Added 1.21.6 support

Fix FabledSkyBlock errors on new versions of the plugin

.github/workflows/java-ci.yml

@@ -21,7 +21,7 @@ jobs:
           java-version: 21
 
       - name: Setup build cache
-        uses: actions/cache@v2.1.6
+        uses: actions/cache@v4
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle.kts') }}
@@ -30,7 +30,7 @@ jobs:
 
       - run: ./gradlew build --full-stacktrace
 
-      - uses: actions/upload-artifact@v2
-        with:
-          name: eco-dev-${{ steps.vars.outputs.sha_short }}
-          path: build/libs
+#      - uses: actions/upload-artifact@v2
+#        with:
+#          name: eco-dev-${{ steps.vars.outputs.sha_short }}
+#          path: build/libs

.github/workflows/publish-release.yml

@@ -19,7 +19,7 @@ jobs:
           java-version: 21
 
       - name: Setup build cache
-        uses: actions/cache@v2.1.6
+        uses: actions/cache@v4
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle.kts') }}

.gitignore

@@ -21,4 +21,7 @@ bin/
 gradle-app.setting
 
 # Mac OSX
-.DS_Store
+.DS_Store
+
+# Kotlin
+.kotlin

build.gradle.kts

@@ -1,20 +1,21 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
 buildscript {
     repositories {
         mavenCentral()
     }
 
     dependencies {
-        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.21")
+        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:2.1.0")
     }
 }
 
 plugins {
     id("java-library")
-    id("io.github.goooler.shadow") version "8.1.7"
+    id("com.gradleup.shadow") version "8.3.5"
     id("maven-publish")
     id("java")
-    kotlin("jvm") version "1.9.21"
-    kotlin("plugin.serialization") version "1.9.21"
+    kotlin("jvm") version "2.1.0"
 }
 
 dependencies {
@@ -33,23 +34,31 @@ dependencies {
     implementation(project(path = ":eco-core:core-nms:v1_20_R2", configuration = "reobf"))
     implementation(project(path = ":eco-core:core-nms:v1_20_R3", configuration = "reobf"))
     implementation(project(path = ":eco-core:core-nms:v1_21", configuration = "reobf"))
+    implementation(project(path = ":eco-core:core-nms:v1_21_3", configuration = "reobf"))
+    implementation(project(path = ":eco-core:core-nms:v1_21_4", configuration = "reobf"))
+    implementation(project(path = ":eco-core:core-nms:v1_21_5", configuration = "reobf"))
+    implementation(project(path = ":eco-core:core-nms:v1_21_6", configuration = "reobf"))
 }
 
 allprojects {
     apply(plugin = "java")
     apply(plugin = "java-library")
     apply(plugin = "maven-publish")
-    apply(plugin = "io.github.goooler.shadow")
+    apply(plugin = "com.gradleup.shadow")
     apply(plugin = "kotlin")
-    apply(plugin = "org.jetbrains.kotlin.plugin.serialization")
 
     repositories {
         mavenCentral()
+
         maven("https://repo.auxilor.io/repository/maven-public/")
+
         maven("https://jitpack.io") {
             content { includeGroupByRegex("com\\.github\\..*") }
         }
 
+        // Paper
+        maven("https://repo.papermc.io/repository/maven-public/")
+
         // SuperiorSkyblock2
         maven("https://repo.bg-software.com/repository/api/")
 
@@ -63,7 +72,7 @@ allprojects {
         maven("https://repo.extendedclip.com/content/repositories/placeholderapi/")
 
         // ProtocolLib
-        //maven("https://repo.dmulloy2.net/nexus/repository/public/")
+        maven("https://repo.dmulloy2.net/nexus/repository/public/")
 
         // WorldGuard
         maven("https://maven.enginehub.org/repo/")
@@ -104,12 +113,12 @@ allprojects {
 
     dependencies {
         // Kotlin
-        implementation(kotlin("stdlib", version = "1.9.21"))
+        implementation(kotlin("stdlib", version = "2.1.0"))
         implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.7.3")
 
         // Included in spigot jar, no need to move to implementation
         compileOnly("org.jetbrains:annotations:23.0.0")
-        compileOnly("com.google.guava:guava:31.1-jre")
+        compileOnly("com.google.guava:guava:32.0.0-jre")
 
         // Test
         testImplementation("org.junit.jupiter:junit-jupiter-api:5.9.2")
@@ -153,8 +162,8 @@ allprojects {
         }
 
         compileKotlin {
-            kotlinOptions {
-                jvmTarget = "17"
+            compilerOptions {
+                jvmTarget.set(JvmTarget.JVM_17)
             }
         }
 
@@ -177,14 +186,14 @@ allprojects {
         }
 
         withType<JavaCompile>().configureEach {
-            options.release = 17
+            options.release.set(17)
         }
     }
 
     java {
         withSourcesJar()
         toolchain {
-            languageVersion = JavaLanguageVersion.of(21)
+            languageVersion.set(JavaLanguageVersion.of(21))
         }
     }
 }
@@ -212,7 +221,6 @@ tasks {
         //relocate("com.mysql", "com.willfp.eco.libs.mysql")
         relocate("com.mongodb", "com.willfp.eco.libs.mongodb")
         relocate("org.bson", "com.willfp.eco.libs.bson")
-        relocate("org.litote", "com.willfp.eco.libs.litote")
         relocate("org.reactivestreams", "com.willfp.eco.libs.reactivestreams")
         relocate("reactor.", "com.willfp.eco.libs.reactor.") // Dot in name to be safe
         relocate("com.moandjiezana.toml", "com.willfp.eco.libs.toml")
@@ -226,4 +234,4 @@ tasks {
 }
 
 group = "com.willfp"
-version = findProperty("version")!!
+version = findProperty("version")!!

eco-api/src/main/java/com/willfp/eco/core/EcoPlugin.java

@@ -37,8 +37,6 @@ import org.jetbrains.annotations.Nullable;
 import java.io.File;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Objects;

eco-api/src/main/java/com/willfp/eco/core/Prerequisite.java

@@ -38,15 +38,23 @@ public class Prerequisite {
     );
 
     /**
-     * Requires the server to be running 1.21.
+     * Requires the server to be running at least 1.21.3.
+     */
+    public static final Prerequisite HAS_1_21_3 = new Prerequisite(
+            () -> ProxyConstants.NMS_VERSION.contains("1_21_3"),
+            "Requires server to be running 1.21.3+"
+    );
+
+    /**
+     * Requires the server to be running at least 1.21.
      */
     public static final Prerequisite HAS_1_21 = new Prerequisite(
-            () -> ProxyConstants.NMS_VERSION.contains("1_21"),
+            () -> ProxyConstants.NMS_VERSION.contains("1_21") || HAS_1_21_3.isMet(),
             "Requires server to be running 1.21+"
     );
 
     /**
-     * Requires the server to be running 1.20.5.
+     * Requires the server to be running at least 1.20.5.
      */
     public static final Prerequisite HAS_1_20_5 = new Prerequisite(
             () -> (ProxyConstants.NMS_VERSION.contains("1_20_") && !ProxyConstants.NMS_VERSION.contains("R"))
@@ -55,7 +63,7 @@ public class Prerequisite {
     );
 
     /**
-     * Requires the server to be running 1.20.3.
+     * Requires the server to be running at least 1.20.3.
      */
     public static final Prerequisite HAS_1_20_3 = new Prerequisite(
             () -> ProxyConstants.NMS_VERSION.contains("20_R3") || HAS_1_20_5.isMet(),
@@ -63,7 +71,7 @@ public class Prerequisite {
     );
 
     /**
-     * Requires the server to be running 1.20.
+     * Requires the server to be running at least 1.20.
      */
     public static final Prerequisite HAS_1_20 = new Prerequisite(
             () -> ProxyConstants.NMS_VERSION.contains("20") || HAS_1_20_3.isMet(),
@@ -71,7 +79,7 @@ public class Prerequisite {
     );
 
     /**
-     * Requires the server to be running 1.19.4.
+     * Requires the server to be running at least 1.19.4.
      */
     public static final Prerequisite HAS_1_19_4 = new Prerequisite(
             () -> ProxyConstants.NMS_VERSION.contains("19_R3") || HAS_1_20.isMet(),
@@ -79,7 +87,7 @@ public class Prerequisite {
     );
 
     /**
-     * Requires the server to be running 1.19.
+     * Requires the server to be running at least 1.19.
      */
     public static final Prerequisite HAS_1_19 = new Prerequisite(
             () -> ProxyConstants.NMS_VERSION.contains("19") || HAS_1_20.isMet(),
@@ -87,7 +95,7 @@ public class Prerequisite {
     );
 
     /**
-     * Requires the server to be running 1.18.
+     * Requires the server to be running at least 1.18.
      */
     public static final Prerequisite HAS_1_18 = new Prerequisite(
             () -> ProxyConstants.NMS_VERSION.contains("18") || HAS_1_19.isMet(),

eco-api/src/main/java/com/willfp/eco/core/data/handlers/DataTypeSerializer.java

@@ -0,0 +1,44 @@
+package com.willfp.eco.core.data.handlers;
+
+import com.willfp.eco.core.data.keys.PersistentDataKey;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.UUID;
+
+/**
+ * Handles data read/write for a {@link com.willfp.eco.core.data.keys.PersistentDataKeyType} for a specific
+ * data handler.
+ *
+ * @param <T> The type of data.
+ */
+public abstract class DataTypeSerializer<T> {
+    /**
+     * Create a new data type serializer.
+     */
+    protected DataTypeSerializer() {
+
+    }
+
+    /**
+     * Read a value.
+     *
+     * @param uuid The uuid.
+     * @param key  The key.
+     * @return The value.
+     */
+    @Nullable
+    public abstract T readAsync(@NotNull final UUID uuid,
+                                @NotNull final PersistentDataKey<T> key);
+
+    /**
+     * Write a value.
+     *
+     * @param uuid  The uuid.
+     * @param key   The key.
+     * @param value The value.
+     */
+    public abstract void writeAsync(@NotNull final UUID uuid,
+                                    @NotNull final PersistentDataKey<T> key,
+                                    @NotNull final T value);
+}

eco-api/src/main/java/com/willfp/eco/core/data/handlers/PersistentDataHandler.java

