBuf, Ingredient> ingredientStreamC
             }
         );
     }
+
+    public static DataComponentMap gatherItemComponents(Item item, DataComponentMap dataComponents) {
+        return DataComponentMap.composite(dataComponents, ForgeEventFactory.gatherItemComponentsEvent(item, dataComponents).getDataComponentMap());
+    }
 }

src/main/java/net/minecraftforge/event/ForgeEventFactory.java

@@ -13,6 +13,8 @@
 import java.util.function.BooleanSupplier;
 import java.util.function.Consumer;
 
+import net.minecraft.core.component.DataComponentMap;
+import net.minecraft.world.item.Item;
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -1060,4 +1062,8 @@ public static AnvilRepairEvent onAnvilRepair(Player player, @NotNull ItemStack o
     public static void onPlayerTradeWithVillager(Player player, MerchantOffer offer, AbstractVillager villager) {
         post(new TradeWithVillagerEvent(player, offer, villager));
     }
+
+    public static GatherComponentsEvent.GatherItemComponentsEvent gatherItemComponentsEvent(Item item, DataComponentMap dataComponents) {
+        return fire(new GatherComponentsEvent.GatherItemComponentsEvent(item, dataComponents));
+    }
 }

src/main/java/net/minecraftforge/event/GatherComponentsEvent.java

@@ -0,0 +1,45 @@
+package net.minecraftforge.event;
+
+import net.minecraft.core.component.DataComponentMap;
+import net.minecraft.core.component.DataComponentType;
+import net.minecraft.world.item.Item;
+import net.minecraftforge.eventbus.api.Event;
+import org.jetbrains.annotations.ApiStatus;
+
+import javax.annotation.Nullable;
+
+/**
+ Where all the events fore Gathering Components will exist.
+ */
+
+public abstract class GatherComponentsEvent extends Event {
+    private final DataComponentMap.Builder components = DataComponentMap.builder();
+
+    public <T> void register(DataComponentType<T> componentType, @Nullable T value) {
+        components.set(componentType, value);
+    }
+
+    @ApiStatus.Internal
+    public DataComponentMap getDataComponentMap() {
+        return components.build();
+    }
+
+
+    public static class GatherItemComponentsEvent extends GatherComponentsEvent {
+        private final Item item;
+        private final DataComponentMap dataComponents;
+
+        public GatherItemComponentsEvent(Item item, DataComponentMap dataComponents) {
+            this.item = item;
+            this.dataComponents = dataComponents;
+        }
+
+        public Item getItem() {
+            return item;
+        }
+
+        public DataComponentMap getDataComponentMap() {
+            return dataComponents;
+        }
+    }
+}