Better nullability annotations/handling for ItemStacks

core/src/main/java/org/geysermc/geyser/inventory/GeyserItemStack.java

@@ -34,6 +34,7 @@ import lombok.Getter;
 import org.checkerframework.checker.nullness.qual.NonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.cloudburstmc.protocol.bedrock.data.inventory.ItemData;
+import org.geysermc.geyser.item.Items;
 import org.geysermc.geyser.item.type.Item;
 import org.geysermc.geyser.registry.Registries;
 import org.geysermc.geyser.registry.type.ItemMapping;
@@ -42,7 +43,7 @@ import org.geysermc.geyser.translator.inventory.item.ItemTranslator;
 
 @Data
 public class GeyserItemStack {
-    public static final GeyserItemStack EMPTY = new GeyserItemStack(0, 0, null);
+    public static final GeyserItemStack EMPTY = new GeyserItemStack(Items.AIR_ID, 0, null);
 
     private final int javaId;
     private int amount;
@@ -64,7 +65,7 @@ public class GeyserItemStack {
         this.netId = netId;
     }
 
-    public static @NonNull GeyserItemStack from(ItemStack itemStack) {
+    public static @NonNull GeyserItemStack from(@Nullable ItemStack itemStack) {
         return itemStack == null ? EMPTY : new GeyserItemStack(itemStack.getId(), itemStack.getAmount(), itemStack.getNbt());
     }
 
@@ -122,7 +123,7 @@ public class GeyserItemStack {
     }
 
     public boolean isEmpty() {
-        return amount <= 0 || javaId == 0;
+        return amount <= 0 || javaId == Items.AIR_ID;
     }
 
     public GeyserItemStack copy() {

core/src/main/java/org/geysermc/geyser/inventory/recipe/GeyserShapedRecipe.java

@@ -28,8 +28,9 @@ package org.geysermc.geyser.inventory.recipe;
 import com.github.steveice10.mc.protocol.data.game.entity.metadata.ItemStack;
 import com.github.steveice10.mc.protocol.data.game.recipe.Ingredient;
 import com.github.steveice10.mc.protocol.data.game.recipe.data.ShapedRecipeData;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
-public record GeyserShapedRecipe(int width, int height, Ingredient[] ingredients, ItemStack result) implements GeyserRecipe {
+public record GeyserShapedRecipe(int width, int height, Ingredient[] ingredients, @Nullable ItemStack result) implements GeyserRecipe {
 
     public GeyserShapedRecipe(ShapedRecipeData data) {
         this(data.getWidth(), data.getHeight(), data.getIngredients(), data.getResult());

core/src/main/java/org/geysermc/geyser/inventory/recipe/GeyserShapelessRecipe.java

@@ -28,8 +28,9 @@ package org.geysermc.geyser.inventory.recipe;
 import com.github.steveice10.mc.protocol.data.game.entity.metadata.ItemStack;
 import com.github.steveice10.mc.protocol.data.game.recipe.Ingredient;
 import com.github.steveice10.mc.protocol.data.game.recipe.data.ShapelessRecipeData;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
-public record GeyserShapelessRecipe(Ingredient[] ingredients, ItemStack result) implements GeyserRecipe {
+public record GeyserShapelessRecipe(Ingredient[] ingredients, @Nullable ItemStack result) implements GeyserRecipe {
 
     public GeyserShapelessRecipe(ShapelessRecipeData data) {
         this(data.getIngredients(), data.getResult());

core/src/main/java/org/geysermc/geyser/inventory/recipe/GeyserStonecutterData.java