@@ -0,0 +1,179 @@
+package com.willfp.eco.core.data.handlers;
+
+import com.willfp.eco.core.data.keys.PersistentDataKey;
+import com.willfp.eco.core.registry.Registrable;
+import com.willfp.eco.core.tuples.Pair;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+/**
+ * Handles persistent data.
+ */
+public abstract class PersistentDataHandler implements Registrable {
+    /**
+     * The id.
+     */
+    private final String id;
+
+    /**
+     * The executor.
+     */
+    private final ExecutorService executor = Executors.newCachedThreadPool();
+
+    /**
+     * Create a new persistent data handler.
+     *
+     * @param id The id.
+     */
+    protected PersistentDataHandler(@NotNull final String id) {
+        this.id = id;
+    }
+
+    /**
+     * Get all UUIDs with saved data.
+     * <p>
+     * This is a blocking operation.
+     *
+     * @return All saved UUIDs.
+     */
+    public abstract Set<UUID> getSavedUUIDs();
+
+    /**
+     * Save to disk.
+     * <p>
+     * If write commits to disk, this method does not need to be overridden.
+     * <p>
+     * This method is called asynchronously.
+     */
+    protected void doSave() {
+        // Save to disk
+    }
+
+    /**
+     * If the handler should autosave.
+     *
+     * @return If the handler should autosave.
+     */
+    public boolean shouldAutosave() {
+        return true;
+    }
+
+    /**
+     * Save the data.
+     */
+    public final void save() {
+        executor.submit(this::doSave);
+    }
+
+    /**
+     * Read a key from persistent data.
+     *
+     * @param uuid The uuid.
+     * @param key  The key.
+     * @param <T>  The type of the key.
+     * @return The value, or null if not found.
+     */
+    @Nullable
+    public final <T> T read(@NotNull final UUID uuid,
+                            @NotNull final PersistentDataKey<T> key) {
+        DataTypeSerializer<T> serializer = key.getType().getSerializer(this);
+        Future<T> future = executor.submit(() -> serializer.readAsync(uuid, key));
+
+        try {
+            return future.get();
+        } catch (InterruptedException | ExecutionException e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
+
+    /**
+     * Write a key to persistent data.
+     *
+     * @param uuid  The uuid.
+     * @param key   The key.
+     * @param value The value.
+     * @param <T>   The type of the key.
+     */
+    public final <T> void write(@NotNull final UUID uuid,
+                                @NotNull final PersistentDataKey<T> key,
+                                @NotNull final T value) {
+        DataTypeSerializer<T> serializer = key.getType().getSerializer(this);
+        executor.submit(() -> serializer.writeAsync(uuid, key, value));
+    }
+
+    /**
+     * Serialize profile.
+     *
+     * @param uuid The uuid to serialize.
+     * @param keys The keys to serialize.
+     * @return The serialized data.
+     */
+    @NotNull
+    public final SerializedProfile serializeProfile(@NotNull final UUID uuid,
+                                                    @NotNull final Set<PersistentDataKey<?>> keys) {
+        Map<PersistentDataKey<?>, CompletableFuture<Object>> futures = keys.stream()
+                .collect(Collectors.toMap(
+                        key -> key,
+                        key -> CompletableFuture.supplyAsync(() -> read(uuid, key), executor)
+                ));
+
+        Map<PersistentDataKey<?>, Object> data = futures.entrySet().stream()
+                .map(entry -> new Pair<PersistentDataKey<?>, Object>(entry.getKey(), entry.getValue().join()))
+                .filter(entry -> entry.getSecond() != null)
+                .collect(Collectors.toMap(Pair::getFirst, Pair::getSecond));
+
+        return new SerializedProfile(uuid, data);
+    }
+
+    /**`
+     * Load profile data.
+     *
+     * @param profile The profile.
+     */
+    @SuppressWarnings("unchecked")
+    public final void loadSerializedProfile(@NotNull final SerializedProfile profile) {
+        for (Map.Entry<PersistentDataKey<?>, Object> entry : profile.data().entrySet()) {
+            PersistentDataKey<?> key = entry.getKey();
+            Object value = entry.getValue();
+
+            // This cast is safe because the data is serialized
+            write(profile.uuid(), (PersistentDataKey<? super Object>) key, value);
+        }
+    }
+
+    /**
+     * Save and shutdown the handler.
+     *
+     * @throws InterruptedException If the writes could not be awaited.
+     */
+    public final void shutdown() throws InterruptedException {
+        doSave();
+
+        if (executor.isShutdown()) {
+            return;
+        }
+
+        executor.shutdown();
+        while (!executor.awaitTermination(2, TimeUnit.MINUTES)) {
+            // Wait
+        }
+    }
+
+    @Override
+    @NotNull
+    public final String getID() {
+        return id;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/data/handlers/SerializedProfile.java

@@ -0,0 +1,20 @@
+package com.willfp.eco.core.data.handlers;
+
+import com.willfp.eco.core.data.keys.PersistentDataKey;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Map;
+import java.util.UUID;
+
+/**
+ * Serialized profile.
+ *
+ * @param uuid The uuid.
+ * @param data The data.
+ */
+public record SerializedProfile(
+        @NotNull UUID uuid,
+        @NotNull Map<PersistentDataKey<?>, Object> data
+) {
+
+}

eco-api/src/main/java/com/willfp/eco/core/data/keys/PersistentDataKey.java

@@ -34,6 +34,19 @@ public final class PersistentDataKey<T> {
      */
     private final boolean isLocal;
 
+    /**
+     * Create a new Persistent Data Key.
+     *
+     * @param key          The key.
+     * @param type         The data type.
+     * @param defaultValue The default value.
+     */
+    public PersistentDataKey(@NotNull final NamespacedKey key,
+                             @NotNull final PersistentDataKeyType<T> type,
+                             @NotNull final T defaultValue) {
+        this(key, type, defaultValue, false);
+    }
+
     /**
      * Create a new Persistent Data Key.
      *
@@ -54,24 +67,6 @@ public final class PersistentDataKey<T> {
         Eco.get().registerPersistentKey(this);
     }
 
-    /**
-     * Create a new Persistent Data Key.
-     *
-     * @param key          The key.
-     * @param type         The data type.
-     * @param defaultValue The default value.
-     */
-    public PersistentDataKey(@NotNull final NamespacedKey key,
-                             @NotNull final PersistentDataKeyType<T> type,
-                             @NotNull final T defaultValue) {
-        this.key = key;
-        this.defaultValue = defaultValue;
-        this.type = type;
-        this.isLocal = false;
-
-        Eco.get().registerPersistentKey(this);
-    }
-
     @Override
     public String toString() {
         return "PersistentDataKey{"

eco-api/src/main/java/com/willfp/eco/core/data/keys/PersistentDataKeyType.java

@@ -1,12 +1,17 @@
 package com.willfp.eco.core.data.keys;
 
 import com.willfp.eco.core.config.interfaces.Config;
+import com.willfp.eco.core.data.handlers.DataTypeSerializer;
+import com.willfp.eco.core.data.handlers.PersistentDataHandler;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.math.BigDecimal;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
+import java.util.NoSuchElementException;
 import java.util.Objects;
 
 /**
@@ -61,18 +66,14 @@ public final class PersistentDataKeyType<T> {
     private final String name;
 
     /**
-     * Get the name of the key type.
-     *
-     * @return The name.
+     * The serializers for this key type.
      */
-    public String name() {
-        return name;
-    }
+    private final Map<PersistentDataHandler, DataTypeSerializer<T>> serializers = new HashMap<>();
 
     /**
      * Create new PersistentDataKeyType.
      *
-     * @param name      The name.
+     * @param name The name.
      */
     private PersistentDataKeyType(@NotNull final String name) {
         VALUES.add(this);
@@ -80,6 +81,44 @@ public final class PersistentDataKeyType<T> {
         this.name = name;
     }
 
+    /**
+     * Get the name of the key type.
+     *
+     * @return The name.
+     */
+    @NotNull
+    public String name() {
+        return name;
+    }
+
+    /**
+     * Register a serializer for this key type.
+     *
+     * @param handler    The handler.
+     * @param serializer The serializer.
+     */
+    public void registerSerializer(@NotNull final PersistentDataHandler handler,
+                                   @NotNull final DataTypeSerializer<T> serializer) {
+        this.serializers.put(handler, serializer);
+    }
+
+    /**
+     * Get the serializer for a handler.
+     *
+     * @param handler The handler.
+     * @return The serializer.
+     */
+    @NotNull
+    public DataTypeSerializer<T> getSerializer(@NotNull final PersistentDataHandler handler) {
+        DataTypeSerializer<T> serializer = this.serializers.get(handler);
+
+        if (serializer == null) {
+            throw new NoSuchElementException("No serializer for handler: " + handler);
+        }
+
+        return serializer;
+    }
+
     @Override
     public boolean equals(@Nullable final Object that) {
         if (this == that) {

eco-api/src/main/java/com/willfp/eco/core/entities/Entities.java

@@ -111,6 +111,11 @@ public final class Entities {
             } catch (IllegalArgumentException e) {
                 return new EmptyTestableEntity();
             }
+
+            if (type.getEntityClass() == null) {
+                return new EmptyTestableEntity();
+            }
+
             entity = new SimpleTestableEntity(type);
         } else {
             String namespace = split[0];

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalUseItem.java

@@ -6,6 +6,7 @@ import com.willfp.eco.core.entities.TestableEntity;
 import com.willfp.eco.core.entities.ai.EntityGoal;
 import com.willfp.eco.core.items.Items;
 import com.willfp.eco.core.serialization.KeyedDeserializer;
+import com.willfp.eco.util.SoundUtils;
 import org.bukkit.NamespacedKey;
 import org.bukkit.Sound;
 import org.bukkit.entity.LivingEntity;
@@ -50,9 +51,15 @@ public record EntityGoalUseItem(
 
             TestableEntity filter = Entities.lookup(config.getString("condition"));
 
+            Sound sound = SoundUtils.getSound(config.getString("sound"));
+
+            if (sound == null) {
+                return null;
+            }
+
             return new EntityGoalUseItem(
                     Items.lookup(config.getString("item")).getItem(),
-                    Sound.valueOf(config.getString("sound").toUpperCase()),
+                    sound,
                     filter::matches
             );
         }

eco-api/src/main/java/com/willfp/eco/core/entities/ai/target/TargetGoalNearestAttackable.java

@@ -11,19 +11,21 @@ import org.bukkit.entity.Raider;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.util.Set;
 import java.util.function.Predicate;
+import java.util.stream.Collectors;
 
 /**
  * Allows an entity to attack the closest target within a given subset of specific target types.
  *
- * @param target           The type of entities to attack.
+ * @param targets          The type of entities to attack.
  * @param checkVisibility  If visibility should be checked.
  * @param checkCanNavigate If navigation should be checked.
  * @param reciprocalChance 1 in reciprocalChance chance of not activating on any tick.
  * @param targetFilter     The filter for targets to match.
  */
 public record TargetGoalNearestAttackable(
-        @NotNull TestableEntity target,
+        @NotNull Set<TestableEntity> targets,
         boolean checkVisibility,
         boolean checkCanNavigate,
         int reciprocalChance,
@@ -32,16 +34,16 @@ public record TargetGoalNearestAttackable(
     /**
      * Create a new target goal.
      *
-     * @param target           The type of entities to attack.
+     * @param targets          The type of entities to attack.
      * @param checkVisibility  If visibility should be checked.
      * @param checkCanNavigate If navigation should be checked.
      * @param reciprocalChance 1 in reciprocalChance chance of not activating on any tick.
      */
-    public TargetGoalNearestAttackable(@NotNull final TestableEntity target,
+    public TargetGoalNearestAttackable(@NotNull final Set<TestableEntity> targets,
                                        final boolean checkVisibility,
                                        final boolean checkCanNavigate,
                                        final int reciprocalChance) {
-        this(target, checkVisibility, checkCanNavigate, reciprocalChance, it -> true);
+        this(targets, checkVisibility, checkCanNavigate, reciprocalChance, it -> true);
     }
 
     /**
@@ -65,11 +67,15 @@ public record TargetGoalNearestAttackable(
                 return null;
             }
 
+            Set<TestableEntity> targets = config.getStrings("target").stream()
+                    .map(Entities::lookup)
+                    .collect(Collectors.toSet());
+
             if (config.has("targetFilter")) {
                 TestableEntity filter = Entities.lookup(config.getString("targetFilter"));
 
                 return new TargetGoalNearestAttackable(
-                        Entities.lookup(config.getString("target")),
+                        targets,
                         config.getBool("checkVisibility"),
                         config.getBool("checkCanNavigate"),
                         config.getInt("reciprocalChance"),
@@ -77,7 +83,7 @@ public record TargetGoalNearestAttackable(
                 );
             } else {
                 return new TargetGoalNearestAttackable(
-                        Entities.lookup(config.getString("target")),
+                        targets,
                         config.getBool("checkVisibility"),
                         config.getBool("checkCanNavigate"),
                         config.getInt("reciprocalChance")

eco-api/src/main/java/com/willfp/eco/core/integrations/antigrief/AntigriefManager.java

@@ -7,9 +7,6 @@ import org.bukkit.entity.LivingEntity;
 import org.bukkit.entity.Player;
 import org.jetbrains.annotations.NotNull;
 
-import java.util.HashSet;
-import java.util.Set;
-
 /**
  * Class to handle antigrief integrations.
  */

eco-api/src/main/java/com/willfp/eco/core/integrations/customitems/CustomItemsManager.java

