Entity Lifespan API

fabric-item-api-v1/src/main/java/net/fabricmc/fabric/api/item/v1/FabricItem.java

@@ -18,12 +18,15 @@
 
 import net.minecraft.component.type.AttributeModifiersComponent;
 import net.minecraft.enchantment.Enchantment;
+import net.minecraft.entity.ItemEntity;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.Hand;
+import net.minecraft.world.World;
 
 import net.fabricmc.fabric.impl.item.FabricItemInternals;
+import net.fabricmc.fabric.mixin.item.ItemEntityAccessor;
 
 /**
  * General-purpose Fabric-provided extensions for {@link Item} subclasses.
@@ -119,15 +122,29 @@ default ItemStack getRecipeRemainder(ItemStack stack) {
 	 * <p>Note that this method is only called <em>after</em> the {@link EnchantmentEvents#ALLOW_ENCHANTING} event, and
 	 * only if none of the listeners to that event override the result.</p>
 	 *
-	 * @param stack the current stack
+	 * @param stack       the current stack
 	 * @param enchantment the enchantment to check
-	 * @param context the context in which the enchantment is being checked
+	 * @param context     the context in which the enchantment is being checked
 	 * @return whether the enchantment is allowed to apply to the stack
 	 */
 	default boolean canBeEnchantedWith(ItemStack stack, Enchantment enchantment, EnchantingContext context) {
 		return enchantment.isAcceptableItem(stack);
 	}
 
+	/**
+	 * Retrieves the {@link ItemEntityAccessor#getDespawnAge() default spawn age} of 6000 ticks or 5 minutes of this item when it is dropped on the ground
+	 * as an {@link ItemEntity}.
+	 * <p>
+	 * This is in ticks.
+	 *
+	 * @param stack the current {@link ItemStack}
+	 * @param world the world the entity is in
+	 * @return the normal lifespan in ticks
+	 */
+	default int getEntityLifespan(ItemStack stack, ItemEntity entity, World world) {
+		return ItemEntityAccessor.getDespawnAge();
+	}
+
 	/**
 	 * Fabric-provided extensions for {@link Item.Settings}.
 	 * This interface is automatically implemented on all item settings via Mixin and interface injection.

fabric-item-api-v1/src/main/java/net/fabricmc/fabric/api/item/v1/FabricItemStack.java

@@ -17,8 +17,10 @@
 package net.fabricmc.fabric.api.item.v1;
 
 import net.minecraft.enchantment.Enchantment;
+import net.minecraft.entity.ItemEntity;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
+import net.minecraft.world.World;
 
 import net.fabricmc.fabric.api.util.TriState;
 
@@ -47,7 +49,7 @@ default ItemStack getRecipeRemainder() {
 	 * {@link Enchantment#isAcceptableItem(ItemStack)}</p>
 	 *
 	 * @param enchantment the enchantment to check
-	 * @param context the context in which the enchantment is being checked
+	 * @param context     the context in which the enchantment is being checked
 	 * @return whether the enchantment is allowed to apply to the stack
 	 * @see FabricItem#canBeEnchantedWith(ItemStack, Enchantment, EnchantingContext)
 	 */
@@ -59,4 +61,15 @@ default boolean canBeEnchantedWith(Enchantment enchantment, EnchantingContext co
 		);
 		return result.orElseGet(() -> ((ItemStack) this).getItem().canBeEnchantedWith((ItemStack) this, enchantment, context));
 	}
+
+	/**
+	 * Retrieves the normal 'lifespan' of this item when it is dropped on the ground
+	 * as an {@link net.minecraft.entity.ItemEntity}. This is in ticks. The standard result is 6000 ticks, or 5 minutes.
+	 *
+	 * @param world the world the entity is in
+	 * @return the normal lifespan in ticks
+	 */
+	default int getEntityLifespan(ItemEntity entity, World world) {
+		return ((ItemStack) this).getItem().getEntityLifespan(((ItemStack) this), entity, world);
+	}
 }

fabric-item-api-v1/src/main/java/net/fabricmc/fabric/mixin/item/ItemEntityAccessor.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.fabric.mixin.item;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.gen.Accessor;
+
+import net.minecraft.entity.ItemEntity;
+
+@Mixin(ItemEntity.class)
+public interface ItemEntityAccessor {
+	@Accessor("DESPAWN_AGE")
+	static int getDespawnAge() {
+		throw new AssertionError();
+	}
+}

fabric-item-api-v1/src/main/java/net/fabricmc/fabric/mixin/item/ItemEntityMixin.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.fabric.mixin.item;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import net.minecraft.entity.Entity;
+import net.minecraft.entity.EntityType;
+import net.minecraft.entity.ItemEntity;
+import net.minecraft.item.ItemStack;
+import net.minecraft.world.World;
+
+@Mixin(ItemEntity.class)
+public abstract class ItemEntityMixin extends Entity {
+
+	@Shadow
+	private int itemAge;
+
+	private ItemEntityMixin(EntityType<?> type, World world) {
+		super(type, world);
+	}
+
+	@Inject(at = @At("TAIL"), method = "setDespawnImmediately")
+	private void modifyDespawnImmediately(CallbackInfo ci) {
+		this.itemAge = getStack().getEntityLifespan((ItemEntity) ((Entity) this), this.getWorld());
+	}
+
+	@Shadow
+	abstract ItemStack getStack();
+}

fabric-item-api-v1/src/main/resources/fabric-item-api-v1.mixins.json

@@ -9,6 +9,8 @@
     "EnchantCommandMixin",
     "EnchantmentHelperMixin",
     "EnchantRandomlyLootFunctionMixin",
+    "ItemEntityAccessor",
+    "ItemEntityMixin",
     "ItemAccessor",
     "ItemMixin",
     "ItemSettingsMixin",

gradle.properties

@@ -60,4 +60,4 @@ fabric-transfer-api-v1-version=5.1.6
 fabric-transitive-access-wideners-v1-version=6.0.10
 fabric-convention-tags-v1-version=2.0.4
 fabric-convention-tags-v2-version=2.1.0
-fabric-client-tags-api-v1-version=1.1.12
+fabric-client-tags-api-v1-version=1.1.12