@@ -26,10 +26,11 @@
 package org.geysermc.geyser.inventory.recipe;
 
 import com.github.steveice10.mc.protocol.data.game.entity.metadata.ItemStack;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
  * @param buttonId the button that needs to be pressed for Java Edition to accept this item.
  * @param output the expected output of this item when cut.
  */
-public record GeyserStonecutterData(int buttonId, ItemStack output) {
+public record GeyserStonecutterData(int buttonId, @Nullable ItemStack output) {
 }

core/src/main/java/org/geysermc/geyser/item/Items.java

@@ -1351,6 +1351,8 @@ public final class Items {
     public static final Item TRIAL_SPAWNER = register(new BlockItem("trial_spawner", builder()));
     public static final Item TRIAL_KEY = register(new Item("trial_key", builder()));
 
+    public static final int AIR_ID = AIR.javaId();
+
     private static <T extends Item> T register(T item) {
         return register(item, Registries.JAVA_ITEMS.get().size());
     }

core/src/main/java/org/geysermc/geyser/item/type/Item.java

@@ -40,6 +40,7 @@ import org.geysermc.geyser.text.ChatColor;
 import org.geysermc.geyser.text.MinecraftLocale;
 import org.geysermc.geyser.translator.inventory.item.ItemTranslator;
 import org.geysermc.geyser.translator.text.MessageTranslator;
+import org.geysermc.geyser.util.InventoryUtils;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -82,7 +83,7 @@ public class Item {
     /* Translation methods to Bedrock and back */
 
     public ItemData.Builder translateToBedrock(ItemStack itemStack, ItemMapping mapping, ItemMappings mappings) {
-        if (itemStack == null) {
+        if (InventoryUtils.isEmpty(itemStack)) {
             // Return, essentially, air
             return ItemData.builder();
         }

core/src/main/java/org/geysermc/geyser/registry/type/ItemMappings.java

@@ -83,7 +83,7 @@ public class ItemMappings implements DefinitionRegistry<ItemDefinition> {
      * @return an item entry from the given java edition identifier
      */
     @NonNull
-    public ItemMapping getMapping(ItemStack itemStack) {
+    public ItemMapping getMapping(@NonNull ItemStack itemStack) {
         return this.getMapping(itemStack.getId());
     }
 

core/src/main/java/org/geysermc/geyser/translator/inventory/item/ItemTranslator.java

@@ -67,6 +67,7 @@ import org.geysermc.geyser.registry.Registries;
 import org.geysermc.geyser.text.ChatColor;
 import org.geysermc.geyser.text.MinecraftLocale;
 import org.geysermc.geyser.translator.text.MessageTranslator;
+import org.geysermc.geyser.util.InventoryUtils;
 
 import java.text.DecimalFormat;
 import java.util.*;
@@ -89,7 +90,7 @@ public final class ItemTranslator {
      */
     public static ItemStack translateToJava(ItemData data, ItemMappings mappings) {
         if (data == null) {
-            return new ItemStack(0);
+            return new ItemStack(Items.AIR_ID);
         }
 
         ItemMapping bedrockItem = mappings.getMapping(data);
@@ -118,7 +119,7 @@ public final class ItemTranslator {
 
     @NonNull
     public static ItemData translateToBedrock(GeyserSession session, ItemStack stack) {
-        if (stack == null) {
+        if (InventoryUtils.isEmpty(stack)) {
             return ItemData.AIR;
         }
 

core/src/main/java/org/geysermc/geyser/translator/protocol/bedrock/BedrockBlockPickRequestTranslator.java

@@ -56,7 +56,7 @@ public class BedrockBlockPickRequestTranslator extends PacketTranslator<BlockPic
             ItemFrameEntity entity = ItemFrameEntity.getItemFrameEntity(session, packet.getBlockPosition());
             if (entity != null) {
                 // Check to see if the item frame has an item in it first
-                if (entity.getHeldItem() != null && entity.getHeldItem().getId() != 0) {
+                if (!InventoryUtils.isEmpty(entity.getHeldItem())) {
                     // Grab the item in the frame
                     InventoryUtils.findOrCreateItem(session, entity.getHeldItem());
                 } else {

core/src/main/java/org/geysermc/geyser/translator/protocol/java/inventory/JavaContainerSetSlotTranslator.java