@@ -3,9 +3,6 @@ package com.willfp.eco.core.integrations.customitems;
 import com.willfp.eco.core.integrations.IntegrationRegistry;
 import org.jetbrains.annotations.NotNull;
 
-import java.util.HashSet;
-import java.util.Set;
-
 /**
  * Class to handle custom item integrations.
  */

eco-api/src/main/java/com/willfp/eco/core/integrations/mcmmo/McmmoManager.java

@@ -5,9 +5,6 @@ import org.bukkit.block.Block;
 import org.bukkit.event.Event;
 import org.jetbrains.annotations.NotNull;
 
-import java.util.HashSet;
-import java.util.Set;
-
 /**
  * Class to handle mcmmo integrations.
  */

eco-api/src/main/java/com/willfp/eco/core/items/Items.java

@@ -6,6 +6,7 @@ import com.willfp.eco.core.Eco;
 import com.willfp.eco.core.fast.FastItemStack;
 import com.willfp.eco.core.items.args.LookupArgParser;
 import com.willfp.eco.core.items.provider.ItemProvider;
+import com.willfp.eco.core.items.tag.ItemTag;
 import com.willfp.eco.core.recipe.parts.EmptyTestableItem;
 import com.willfp.eco.core.recipe.parts.MaterialTestableItem;
 import com.willfp.eco.core.recipe.parts.ModifiedTestableItem;
@@ -13,7 +14,6 @@ import com.willfp.eco.core.recipe.parts.TestableStack;
 import com.willfp.eco.core.recipe.parts.UnrestrictedMaterialTestableItem;
 import com.willfp.eco.util.NamespacedKeyUtils;
 import com.willfp.eco.util.NumberUtils;
-import kotlin.Suppress;
 import org.bukkit.Material;
 import org.bukkit.NamespacedKey;
 import org.bukkit.enchantments.Enchantment;
@@ -93,6 +93,11 @@ public final class Items {
      */
     private static final Map<String, Material> FRIENDLY_MATERIAL_NAMES = new HashMap<>();
 
+    /**
+     * All tags.
+     */
+    private static final Map<String, ItemTag> TAGS = new HashMap<>();
+
     /**
      * Register a new custom item.
      *
@@ -217,7 +222,20 @@ public final class Items {
 
         String[] split = args[0].toLowerCase().split(":");
 
-        if (split.length == 1) {
+        String base = split[0];
+        boolean isTag = base.startsWith("#");
+
+        if (isTag) {
+            String tag = base.substring(1);
+            ItemTag itemTag = TAGS.get(tag);
+
+            if (itemTag == null) {
+                return new EmptyTestableItem();
+            }
+            item = itemTag.toTestableItem();
+        }
+
+        if (split.length == 1 && !isTag) {
             String itemType = args[0];
             boolean isWildcard = itemType.startsWith("*");
             if (isWildcard) {
@@ -230,7 +248,7 @@ public final class Items {
             item = isWildcard ? new UnrestrictedMaterialTestableItem(material) : new MaterialTestableItem(material);
         }
 
-        if (split.length == 2) {
+        if (split.length == 2 && !isTag) {
             String namespace = split[0];
             String keyID = split[1];
             NamespacedKey namespacedKey = NamespacedKeyUtils.create(namespace, keyID);
@@ -274,7 +292,7 @@ public final class Items {
         Legacy namespace:id:amount format
         This has been superseded by namespace:id amount
          */
-        if (split.length == 3) {
+        if (split.length == 3 && !isTag) {
             TestableItem part = REGISTRY.get(NamespacedKeyUtils.create(split[0], split[1]));
             if (part == null) {
                 return new EmptyTestableItem();
@@ -306,7 +324,8 @@ public final class Items {
 
         List<Predicate<ItemStack>> predicates = new ArrayList<>();
 
-        for (LookupArgParser argParser : ARG_PARSERS) {
+        for (
+                LookupArgParser argParser : ARG_PARSERS) {
             Predicate<ItemStack> predicate = argParser.parseArguments(modifierArgs, meta);
             if (predicate != null) {
                 predicates.add(argParser.parseArguments(modifierArgs, meta));
@@ -611,6 +630,24 @@ public final class Items {
         return false;
     }
 
+    /**
+     * Register a new item tag.
+     *
+     * @param tag The tag.
+     */
+    public static void registerTag(@NotNull final ItemTag tag) {
+        TAGS.put(tag.getIdentifier(), tag);
+    }
+
+    /**
+     * Get all tags.
+     *
+     * @return All tags.
+     */
+    public static Collection<ItemTag> getTags() {
+        return TAGS.values();
+    }
+
     private Items() {
         throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
     }

eco-api/src/main/java/com/willfp/eco/core/items/tag/CustomItemTag.java

@@ -0,0 +1,29 @@
+package com.willfp.eco.core.items.tag;
+
+import org.bukkit.NamespacedKey;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A custom item tag.
+ */
+public abstract class CustomItemTag implements ItemTag {
+    /**
+     * The key.
+     */
+    private final NamespacedKey key;
+
+    /**
+     * Create a new custom item tag.
+     *
+     * @param key         The key.
+     */
+    public CustomItemTag(@NotNull final NamespacedKey key) {
+        this.key = key;
+    }
+
+    @Override
+    @NotNull
+    public String getIdentifier() {
+        return key.toString();
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/items/tag/ItemTag.java

@@ -0,0 +1,66 @@
+package com.willfp.eco.core.items.tag;
+
+import com.willfp.eco.core.items.TestableItem;
+import org.bukkit.Material;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * A group of items that share a common trait.
+ */
+public interface ItemTag {
+    /**
+     * Get the identifier of the tag.
+     *
+     * @return The identifier.
+     */
+    @NotNull
+    String getIdentifier();
+
+    /**
+     * Check if an item matches the tag.
+     *
+     * @param itemStack The item to check.
+     * @return If the item matches the tag.
+     */
+    boolean matches(@NotNull ItemStack itemStack);
+
+    /**
+     * Get an example item.
+     *
+     * @return The example item.
+     */
+    @Nullable
+    default ItemStack getExampleItem() {
+        return null;
+    }
+
+    /**
+     * Convert this tag to a testable item.
+     *
+     * @return The testable item.
+     */
+    @NotNull
+    default TestableItem toTestableItem() {
+        return new TestableItem() {
+            @Override
+            public boolean matches(@Nullable final ItemStack itemStack) {
+                return itemStack != null && ItemTag.this.matches(itemStack);
+            }
+
+            @Override
+            public @NotNull ItemStack getItem() {
+                ItemStack example = ItemTag.this.getExampleItem();
+                return example == null ? new ItemStack(Material.STONE) : example;
+            }
+
+            @Override
+            public String toString() {
+                return "ItemTagTestableItem{" +
+                        "tag=" + ItemTag.this.getIdentifier() +
+                        '}';
+            }
+        };
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/items/tag/VanillaItemTag.java

@@ -0,0 +1,58 @@
+package com.willfp.eco.core.items.tag;
+
+import org.bukkit.Material;
+import org.bukkit.Tag;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A vanilla item tag.
+ */
+public final class VanillaItemTag implements ItemTag {
+    /**
+     * The identifier.
+     */
+    private final String identifier;
+
+    /**
+     * The tag.
+     */
+    private final Tag<Material> tag;
+
+    /**
+     * Create a new vanilla item tag.
+     *
+     * @param identifier The identifier.
+     * @param tag        The tag.
+     */
+    public VanillaItemTag(@NotNull final String identifier,
+                          @NotNull final Tag<Material> tag) {
+        this.identifier = identifier;
+        this.tag = tag;
+    }
+
+    /**
+     * Get the tag.
+     *
+     * @return The tag.
+     */
+    public Tag<Material> getTag() {
+        return tag;
+    }
+
+    @Override
+    @NotNull
+    public String getIdentifier() {
+        return identifier;
+    }
+
+    @Override
+    public boolean matches(@NotNull final ItemStack itemStack) {
+        return tag.isTagged(itemStack.getType());
+    }
+
+    @Override
+    public @NotNull ItemStack getExampleItem() {
+        return new ItemStack(tag.getValues().stream().findFirst().orElse(Material.STONE));
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/packet/Packet.java

@@ -6,10 +6,51 @@ import org.jetbrains.annotations.NotNull;
 
 /**
  * Represents a packet.
- *
- * @param handle The NMS handle.
  */
-public record Packet(@NotNull Object handle) {
+public class Packet {
+    /**
+     * The packet handle.
+     */
+    private Object handle;
+
+    /**
+     * Create a new packet.
+     *
+     * @param handle The packet handle.
+     */
+    public Packet(@NotNull final Object handle) {
+        this.handle = handle;
+    }
+
+    /**
+     * Get the packet handle.
+     *
+     * @return The packet handle.
+     */
+    public Object getHandle() {
+        return handle;
+    }
+
+    /**
+     * Set the packet handle.
+     *
+     * @param handle The packet handle.
+     */
+    public void setHandle(@NotNull final Object handle) {
+        this.handle = handle;
+    }
+
+    /**
+     * Get the packet handle, compatible with the old record-based packet system.
+     *
+     * @return The packet handle.
+     * @deprecated Use {@link #getHandle()} instead.
+     */
+    @Deprecated
+    public Object handle() {
+        return handle;
+    }
+
     /**
      * Send to a player.
      *

eco-api/src/main/java/com/willfp/eco/core/proxy/ProxyConstants.java

@@ -2,6 +2,7 @@ package com.willfp.eco.core.proxy;
 
 import com.willfp.eco.core.version.Version;
 import org.bukkit.Bukkit;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.Arrays;
 import java.util.List;
@@ -28,13 +29,25 @@ public final class ProxyConstants {
             "v1_20_R1",
             "v1_20_R2",
             "v1_20_R3",
-            "v1_21"
+            "v1_21",
+            "v1_21_3",
+            "v1_21_4",
+            "v1_21_5",
+            "v1_21_6"
     );
 
     private ProxyConstants() {
         throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
     }
 
+    private static String convertVersion(@NotNull final String version) {
+        return switch (version) {
+            case "v1_21_1" -> "v1_21";
+            case "v1_21_2" -> "v1_21_3";
+            default -> version;
+        };
+    }
+
     static {
         String currentMinecraftVersion = Bukkit.getServer().getBukkitVersion().split("-")[0];
         String nmsVersion;
@@ -45,6 +58,6 @@ public final class ProxyConstants {
             nmsVersion = "v" + currentMinecraftVersion.replace(".", "_");
         }
 
-        NMS_VERSION = nmsVersion;
+        NMS_VERSION = convertVersion(nmsVersion);
     }
 }

eco-api/src/main/java/com/willfp/eco/core/sound/PlayableSound.java

@@ -2,6 +2,7 @@ package com.willfp.eco.core.sound;
 
 import com.willfp.eco.core.config.interfaces.Config;
 import com.willfp.eco.core.serialization.ConfigDeserializer;
+import com.willfp.eco.util.SoundUtils;
 import org.bukkit.Location;
 import org.bukkit.Sound;
 import org.bukkit.World;
@@ -82,20 +83,20 @@ public record PlayableSound(@NotNull Sound sound,
                 return null;
             }
 
-            try {
-                Sound sound = Sound.valueOf(config.getString("sound").toUpperCase());
+            Sound sound = SoundUtils.getSound(config.getString("sound"));
 
-                double pitch = Objects.requireNonNullElse(config.getDoubleOrNull("pitch"), 1.0);
-                double volume = Objects.requireNonNullElse(config.getDoubleOrNull("volume"), 1.0);
-
-                return new PlayableSound(
-                        sound,
-                        pitch,
-                        volume
-                );
-            } catch (IllegalArgumentException e) {
+            if (sound == null) {
                 return null;
             }
+
+            double pitch = Objects.requireNonNullElse(config.getDoubleOrNull("pitch"), 1.0);
+            double volume = Objects.requireNonNullElse(config.getDoubleOrNull("volume"), 1.0);
+
+            return new PlayableSound(
+                    sound,
+                    pitch,
+                    volume
+            );
         }
     }
 }

eco-api/src/main/java/com/willfp/eco/util/SoundUtils.java

@@ -0,0 +1,50 @@
+package com.willfp.eco.util;
+
+import com.willfp.eco.core.Prerequisite;
+import org.bukkit.NamespacedKey;
+import org.bukkit.Registry;
+import org.bukkit.Sound;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.lang.reflect.Field;
+
+/**
+ * Utilities / API methods for sounds.
+ */
+public final class SoundUtils {
+    /**
+     * Get a sound in a version-compatible way.
+     *
+     * @param name The name of the sound, case-insensitive.
+     * @return The sound, or null if not found.
+     */
+    @Nullable
+    public static Sound getSound(@NotNull final String name) {
+        if (!Prerequisite.HAS_1_21_3.isMet()) {
+            try {
+                return Sound.valueOf(name.toUpperCase());
+            } catch (IllegalArgumentException e) {
+                return null;
+            }
+        }
+
+        // First try from registry (preferred)
+        Sound fromRegistry = Registry.SOUNDS.get(NamespacedKey.minecraft(name.toLowerCase()));
+        if (fromRegistry != null) {
+            return fromRegistry;
+        }
+
+        // Next try using reflection (for legacy enum names)
+        try {
+            Field field = Sound.class.getDeclaredField(name.toUpperCase());
+            return (Sound) field.get(null);
+        } catch (ReflectiveOperationException e) {
+            return null;
+        }
+    }
+
+    private SoundUtils() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+}

eco-core/core-backend-modern/build.gradle.kts

@@ -1,19 +1,21 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
 group = "com.willfp"
 version = rootProject.version
 
 dependencies {
     compileOnly(project(":eco-core:core-backend"))
-    compileOnly("io.papermc.paper:paper-api:1.21-R0.1-SNAPSHOT")
+    compileOnly("io.papermc.paper:paper-api:1.21.1-R0.1-SNAPSHOT")
 }
 
 tasks {
     compileJava {
-        options.release = 21
+        options.release.set(21)
     }
 
     compileKotlin {
-        kotlinOptions {
-            jvmTarget = "21"
+        compilerOptions {
+            jvmTarget.set(JvmTarget.JVM_21)
         }
     }
 }

eco-core/core-backend-modern/src/main/kotlin/com/willfp/eco/internal/compat/modern/entities/parsers/EntityArgParserScale.kt

@@ -4,8 +4,6 @@ import com.willfp.eco.core.entities.args.EntityArgParseResult
 import com.willfp.eco.core.entities.args.EntityArgParser
 import org.bukkit.attribute.Attribute
 import org.bukkit.entity.LivingEntity
-import org.bukkit.entity.Phantom
-import org.bukkit.entity.Slime
 
 object EntityArgParserScale : EntityArgParser {
     override fun parseArguments(args: Array<out String>): EntityArgParseResult? {

eco-core/core-backend/build.gradle.kts

@@ -1,3 +1,5 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
 group = "com.willfp"
 version = rootProject.version
 
@@ -7,7 +9,7 @@ dependencies {
     implementation("org.objenesis:objenesis:3.2")
 
     compileOnly("io.papermc.paper:paper-api:1.20.2-R0.1-SNAPSHOT")
-    compileOnly("me.clip:placeholderapi:2.11.4")
+    compileOnly("me.clip:placeholderapi:2.11.6")
     compileOnly("net.kyori:adventure-text-minimessage:4.10.0")
     compileOnly("net.kyori:adventure-platform-bukkit:4.1.0")
     compileOnly("org.yaml:snakeyaml:1.33")
@@ -16,12 +18,12 @@ dependencies {
 
 tasks {
     compileJava {
-        options.release = 17
+        options.release.set(17)
     }
 
     compileKotlin {
-        kotlinOptions {
-            jvmTarget = "17"
+        compilerOptions {
+            jvmTarget.set(JvmTarget.JVM_17)
         }
     }
 }

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/events/EcoEventManager.kt

@@ -9,7 +9,6 @@ import com.willfp.eco.core.packet.PacketPriority
 import org.bukkit.Bukkit
 import org.bukkit.event.HandlerList
 import org.bukkit.event.Listener
-import java.lang.Exception
 
 
 private class RegisteredPacketListener(
@@ -80,9 +79,11 @@ class EcoEventManager(private val plugin: EcoPlugin) : EventManager {
     }
 
     override fun registerPacketListener(listener: PacketListener) {
-        listeners[listener.priority] += RegisteredPacketListener(
-            plugin,
-            listener
+        listeners[listener.priority].add(
+            RegisteredPacketListener(
+                plugin,
+                listener
+            )
         )
     }
 }

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/gui/slot/EcoSlotBuilder.kt

@@ -23,7 +23,7 @@ class EcoSlotBuilder(private val provider: SlotProvider) : SlotBuilder {
     private var notCaptiveFor: (Player) -> Boolean = { _ -> false}
 
     override fun onClick(type: ClickType, action: SlotHandler): SlotBuilder {
-        handlers[type] += action
+        handlers[type].add(action)
         return this
     }
 

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/items/ArgParserCustomModelData.kt

@@ -7,20 +7,12 @@ import java.util.function.Predicate
 
 object ArgParserCustomModelData : LookupArgParser {
     override fun parseArguments(args: Array<out String>, meta: ItemMeta): Predicate<ItemStack>? {
-        var modelData: Int? = null
+        val arg = args.firstOrNull {
+            it.startsWith("custom-model-data:", ignoreCase = true)
+                    || it.startsWith("custom_model_data:", ignoreCase = true)
+        } ?: return null
 
-        for (arg in args) {
-            val argSplit = arg.split(":")
-            if (!argSplit[0].equals("custom-model-data", ignoreCase = true)) {
-                continue
-            }
-            if (argSplit.size < 2) {
-                continue
-            }
-            modelData = argSplit[1].toIntOrNull()
-        }
-
-        modelData ?: return null
+        val modelData = arg.split(":")[1].toIntOrNull() ?: return null
 
         meta.setCustomModelData(modelData)
 
@@ -40,6 +32,6 @@ object ArgParserCustomModelData : LookupArgParser {
             return null
         }
 
-        return "custom-model-data:${meta.customModelData}"
+        return "custom_model_data:${meta.customModelData}"
     }
 }

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/items/ArgParserEnchantment.kt

@@ -2,7 +2,7 @@ package com.willfp.eco.internal.items
 
 import com.willfp.eco.core.fast.fast
 import com.willfp.eco.core.items.args.LookupArgParser
-import com.willfp.eco.util.NamespacedKeyUtils
+import org.bukkit.NamespacedKey
 import org.bukkit.enchantments.Enchantment
 import org.bukkit.inventory.ItemStack
 import org.bukkit.inventory.meta.EnchantmentStorageMeta
@@ -14,18 +14,15 @@ object ArgParserEnchantment : LookupArgParser {
         val enchants = mutableMapOf<Enchantment, Int>()
 
         for (arg in args) {
-            val argSplit = arg.split(":")
+            try {
+                val argSplit = arg.split(":")
 
-            if (argSplit.size < 2) {
-                continue
-            }
+                val enchant = Enchantment.getByKey(NamespacedKey.minecraft(argSplit[0].lowercase())) ?: continue
+                val level = argSplit.getOrNull(1)?.toIntOrNull() ?: enchant.maxLevel
 
-            @Suppress("DEPRECATION")
-            val enchant = Enchantment.getByKey(NamespacedKeyUtils.create("minecraft", argSplit[0]))
-            val level = argSplit[1].toIntOrNull()
-
-            if (enchant != null && level != null) {
                 enchants[enchant] = level
+            } catch (e: IllegalArgumentException) {
+                continue
             }
         }
 

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/items/ArgParserName.kt

@@ -2,9 +2,7 @@ package com.willfp.eco.internal.items
 
 import com.willfp.eco.internal.items.templates.ValueArgParser
 import com.willfp.eco.util.StringUtils
-import org.bukkit.inventory.ItemStack
 import org.bukkit.inventory.meta.ItemMeta
-import java.util.function.Predicate
 
 object ArgParserName : ValueArgParser<String>("name") {
     override fun parse(arg: String): String {

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/items/tags/VanillaItemTags.kt

@@ -0,0 +1,39 @@
+package com.willfp.eco.internal.items.tags
+
+import com.willfp.eco.core.items.Items
+import com.willfp.eco.core.items.tag.VanillaItemTag
+import org.bukkit.Keyed
+import org.bukkit.Material
+import org.bukkit.Tag
+
+object VanillaItemTags {
+    fun register() {
+        // Get all tags
+        val allTags = Tag::class.java.declaredFields
+            .filter { it.type == Tag::class.java }
+            .mapNotNull {
+                val tag = it.get(null) as? Tag<*>
+                if (tag == null) {
+                    null
+                } else {
+                    NamedTag(it.name.lowercase(), tag)
+                }
+            }
+
+        // Register all tags
+        for (tag in allTags) {
+            if (tag.isMaterial) {
+                Items.registerTag(
+                    @Suppress("UNCHECKED_CAST")
+                    VanillaItemTag(tag.name, tag.tag as Tag<Material>)
+                )
+            }
+        }
+    }
+
+    private data class NamedTag<T : Keyed>(val name: String, val tag: Tag<T>) {
+        // Check if tag is material
+        val isMaterial: Boolean
+            get() = tag.values.firstOrNull() is Material
+    }
+}

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/items/templates/ValueArgParser.kt

@@ -1,7 +1,6 @@
 package com.willfp.eco.internal.items.templates
 
 import com.willfp.eco.core.items.args.LookupArgParser
-import com.willfp.eco.util.StringUtils
 import org.bukkit.inventory.ItemStack
 import org.bukkit.inventory.meta.ItemMeta
 import java.util.function.Predicate

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/proxy/EcoProxyFactory.kt

@@ -50,8 +50,7 @@ class EcoProxyFactory(
             )
         } else {
             ProxyError(
-                "Could not initialize proxy. If you're seeing this error message"
-                        + ", something has gone badly wrong. This almost definitely isn't user error, blame the developer.",
+                "Could not initialize proxy. Are you running a supported server version?",
                 e
             )
         }

eco-core/core-nms/build.gradle.kts

@@ -1,5 +1,5 @@
 plugins {
-    id("io.papermc.paperweight.userdev") version "1.7.1" apply false
+    id("io.papermc.paperweight.userdev") version "2.0.0-beta.17" apply false
 }
 
 

eco-core/core-nms/common/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/Skull.kt

@@ -48,7 +48,7 @@ var SkullMeta.texture: String?
         * at java.lang.String.checkBoundsBeginEnd(String.java:4604) ~[?:?]
         * at java.lang.String.substring(String.java:2707) ~[?:?]
         * at java.lang.String.substring(String.java:2680) ~[?:?]
-        * at com.willfp.eco.internal.spigot.proxy.v1_19_R1.common.SkullKt.setTexture(Skull.kt:36)
+        * at com.willfp.eco.internal.spigot.proxy.v1_19_R1.common.SkullKt.setTexture(ModernSkull.kt:36)
         *
         if (base64.length < 20) {
             return

eco-core/core-nms/common/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/ai/EcoEntityController.kt

@@ -54,8 +54,6 @@ class EcoEntityController<T : Mob>(
             priority, goal.getGoalFactory()?.create(goal, nms) ?: return this
         )
 
-        nms.targetSelector
-
         return this
     }
 

eco-core/core-nms/common/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/ai/entity/RangedBowAttackGoalFactory.kt