@@ -118,7 +118,7 @@ public class JavaContainerSetSlotTranslator extends PacketTranslator<Clientbound
             return;
         }
 
-        if (item == null || item.getId() == 0) {
+        if (InventoryUtils.isEmpty(item)) {
             return;
         }
 

core/src/main/java/org/geysermc/geyser/translator/protocol/java/inventory/JavaMerchantOffersTranslator.java

@@ -44,6 +44,7 @@ import org.geysermc.geyser.session.GeyserSession;
 import org.geysermc.geyser.translator.inventory.item.ItemTranslator;
 import org.geysermc.geyser.translator.protocol.PacketTranslator;
 import org.geysermc.geyser.translator.protocol.Translator;
+import org.geysermc.geyser.util.InventoryUtils;
 import org.geysermc.geyser.util.MathUtils;
 
 import java.util.ArrayList;
@@ -158,14 +159,14 @@ public class JavaMerchantOffersTranslator extends PacketTranslator<ClientboundMe
     }
 
     private static NbtMap getItemTag(GeyserSession session, ItemStack stack) {
-        if (stack == null || stack.getAmount() <= 0) { // Negative item counts appear as air on Java
+        if (InventoryUtils.isEmpty(stack)) { // Negative item counts appear as air on Java
             return NbtMap.EMPTY;
         }
         return getItemTag(session, stack, session.getItemMappings().getMapping(stack), stack.getAmount());
     }
 
     private static NbtMap getItemTag(GeyserSession session, ItemStack stack, int specialPrice, int demand, float priceMultiplier) {
-        if (stack == null || stack.getAmount() <= 0) { // Negative item counts appear as air on Java
+        if (InventoryUtils.isEmpty(stack)) { // Negative item counts appear as air on Java
             return NbtMap.EMPTY;
         }
         ItemMapping mapping = session.getItemMappings().getMapping(stack);

core/src/main/java/org/geysermc/geyser/util/InventoryUtils.java

@@ -61,6 +61,7 @@ import org.geysermc.geyser.text.GeyserLocale;
 import org.geysermc.geyser.translator.inventory.InventoryTranslator;
 import org.geysermc.geyser.translator.inventory.LecternInventoryTranslator;
 import org.geysermc.geyser.translator.inventory.chest.DoubleChestInventoryTranslator;
+import org.jetbrains.annotations.Contract;
 
 import java.util.Arrays;
 import java.util.Collections;
@@ -181,8 +182,9 @@ public class InventoryUtils {
     /**
      * Checks to see if an item stack represents air or has no count.
      */
+    @Contract("null -> true")
     public static boolean isEmpty(@Nullable ItemStack itemStack) {
-        return itemStack == null || itemStack.getId() == Items.AIR.javaId() || itemStack.getAmount() <= 0;
+        return itemStack == null || itemStack.getId() == Items.AIR_ID || itemStack.getAmount() <= 0;
     }
 
     /**
@@ -233,11 +235,10 @@ public class InventoryUtils {
      * @param itemStack the item to try to find a match for. NBT will also be accounted for.
      */
     public static void findOrCreateItem(GeyserSession session, ItemStack itemStack) {
-        PlayerInventory inventory = session.getPlayerInventory();
+        if (isEmpty(itemStack)) {
-
-        if (itemStack == null || itemStack.getId() == 0) {
             return;
         }
+        PlayerInventory inventory = session.getPlayerInventory();
 
         // Check hotbar for item
         for (int i = 36; i < 45; i++) {

gradle/libs.versions.toml

@@ -14,7 +14,7 @@ protocol-connection = "3.0.0.Beta1-20231107.190703-112"
 raknet = "1.0.0.CR1-20230703.195238-9"
 blockstateupdater="1.20.50-20231106.161340-1"
 mcauthlib = "d9d773e"
-mcprotocollib = "00bce42"
+mcprotocollib = "c6ba2fa"
 adventure = "4.14.0"
 adventure-platform = "4.3.0"
 junit = "5.9.2"