@@ -10,7 +10,7 @@ import net.minecraft.world.entity.monster.RangedAttackMob
 
 object RangedBowAttackGoalFactory : EntityGoalFactory<EntityGoalRangedBowAttack> {
     override fun create(apiGoal: EntityGoalRangedBowAttack, entity: PathfinderMob): Goal? {
-        (if (entity !is Monster) return null)
+        if (entity !is Monster) return null
         if (entity !is RangedAttackMob) return null
 
         return RangedBowAttackGoal(

eco-core/core-nms/common/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/ai/entity/RangedCrossbowAttackGoalFactory.kt

@@ -11,7 +11,7 @@ import net.minecraft.world.entity.monster.RangedAttackMob
 
 object RangedCrossbowAttackGoalFactory : EntityGoalFactory<EntityGoalRangedCrossbowAttack> {
     override fun create(apiGoal: EntityGoalRangedCrossbowAttack, entity: PathfinderMob): Goal? {
-        (if (entity !is Monster) return null)
+        if (entity !is Monster) return null
         if (entity !is RangedAttackMob) return null
         if (entity !is CrossbowAttackMob) return null
 

eco-core/core-nms/common/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/ai/target/NearestAttackableGoalFactory.kt

@@ -17,7 +17,9 @@ object NearestAttackableGoalFactory : TargetGoalFactory<TargetGoalNearestAttacka
             apiGoal.checkVisibility,
             apiGoal.checkCanNavigate,
         ) {
-            apiGoal.targetFilter.test(it.toBukkitEntity()) && apiGoal.target.matches(it.toBukkitEntity())
+            val bukkit = it.toBukkitEntity()
+
+            apiGoal.targetFilter.test(bukkit) && apiGoal.targets.any { t -> t.matches(bukkit) }
         }
     }
 

eco-core/core-nms/common/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/packet/EcoChannelDuplexHandler.kt

@@ -23,7 +23,7 @@ class EcoChannelDuplexHandler(
             event.handleReceive()
 
             if (!event.isCancelled) {
-                super.channelRead(ctx, msg)
+                super.channelRead(ctx, event.packet.handle)
             }
         } else {
             super.channelRead(ctx, msg)
@@ -39,7 +39,7 @@ class EcoChannelDuplexHandler(
             event.handleSend()
 
             if (!event.isCancelled) {
-                super.write(ctx, msg, promise)
+                super.write(ctx, event.packet.handle, promise)
             }
         } else {
             super.write(ctx, msg, promise)

eco-core/core-nms/common/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/packet/display/PacketAutoRecipe.kt

@@ -3,12 +3,19 @@ package com.willfp.eco.internal.spigot.proxy.common.packet.display
 import com.willfp.eco.core.EcoPlugin
 import com.willfp.eco.core.packet.PacketEvent
 import com.willfp.eco.core.packet.PacketListener
+import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import com.willfp.eco.util.namespacedKeyOf
 import net.minecraft.network.protocol.game.ClientboundPlaceGhostRecipePacket
 import net.minecraft.resources.ResourceLocation
 
 class PacketAutoRecipe(
     private val plugin: EcoPlugin
 ) : PacketListener {
+    private val fKey = ClientboundPlaceGhostRecipePacket::class.java
+        .declaredFields
+        .first { it.type == ResourceLocation::class.java }
+        .apply { isAccessible = true }
+
     override fun onSend(event: PacketEvent) {
         val packet = event.packet.handle as? ClientboundPlaceGhostRecipePacket ?: return
 
@@ -24,9 +31,7 @@ class PacketAutoRecipe(
             return
         }
 
-        val fKey = packet.javaClass.getDeclaredField("b")
-        fKey.isAccessible = true
         val key = fKey[packet] as ResourceLocation
-        fKey[packet] = ResourceLocation(key.namespace, key.path + "_displayed")
+        fKey[packet] = namespacedKeyOf(key.namespace, key.path + "_displayed").toResourceLocation()
     }
 }

eco-core/core-nms/common/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/packet/display/PacketWindowItems.kt

@@ -15,7 +15,7 @@ import org.bukkit.inventory.ItemStack
 import java.util.UUID
 import java.util.concurrent.ConcurrentHashMap
 
-class PacketWindowItems(
+open class PacketWindowItems(
     private val plugin: EcoPlugin
 ) : PacketListener {
     private val lastKnownWindowIDs = ConcurrentHashMap<UUID, Int>()
@@ -52,7 +52,7 @@ class PacketWindowItems(
     }
 
 
-    private fun modifyWindowItems(
+    protected fun modifyWindowItems(
         itemStacks: MutableList<ItemStack>,
         windowId: Int,
         player: Player

eco-core/core-nms/modern/build.gradle.kts

@@ -1,3 +1,5 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
 plugins {
     id("io.papermc.paperweight.userdev")
 }
@@ -7,17 +9,17 @@ version = rootProject.version
 
 dependencies {
     compileOnly(project(":eco-core:core-nms:common"))
-    paperweight.paperDevBundle("1.21-R0.1-SNAPSHOT")
+    paperweight.paperDevBundle("1.21.1-R0.1-SNAPSHOT")
 }
 
 tasks {
     compileJava {
-        options.release = 21
+        options.release.set(21)
     }
 
     compileKotlin {
-        kotlinOptions {
-            jvmTarget = "21"
+        compilerOptions {
+            jvmTarget.set(JvmTarget.JVM_21)
         }
     }
 }

eco-core/core-nms/modern/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/modern/ModernSkull.kt

@@ -0,0 +1,55 @@
+package com.willfp.eco.internal.spigot.proxy.common.modern
+
+import com.mojang.authlib.GameProfile
+import com.mojang.authlib.properties.Property
+import net.minecraft.world.item.component.ResolvableProfile
+import org.bukkit.inventory.meta.SkullMeta
+import java.lang.reflect.Field
+import java.lang.reflect.Method
+import java.util.UUID
+
+private lateinit var setProfile: Method
+private lateinit var profile: Field
+private lateinit var value: Field
+
+var SkullMeta.texture: String?
+    get() {
+        if (!::value.isInitialized) {
+            // Doing it this way because Property was changed to be a record and this is
+            // a quick hack to get around that
+            value = Property::class.java.getDeclaredField("value")
+            value.isAccessible = true
+        }
+
+        if (!::profile.isInitialized) {
+            // Assumes instance of CraftMetaSkull; package-private class so can't do manual type check
+            profile = this.javaClass.getDeclaredField("profile")
+            profile.isAccessible = true
+        }
+
+        val profile = profile[this] as ResolvableProfile? ?: return null
+        val properties = profile.properties ?: return null
+        val props = properties["textures"] ?: return null
+        val prop = props.toMutableList().firstOrNull() ?: return null
+        return value[prop] as String?
+    }
+    set(base64) {
+        if (!::setProfile.isInitialized) {
+            // Same here; that's why I can't delegate to a lazy initializer
+            setProfile = this.javaClass.getDeclaredMethod("setProfile", ResolvableProfile::class.java)
+            setProfile.isAccessible = true
+        }
+
+        if (base64 == null || base64.length < 20) {
+            setProfile.invoke(this, null)
+        } else {
+            val uuid = UUID(
+                base64.substring(base64.length - 20).hashCode().toLong(),
+                base64.substring(base64.length - 10).hashCode().toLong()
+            )
+            val profile = GameProfile(uuid, "eco")
+            profile.properties.put("textures", Property("textures", base64))
+            val resolvable = ResolvableProfile(profile)
+            setProfile.invoke(this, resolvable)
+        }
+    }

eco-core/core-nms/modern/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/modern/NewEcoFastItemStack.kt

@@ -14,8 +14,6 @@ import com.willfp.eco.util.StringUtils
 import com.willfp.eco.util.toComponent
 import com.willfp.eco.util.toLegacy
 import net.kyori.adventure.text.Component
-import net.kyori.adventure.text.format.Style
-import net.kyori.adventure.text.format.TextColor
 import net.kyori.adventure.text.format.TextDecoration
 import net.minecraft.core.component.DataComponentType
 import net.minecraft.core.component.DataComponents
@@ -23,11 +21,9 @@ import net.minecraft.core.registries.Registries
 import net.minecraft.nbt.CompoundTag
 import net.minecraft.util.Unit
 import net.minecraft.world.item.component.CustomData
-import net.minecraft.world.item.component.CustomModelData
 import net.minecraft.world.item.component.ItemLore
-import org.bukkit.Bukkit
+import net.minecraft.world.item.enchantment.ItemEnchantments
 import org.bukkit.craftbukkit.CraftRegistry
-import org.bukkit.craftbukkit.CraftServer
 import org.bukkit.craftbukkit.enchantments.CraftEnchantment
 import org.bukkit.enchantments.Enchantment
 import org.bukkit.inventory.ItemFlag
@@ -43,17 +39,17 @@ private fun Component.unstyled(): Component {
     return unstyledComponent.append(this)
 }
 
-class NewEcoFastItemStack(
-    private val bukkit: ItemStack
+open class NewEcoFastItemStack(
+    private val bukkit: ItemStack,
 ) : ImplementedFIS {
     // Cast is there because, try as I might, I can't get IntellIJ to recognise half the classes in the dev bundle
     @Suppress("USELESS_CAST")
-    private val handle = bukkit.asNMSStack() as net.minecraft.world.item.ItemStack
+    protected val handle = bukkit.asNMSStack() as net.minecraft.world.item.ItemStack
 
     private val pdc = (handle.get(DataComponents.CUSTOM_DATA)?.copyTag() ?: CompoundTag()).makePdc()
 
     override fun getEnchants(checkStored: Boolean): Map<Enchantment, Int> {
-        val enchantments = handle.get(DataComponents.ENCHANTMENTS) ?: return emptyMap()
+        val enchantments = handle.get(DataComponents.ENCHANTMENTS) ?: ItemEnchantments.EMPTY
 
         val map = mutableMapOf<Enchantment, Int>()
 
@@ -80,22 +76,17 @@ class NewEcoFastItemStack(
         enchantment: Enchantment,
         checkStored: Boolean
     ): Int {
-        val minecraft =
-            CraftRegistry.bukkitToMinecraft<Enchantment, net.minecraft.world.item.enchantment.Enchantment>(
-                enchantment
-            )
-
-        val server = Bukkit.getServer() as CraftServer
-        val access = server.server.registryAccess()
-
-        val holder = access.registryOrThrow(Registries.ENCHANTMENT).wrapAsHolder(minecraft)
+        val minecraft = CraftRegistry.bukkitToMinecraftHolder(
+            enchantment,
+            Registries.ENCHANTMENT
+        )
 
         val enchantments = handle.get(DataComponents.ENCHANTMENTS) ?: return 0
-        var level = enchantments.getLevel(holder)
+        var level = enchantments.getLevel(minecraft)
 
         if (checkStored) {
             val storedEnchantments = handle.get(DataComponents.STORED_ENCHANTMENTS) ?: return 0
-            level = max(level, storedEnchantments.getLevel(holder))
+            level = max(level, storedEnchantments.getLevel(minecraft))
         }
 
         return level
@@ -153,7 +144,7 @@ class NewEcoFastItemStack(
 
     override fun getDisplayName(): String = displayNameComponent.toLegacy()
 
-    private fun <T> net.minecraft.world.item.ItemStack.modifyComponent(
+    protected fun <T> net.minecraft.world.item.ItemStack.modifyComponent(
         component: DataComponentType<T>,
         modifier: (T) -> T
     ) {
@@ -368,19 +359,23 @@ class NewEcoFastItemStack(
 
     override fun getType(): org.bukkit.Material = handle.getItem().toMaterial()
 
+    /*
+    Custom model data doesn't work based on an integer since 1.21.3, so these methods do nothing
+     */
+
     override fun getCustomModelData(): Int? =
-        handle.get(DataComponents.CUSTOM_MODEL_DATA)?.value
+        null
 
     override fun setCustomModelData(data: Int?) {
         if (data == null) {
             handle.remove(DataComponents.CUSTOM_MODEL_DATA)
-        } else {
-            handle.set(DataComponents.CUSTOM_MODEL_DATA, CustomModelData(data))
         }
 
         apply()
     }
 
+    // END
+
     override fun equals(other: Any?): Boolean {
         if (other !is NewEcoFastItemStack) {
             return false

eco-core/core-nms/v1_17_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_17_R1/ExtendedPersistentDataContainerFactory.kt

@@ -2,7 +2,6 @@ package com.willfp.eco.internal.spigot.proxy.v1_17_R1
 
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
-import com.willfp.eco.internal.spigot.proxy.common.item.ContinuallyAppliedPersistentDataContainer
 import net.minecraft.nbt.Tag
 import org.bukkit.Material
 import org.bukkit.craftbukkit.v1_17_R1.inventory.CraftItemStack

eco-core/core-nms/v1_18_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_18_R1/ExtendedPersistentDataContainerFactory.kt

@@ -2,7 +2,6 @@ package com.willfp.eco.internal.spigot.proxy.v1_18_R1
 
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
-import com.willfp.eco.internal.spigot.proxy.common.item.ContinuallyAppliedPersistentDataContainer
 import net.minecraft.nbt.Tag
 import org.bukkit.Material
 import org.bukkit.craftbukkit.v1_18_R1.inventory.CraftItemStack

eco-core/core-nms/v1_18_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_18_R2/ExtendedPersistentDataContainerFactory.kt

@@ -2,7 +2,6 @@ package com.willfp.eco.internal.spigot.proxy.v1_18_R2
 
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
-import com.willfp.eco.internal.spigot.proxy.common.item.ContinuallyAppliedPersistentDataContainer
 import net.minecraft.nbt.Tag
 import org.bukkit.Material
 import org.bukkit.craftbukkit.v1_18_R2.inventory.CraftItemStack

eco-core/core-nms/v1_19_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R1/SNBTConverter.kt

@@ -3,7 +3,6 @@ package com.willfp.eco.internal.spigot.proxy.v1_19_R1
 import com.willfp.eco.core.items.TestableItem
 import com.willfp.eco.core.recipe.parts.EmptyTestableItem
 import com.willfp.eco.internal.spigot.proxy.SNBTConverterProxy
-import com.willfp.eco.internal.spigot.proxy.common.toMaterial
 import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.SnbtPrinterTagVisitor
 import net.minecraft.nbt.TagParser

eco-core/core-nms/v1_19_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R2/CommonsInitializer.kt

@@ -5,7 +5,6 @@ import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
 import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
 import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
 import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
-import io.netty.channel.Channel
 import net.kyori.adventure.text.Component
 import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer
 import net.minecraft.core.registries.BuiltInRegistries
@@ -13,7 +12,6 @@ import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.Tag
 import net.minecraft.resources.ResourceLocation
 import net.minecraft.server.level.ServerPlayer
-import net.minecraft.server.network.ServerGamePacketListenerImpl
 import net.minecraft.world.entity.PathfinderMob
 import net.minecraft.world.item.Item
 import org.bukkit.Bukkit

eco-core/core-nms/v1_19_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R2/ExtendedPersistentDataContainerFactory.kt

@@ -2,7 +2,6 @@ package com.willfp.eco.internal.spigot.proxy.v1_19_R2
 
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
-import com.willfp.eco.internal.spigot.proxy.common.item.ContinuallyAppliedPersistentDataContainer
 import net.minecraft.nbt.Tag
 import org.bukkit.Material
 import org.bukkit.craftbukkit.v1_19_R2.inventory.CraftItemStack

eco-core/core-nms/v1_20_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R1/DisplayName.kt

@@ -4,7 +4,6 @@ import com.willfp.eco.core.packet.Packet
 import com.willfp.eco.core.packet.sendPacket
 import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
 import com.willfp.eco.internal.spigot.proxy.common.toNMS
-import io.papermc.paper.adventure.PaperAdventure
 import net.kyori.adventure.text.Component
 import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
 import net.minecraft.network.syncher.EntityDataAccessor

eco-core/core-nms/v1_20_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R2/DisplayName.kt

@@ -4,16 +4,13 @@ import com.willfp.eco.core.packet.Packet
 import com.willfp.eco.core.packet.sendPacket
 import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
 import com.willfp.eco.internal.spigot.proxy.common.toNMS
-import io.papermc.paper.adventure.PaperAdventure
 import net.kyori.adventure.text.Component
 import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
 import net.minecraft.network.syncher.EntityDataAccessor
 import net.minecraft.network.syncher.SynchedEntityData
 import net.minecraft.world.entity.Entity
 import org.bukkit.craftbukkit.v1_20_R2.entity.CraftLivingEntity
-import org.bukkit.craftbukkit.v1_20_R2.entity.CraftMob
 import org.bukkit.entity.LivingEntity
-import org.bukkit.entity.Mob
 import org.bukkit.entity.Player
 import java.util.Optional
 

eco-core/core-nms/v1_20_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R3/DisplayName.kt

@@ -4,16 +4,13 @@ import com.willfp.eco.core.packet.Packet
 import com.willfp.eco.core.packet.sendPacket
 import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
 import com.willfp.eco.internal.spigot.proxy.common.toNMS
-import io.papermc.paper.adventure.PaperAdventure
 import net.kyori.adventure.text.Component
 import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
 import net.minecraft.network.syncher.EntityDataAccessor
 import net.minecraft.network.syncher.SynchedEntityData
 import net.minecraft.world.entity.Entity
 import org.bukkit.craftbukkit.v1_20_R3.entity.CraftLivingEntity
-import org.bukkit.craftbukkit.v1_20_R3.entity.CraftMob
 import org.bukkit.entity.LivingEntity
-import org.bukkit.entity.Mob
 import org.bukkit.entity.Player
 import java.util.Optional
 

eco-core/core-nms/v1_20_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R3/DummyEntityFactory.kt

@@ -5,7 +5,6 @@ import com.willfp.eco.internal.spigot.proxy.DummyEntityFactoryProxy
 import org.bukkit.Location
 import org.bukkit.craftbukkit.v1_20_R3.CraftWorld
 import org.bukkit.entity.Entity
-import org.bukkit.entity.EntityType
 import org.bukkit.entity.Zombie
 
 class DummyEntityFactory : DummyEntityFactoryProxy {

eco-core/core-nms/v1_20_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R3/ExtendedPersistentDataContainerFactory.kt

@@ -2,7 +2,6 @@ package com.willfp.eco.internal.spigot.proxy.v1_20_R3
 
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
-import com.willfp.eco.internal.spigot.proxy.common.item.ContinuallyAppliedPersistentDataContainer
 import net.minecraft.nbt.Tag
 import org.bukkit.Material
 import org.bukkit.craftbukkit.v1_20_R3.inventory.CraftItemStack

eco-core/core-nms/v1_21/build.gradle.kts

@@ -1,3 +1,5 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
 plugins {
     id("io.papermc.paperweight.userdev")
 }
@@ -8,7 +10,7 @@ version = rootProject.version
 dependencies {
     implementation(project(":eco-core:core-nms:modern"))
     implementation(project(":eco-core:core-nms:common"))
-    paperweight.paperDevBundle("1.21-R0.1-SNAPSHOT")
+    paperweight.paperDevBundle("1.21.1-R0.1-SNAPSHOT")
 
     implementation("net.kyori:adventure-text-minimessage:4.11.0") {
         version {
@@ -39,12 +41,12 @@ tasks {
     }
 
     compileJava {
-        options.release = 21
+        options.release.set(21)
     }
 
     compileKotlin {
-        kotlinOptions {
-            jvmTarget = "21"
+        compilerOptions {
+            jvmTarget.set(JvmTarget.JVM_21)
         }
     }
 }

eco-core/core-nms/v1_21/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21/FastItemStackFactory.kt

@@ -3,10 +3,29 @@ package com.willfp.eco.internal.spigot.proxy.v1_21
 import com.willfp.eco.core.fast.FastItemStack
 import com.willfp.eco.internal.spigot.proxy.FastItemStackFactoryProxy
 import com.willfp.eco.internal.spigot.proxy.common.modern.NewEcoFastItemStack
+import net.minecraft.core.component.DataComponents
+import net.minecraft.world.item.component.CustomModelData
 import org.bukkit.inventory.ItemStack
 
 class FastItemStackFactory : FastItemStackFactoryProxy {
     override fun create(itemStack: ItemStack): FastItemStack {
-        return NewEcoFastItemStack(itemStack)
+        return LegacyNewEcoFastItemStack(itemStack)
+    }
+
+    private class LegacyNewEcoFastItemStack(itemStack: ItemStack) :
+        NewEcoFastItemStack(itemStack) {
+
+        override fun getCustomModelData(): Int? =
+            handle.get(DataComponents.CUSTOM_MODEL_DATA)?.value
+
+        override fun setCustomModelData(data: Int?) {
+            if (data == null) {
+                handle.remove(DataComponents.CUSTOM_MODEL_DATA)
+            } else {
+                handle.set(DataComponents.CUSTOM_MODEL_DATA, CustomModelData(data))
+            }
+
+            apply()
+        }
     }
 }

eco-core/core-nms/v1_21/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21/Skull.kt

@@ -1,7 +1,7 @@
 package com.willfp.eco.internal.spigot.proxy.v1_21
 
 import com.willfp.eco.internal.spigot.proxy.SkullProxy
-import com.willfp.eco.internal.spigot.proxy.common.texture
+import com.willfp.eco.internal.spigot.proxy.common.modern.texture
 import org.bukkit.inventory.meta.SkullMeta
 
 class Skull : SkullProxy {

eco-core/core-nms/v1_21_3/build.gradle.kts

@@ -0,0 +1,52 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+plugins {
+    id("io.papermc.paperweight.userdev")
+}
+
+group = "com.willfp"
+version = rootProject.version
+
+dependencies {
+    implementation(project(":eco-core:core-nms:modern"))
+    implementation(project(":eco-core:core-nms:common"))
+    paperweight.paperDevBundle("1.21.3-R0.1-SNAPSHOT")
+
+    implementation("net.kyori:adventure-text-minimessage:4.11.0") {
+        version {
+            strictly("4.11.0")
+        }
+        exclude(group = "net.kyori", module = "adventure-api")
+    }
+}
+
+tasks {
+    build {
+        dependsOn(reobfJar)
+    }
+
+    reobfJar {
+        mustRunAfter(shadowJar)
+    }
+
+    shadowJar {
+        relocate(
+            "com.willfp.eco.internal.spigot.proxy.common",
+            "com.willfp.eco.internal.spigot.proxy.v1_21_3.common"
+        )
+        relocate(
+            "net.kyori.adventure.text.minimessage",
+            "com.willfp.eco.internal.spigot.proxy.v1_21_3.minimessage"
+        )
+    }
+
+    compileJava {
+        options.release.set(21)
+    }
+
+    compileKotlin {
+        compilerOptions {
+            jvmTarget.set(JvmTarget.JVM_21)
+        }
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/BukkitCommands.kt

@@ -0,0 +1,35 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3
+
+import com.willfp.eco.core.command.PluginCommandBase
+import com.willfp.eco.internal.spigot.proxy.BukkitCommandsProxy
+import org.bukkit.Bukkit
+import org.bukkit.command.Command
+import org.bukkit.command.SimpleCommandMap
+import org.bukkit.craftbukkit.CraftServer
+import java.lang.reflect.Field
+
+class BukkitCommands : BukkitCommandsProxy {
+    private val knownCommandsField: Field by lazy {
+        SimpleCommandMap::class.java.getDeclaredField("knownCommands")
+            .apply {
+                isAccessible = true
+            }
+    }
+
+    @Suppress("UNCHECKED_CAST")
+    private val knownCommands: MutableMap<String, Command>
+        get() = knownCommandsField.get(getCommandMap()) as MutableMap<String, Command>
+
+    override fun getCommandMap(): SimpleCommandMap {
+        return (Bukkit.getServer() as CraftServer).commandMap
+    }
+
+    override fun syncCommands() {
+        (Bukkit.getServer() as CraftServer).syncCommands()
+    }
+
+    override fun unregisterCommand(command: PluginCommandBase) {
+        knownCommands.remove(command.name)
+        knownCommands.remove("${command.plugin.name.lowercase()}:${command.name}")
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/CommonsInitializer.kt

@@ -0,0 +1,171 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3
+
+import com.willfp.eco.core.EcoPlugin
+import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
+import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
+import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
+import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.json.JSONComponentSerializer
+import net.minecraft.core.component.DataComponents
+import net.minecraft.core.registries.BuiltInRegistries
+import net.minecraft.nbt.CompoundTag
+import net.minecraft.nbt.Tag
+import net.minecraft.resources.ResourceLocation
+import net.minecraft.server.level.ServerPlayer
+import net.minecraft.world.entity.PathfinderMob
+import net.minecraft.world.item.Item
+import org.bukkit.Bukkit
+import org.bukkit.Material
+import org.bukkit.NamespacedKey
+import org.bukkit.craftbukkit.CraftServer
+import org.bukkit.craftbukkit.entity.CraftEntity
+import org.bukkit.craftbukkit.entity.CraftMob
+import org.bukkit.craftbukkit.entity.CraftPlayer
+import org.bukkit.craftbukkit.inventory.CraftItemStack
+import org.bukkit.craftbukkit.inventory.CraftMetaArmor
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataContainer
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataTypeRegistry
+import org.bukkit.craftbukkit.util.CraftMagicNumbers
+import org.bukkit.craftbukkit.util.CraftNamespacedKey
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Mob
+import org.bukkit.entity.Player
+import org.bukkit.inventory.ItemStack
+import org.bukkit.persistence.PersistentDataContainer
+import java.lang.reflect.Field
+
+class CommonsInitializer : CommonsInitializerProxy {
+    override fun init(plugin: EcoPlugin) {
+        CommonsProvider.setIfNeeded(CommonsProviderImpl)
+        plugin.onEnable {
+            plugin.eventManager.registerListener(PacketInjectorListener)
+        }
+    }
+
+    object CommonsProviderImpl : CommonsProvider {
+        private val cisHandle: Field = CraftItemStack::class.java.getDeclaredField("handle").apply {
+            isAccessible = true
+        }
+
+        private val pdcRegsitry = CraftMetaArmor::class.java
+            .superclass // Access CraftMetaItem
+            .getDeclaredField("DATA_TYPE_REGISTRY")
+            .apply { isAccessible = true }
+            .get(null) as CraftPersistentDataTypeRegistry
+
+        override val nbtTagString = CraftMagicNumbers.NBT.TAG_STRING
+
+        override fun toPathfinderMob(mob: Mob): PathfinderMob? {
+            val craft = mob as? CraftMob ?: return null
+            return craft.handle as? PathfinderMob
+        }
+
+        override fun toResourceLocation(namespacedKey: NamespacedKey): ResourceLocation =
+            CraftNamespacedKey.toMinecraft(namespacedKey)
+
+        override fun asNMSStack(itemStack: ItemStack): net.minecraft.world.item.ItemStack {
+            return if (itemStack !is CraftItemStack) {
+                CraftItemStack.asNMSCopy(itemStack)
+            } else {
+                cisHandle[itemStack] as net.minecraft.world.item.ItemStack? ?: CraftItemStack.asNMSCopy(itemStack)
+            }
+        }
+
+        override fun asBukkitStack(itemStack: net.minecraft.world.item.ItemStack): ItemStack {
+            return CraftItemStack.asCraftMirror(itemStack)
+        }
+
+        override fun mergeIfNeeded(itemStack: ItemStack, nmsStack: net.minecraft.world.item.ItemStack) {
+            if (itemStack !is CraftItemStack) {
+                itemStack.itemMeta = CraftItemStack.asCraftMirror(nmsStack).itemMeta
+            }
+        }
+
+        override fun toBukkitEntity(entity: net.minecraft.world.entity.LivingEntity): LivingEntity? =
+            CraftEntity.getEntity(Bukkit.getServer() as CraftServer, entity) as? LivingEntity
+
+        override fun makePdc(tag: CompoundTag, base: Boolean): PersistentDataContainer {
+            fun emptyPdc(): CraftPersistentDataContainer = CraftPersistentDataContainer(pdcRegsitry)
+
+            fun CompoundTag?.toPdc(): PersistentDataContainer {
+                val pdc = emptyPdc()
+                this ?: return pdc
+                val keys = this.allKeys
+                for (key in keys) {
+                    pdc.put(key, this[key])
+                }
+
+                return pdc
+            }
+
+            return if (base) {
+                tag.toPdc()
+            } else {
+                if (tag.contains("PublicBukkitValues")) {
+                    tag.getCompound("PublicBukkitValues").toPdc()
+                } else {
+                    emptyPdc()
+                }
+            }
+        }
+
+        override fun setPdc(
+            tag: CompoundTag,
+            pdc: PersistentDataContainer?,
+            item: net.minecraft.world.item.ItemStack?
+        ) {
+            fun CraftPersistentDataContainer.toTag(): CompoundTag {
+                val compound = CompoundTag()
+                val rawPublicMap: Map<String, Tag> = this.raw
+                for ((key, value) in rawPublicMap) {
+                    compound.put(key, value)
+                }
+
+                return compound
+            }
+
+            val container = when (pdc) {
+                is CraftPersistentDataContainer? -> pdc
+                else -> null
+            }
+
+            if (item != null) {
+                if (container != null && !container.isEmpty) {
+                    for (key in tag.allKeys.toSet()) {
+                        tag.remove(key)
+                    }
+
+                    tag.merge(container.toTag())
+                } else {
+                    item.remove(DataComponents.CUSTOM_DATA)
+                }
+            } else {
+                if (container != null && !container.isEmpty) {
+                    tag.put("PublicBukkitValues", container.toTag())
+                } else {
+                    tag.remove("PublicBukkitValues")
+                }
+            }
+        }
+
+        override fun materialToItem(material: Material): Item =
+            BuiltInRegistries.ITEM.getOptional(material.key.toResourceLocation())
+                .orElseThrow { IllegalArgumentException("Material is not item!") }
+
+        override fun itemToMaterial(item: Item) =
+            Material.getMaterial(BuiltInRegistries.ITEM.getKey(item).path.uppercase())
+                ?: throw IllegalArgumentException("Invalid material!")
+
+        override fun toNMS(player: Player): ServerPlayer {
+            return (player as CraftPlayer).handle
+        }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = JSONComponentSerializer.json().serialize(component)
+            val holderLookupProvider = (Bukkit.getServer() as CraftServer).server.registryAccess()
+
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json, holderLookupProvider)!!
+        }
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/DisplayName.kt

@@ -0,0 +1,57 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3
+
+import com.willfp.eco.core.packet.Packet
+import com.willfp.eco.core.packet.sendPacket
+import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import net.kyori.adventure.text.Component
+import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
+import net.minecraft.network.syncher.EntityDataAccessor
+import net.minecraft.network.syncher.SynchedEntityData
+import net.minecraft.world.entity.Entity
+import org.bukkit.craftbukkit.entity.CraftLivingEntity
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Player
+import java.util.Optional
+
+@Suppress("UNCHECKED_CAST")
+class DisplayName : DisplayNameProxy {
+    private val displayNameAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[2]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Optional<net.minecraft.network.chat.Component>>
+
+    private val customNameVisibleAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[3]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Boolean>
+
+    override fun setClientsideDisplayName(
+        entity: LivingEntity,
+        player: Player,
+        displayName: Component,
+        visible: Boolean
+    ) {
+        if (entity !is CraftLivingEntity) {
+            return
+        }
+
+        val nmsComponent = displayName.toNMS()
+
+        val nmsEntity = entity.handle
+
+        val packet = ClientboundSetEntityDataPacket(
+            nmsEntity.id,
+            listOf(
+                SynchedEntityData.DataValue.create(displayNameAccessor, Optional.of(nmsComponent)),
+                SynchedEntityData.DataValue.create(customNameVisibleAccessor, visible)
+            )
+        )
+
+        player.sendPacket(Packet(packet))
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/DummyEntityFactory.kt

@@ -0,0 +1,15 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3
+
+import com.willfp.eco.internal.entities.EcoDummyEntity
+import com.willfp.eco.internal.spigot.proxy.DummyEntityFactoryProxy
+import org.bukkit.Location
+import org.bukkit.craftbukkit.CraftWorld
+import org.bukkit.entity.Entity
+import org.bukkit.entity.Zombie
+
+class DummyEntityFactory : DummyEntityFactoryProxy {
+    override fun createDummyEntity(location: Location): Entity {
+        val world = location.world as CraftWorld
+        return EcoDummyEntity(world.createEntity(location, Zombie::class.java))
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/EntityControllerFactory.kt

@@ -0,0 +1,12 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3
+
+import com.willfp.eco.core.entities.ai.EntityController
+import com.willfp.eco.internal.spigot.proxy.EntityControllerFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.v1_21_3.entity.EcoEntityController
+import org.bukkit.entity.Mob
+
+class EntityControllerFactory : EntityControllerFactoryProxy {
+    override fun <T : Mob> createEntityController(entity: T): EntityController<T> {
+        return EcoEntityController(entity)
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/ExtendedPersistentDataContainerFactory.kt

@@ -0,0 +1,91 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3
+
+import com.willfp.eco.core.data.ExtendedPersistentDataContainer
+import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
+import net.minecraft.nbt.Tag
+import org.bukkit.Material
+import org.bukkit.craftbukkit.inventory.CraftItemStack
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataContainer
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataTypeRegistry
+import org.bukkit.inventory.ItemStack
+import org.bukkit.persistence.PersistentDataContainer
+import org.bukkit.persistence.PersistentDataType
+import java.lang.reflect.Field
+
+class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFactoryProxy {
+    private val registry: CraftPersistentDataTypeRegistry
+
+    init {
+        /*
+         Can't grab actual instance since it's in CraftMetaItem (which is package-private)
+         And getting it would mean more janky reflection
+         */
+        val item = CraftItemStack.asCraftCopy(ItemStack(Material.STONE))
+        val pdc = item.itemMeta!!.persistentDataContainer
+
+        // Cross-version compatibility:
+        val registryField: Field = try {
+            CraftPersistentDataContainer::class.java.getDeclaredField("registry")
+        } catch (e: NoSuchFieldException) {
+            CraftPersistentDataContainer::class.java.superclass.getDeclaredField("registry")
+        }
+
+        this.registry = registryField
+            .apply { isAccessible = true }.get(pdc) as CraftPersistentDataTypeRegistry
+    }
+
+    override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
+        return when (pdc) {
+            is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
+            else -> throw IllegalArgumentException("Custom PDC instance ${pdc::class.java.name} is not supported!")
+        }
+    }
+
+    override fun newPdc(): PersistentDataContainer {
+        return CraftPersistentDataContainer(registry)
+    }
+
+    inner class EcoPersistentDataContainer(
+        private val handle: CraftPersistentDataContainer
+    ) : ExtendedPersistentDataContainer {
+        @Suppress("UNCHECKED_CAST")
+        private val customDataTags: MutableMap<String, Tag> =
+            CraftPersistentDataContainer::class.java.getDeclaredField("customDataTags")
+                .apply { isAccessible = true }.get(handle) as MutableMap<String, Tag>
+
+        override fun <T : Any, Z : Any> set(key: String, dataType: PersistentDataType<T, Z>, value: Z) {
+            customDataTags[key] =
+                registry.wrap(dataType, dataType.toPrimitive(value, handle.adapterContext))
+        }
+
+        override fun <T : Any, Z : Any> has(key: String, dataType: PersistentDataType<T, Z>): Boolean {
+            val value = customDataTags[key] ?: return false
+            return registry.isInstanceOf(dataType, value)
+        }
+
+        override fun <T : Any, Z : Any> get(key: String, dataType: PersistentDataType<T, Z>): Z? {
+            val value = customDataTags[key] ?: return null
+            return dataType.fromPrimitive(registry.extract<T, Tag>(dataType, value), handle.adapterContext)
+        }
+
+        override fun <T : Any, Z : Any> getOrDefault(
+            key: String,
+            dataType: PersistentDataType<T, Z>,
+            defaultValue: Z
+        ): Z {
+            return get(key, dataType) ?: defaultValue
+        }
+
+        override fun remove(key: String) {
+            customDataTags.remove(key)
+        }
+
+        override fun getAllKeys(): MutableSet<String> {
+            return customDataTags.keys
+        }
+
+        override fun getBase(): PersistentDataContainer {
+            return handle
+        }
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/FastItemStackFactory.kt

@@ -0,0 +1,12 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3
+
+import com.willfp.eco.core.fast.FastItemStack
+import com.willfp.eco.internal.spigot.proxy.FastItemStackFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.common.modern.NewEcoFastItemStack
+import org.bukkit.inventory.ItemStack
+
+class FastItemStackFactory : FastItemStackFactoryProxy {
+    override fun create(itemStack: ItemStack): FastItemStack {
+        return NewEcoFastItemStack(itemStack)
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/MiniMessageTranslator.kt

@@ -0,0 +1,33 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3
+
+import com.willfp.eco.core.display.Display
+import com.willfp.eco.internal.spigot.proxy.MiniMessageTranslatorProxy
+import com.willfp.eco.util.toLegacy
+import net.kyori.adventure.text.minimessage.MiniMessage
+
+class MiniMessageTranslator : MiniMessageTranslatorProxy {
+    override fun format(message: String): String {
+        var mut = message
+
+        val startsWithPrefix = mut.startsWith(Display.PREFIX)
+        if (startsWithPrefix) {
+            mut = mut.substring(2)
+        }
+
+        mut = mut.replace('§', '&')
+
+        val miniMessage = runCatching {
+            MiniMessage.miniMessage().deserialize(
+                mut
+            ).toLegacy()
+        }.getOrNull() ?: mut
+
+        mut = if (startsWithPrefix) {
+            Display.PREFIX + miniMessage
+        } else {
+            miniMessage
+        }
+
+        return mut
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/PacketHandler.kt

@@ -0,0 +1,46 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3
+
+import com.willfp.eco.core.EcoPlugin
+import com.willfp.eco.core.packet.PacketListener
+import com.willfp.eco.internal.spigot.proxy.PacketHandlerProxy
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketHeldItemSlot
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketSetSlot
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketWindowItems
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.frame.clearFrames
+import com.willfp.eco.internal.spigot.proxy.v1_21_3.packet.NewItemsPacketOpenWindowMerchant
+import com.willfp.eco.internal.spigot.proxy.v1_21_3.packet.NewItemsPacketSetCreativeSlot
+import net.minecraft.network.protocol.Packet
+import org.bukkit.craftbukkit.entity.CraftPlayer
+import org.bukkit.entity.Player
+
+class PacketHandler : PacketHandlerProxy {
+    override fun sendPacket(player: Player, packet: com.willfp.eco.core.packet.Packet) {
+        if (player !is CraftPlayer) {
+            return
+        }
+
+        val handle = packet.handle
+
+        if (handle !is Packet<*>) {
+            return
+        }
+
+        player.handle.connection.send(handle)
+    }
+
+    override fun clearDisplayFrames() {
+        clearFrames()
+    }
+
+    override fun getPacketListeners(plugin: EcoPlugin): List<PacketListener> {
+        // No PacketAutoRecipe for 1.21.3+ because recipes have been changed internally
+
+        return listOf(
+            PacketHeldItemSlot,
+            NewItemsPacketOpenWindowMerchant,
+            NewItemsPacketSetCreativeSlot,
+            PacketSetSlot,
+            PacketWindowItems(plugin)
+        )
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/SNBTConverter.kt

@@ -0,0 +1,80 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3
+
+import com.mojang.serialization.Dynamic
+import com.willfp.eco.core.items.TestableItem
+import com.willfp.eco.core.recipe.parts.EmptyTestableItem
+import com.willfp.eco.internal.spigot.proxy.SNBTConverterProxy
+import net.minecraft.nbt.CompoundTag
+import net.minecraft.nbt.NbtOps
+import net.minecraft.nbt.SnbtPrinterTagVisitor
+import net.minecraft.nbt.TagParser
+import net.minecraft.server.MinecraftServer
+import net.minecraft.util.datafix.fixes.References
+import org.bukkit.Bukkit
+import org.bukkit.craftbukkit.CraftServer
+import org.bukkit.craftbukkit.inventory.CraftItemStack
+import org.bukkit.craftbukkit.util.CraftMagicNumbers
+import org.bukkit.inventory.ItemStack
+
+private val registryAccess = (Bukkit.getServer() as CraftServer).server.registryAccess()
+
+class SNBTConverter : SNBTConverterProxy {
+    private fun parseItemSNBT(snbt: String): CompoundTag? {
+        val nbt = runCatching { TagParser.parseTag(snbt) }.getOrNull() ?: return null
+        val dataVersion = if (nbt.contains("DataVersion")) {
+            nbt.getInt("DataVersion")
+        } else null
+
+        // If the data version is the same as the server's data version, we don't need to fix it
+        if (dataVersion == CraftMagicNumbers.INSTANCE.dataVersion) {
+            return nbt
+        }
+
+        return MinecraftServer.getServer().fixerUpper.update(
+            References.ITEM_STACK,
+            Dynamic(NbtOps.INSTANCE, nbt),
+            dataVersion ?: 3700, // 3700 is the 1.20.4 data version
+            CraftMagicNumbers.INSTANCE.dataVersion
+        ).value as CompoundTag
+    }
+
+    override fun fromSNBT(snbt: String): ItemStack? {
+        val tag = parseItemSNBT(snbt) ?: return null
+        val nms = net.minecraft.world.item.ItemStack.parse(registryAccess, tag).orElse(null) ?: return null
+        return CraftItemStack.asBukkitCopy(nms)
+    }
+
+    override fun toSNBT(itemStack: ItemStack): String {
+        val nms = CraftItemStack.asNMSCopy(itemStack)
+        val tag = nms.save(registryAccess) as CompoundTag
+        tag.putInt("DataVersion", CraftMagicNumbers.INSTANCE.dataVersion)
+        return SnbtPrinterTagVisitor().visit(tag)
+    }
+
+    override fun makeSNBTTestable(snbt: String): TestableItem {
+        val tag = parseItemSNBT(snbt) ?: return EmptyTestableItem()
+        val nms = net.minecraft.world.item.ItemStack.parse(registryAccess, tag).orElse(null)
+            ?: return EmptyTestableItem()
+
+        tag.remove("Count")
+        return SNBTTestableItem(CraftItemStack.asBukkitCopy(nms), tag)
+    }
+
+    class SNBTTestableItem(
+        private val item: ItemStack,
+        private val tag: CompoundTag
+    ) : TestableItem {
+        override fun matches(itemStack: ItemStack?): Boolean {
+            if (itemStack == null) {
+                return false
+            }
+
+            val nms = CraftItemStack.asNMSCopy(itemStack)
+            val nmsTag = nms.save(registryAccess) as CompoundTag
+            nmsTag.remove("Count")
+            return tag.copy().merge(nmsTag) == nmsTag && itemStack.type == item.type
+        }
+
+        override fun getItem(): ItemStack = item
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/Skull.kt

@@ -0,0 +1,18 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3
+
+import com.willfp.eco.internal.spigot.proxy.SkullProxy
+import com.willfp.eco.internal.spigot.proxy.common.modern.texture
+import org.bukkit.inventory.meta.SkullMeta
+
+class Skull : SkullProxy {
+    override fun setSkullTexture(
+        meta: SkullMeta,
+        base64: String
+    ) {
+        meta.texture = base64
+    }
+
+    override fun getSkullTexture(
+        meta: SkullMeta
+    ): String? = meta.texture
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/TPS.kt

@@ -0,0 +1,11 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3
+
+import com.willfp.eco.internal.spigot.proxy.TPSProxy
+import org.bukkit.Bukkit
+import org.bukkit.craftbukkit.CraftServer
+
+class TPS : TPSProxy {
+    override fun getTPS(): Double {
+        return (Bukkit.getServer() as CraftServer).handle.server.tps1.average
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/entity/EcoEntityController.kt

@@ -0,0 +1,95 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3.entity
+
+import com.willfp.eco.core.entities.ai.CustomGoal
+import com.willfp.eco.core.entities.ai.EntityController
+import com.willfp.eco.core.entities.ai.EntityGoal
+import com.willfp.eco.core.entities.ai.TargetGoal
+import com.willfp.eco.internal.spigot.proxy.common.ai.CustomGoalFactory
+import com.willfp.eco.internal.spigot.proxy.common.ai.getGoalFactory
+import com.willfp.eco.internal.spigot.proxy.common.toPathfinderMob
+import net.minecraft.world.entity.PathfinderMob
+import net.minecraft.world.entity.ai.goal.Goal
+import org.bukkit.entity.Mob
+
+class EcoEntityController<T : Mob>(
+    private val handle: T
+) : EntityController<T> {
+    override fun addEntityGoal(priority: Int, goal: EntityGoal<in T>): EntityController<T> {
+        val nms = getNms() ?: return this
+
+        nms.goalSelector.addGoal(
+            priority,
+            goal.getGoalFactory()?.create(goal, nms) ?: return this
+        )
+
+        return this
+    }
+
+    override fun removeEntityGoal(goal: EntityGoal<in T>): EntityController<T> {
+        val nms = getNms() ?: return this
+
+        val predicate: (Goal) -> Boolean = if (goal is CustomGoal<*>) {
+            { CustomGoalFactory.isGoalOfType(it, goal) }
+        } else {
+            { goal.getGoalFactory()?.isGoalOfType(it) == true }
+        }
+
+        for (wrapped in nms.goalSelector.availableGoals.toSet()) {
+            if (predicate(wrapped.goal)) {
+                nms.goalSelector.removeGoal(wrapped.goal)
+            }
+        }
+
+        return this
+    }
+
+    override fun clearEntityGoals(): EntityController<T> {
+        val nms = getNms() ?: return this
+        nms.goalSelector.availableGoals.clear()
+        return this
+    }
+
+    override fun addTargetGoal(priority: Int, goal: TargetGoal<in T>): EntityController<T> {
+        val nms = getNms() ?: return this
+
+        nms.targetSelector.addGoal(
+            priority, goal.getGoalFactory()?.create(goal, nms) ?: return this
+        )
+
+        nms.targetSelector
+
+        return this
+    }
+
+    override fun removeTargetGoal(goal: TargetGoal<in T>): EntityController<T> {
+        val nms = getNms() ?: return this
+
+        val predicate: (Goal) -> Boolean = if (goal is CustomGoal<*>) {
+            { CustomGoalFactory.isGoalOfType(it, goal) }
+        } else {
+            { goal.getGoalFactory()?.isGoalOfType(it) == true }
+        }
+
+        for (wrapped in nms.targetSelector.availableGoals.toSet()) {
+            if (predicate(wrapped.goal)) {
+                nms.targetSelector.removeGoal(wrapped.goal)
+            }
+        }
+
+        return this
+    }
+
+    override fun clearTargetGoals(): EntityController<T> {
+        val nms = getNms() ?: return this
+        nms.targetSelector.availableGoals.clear()
+        return this
+    }
+
+    private fun getNms(): PathfinderMob? {
+        return handle.toPathfinderMob()
+    }
+
+    override fun getEntity(): T {
+        return handle
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/packet/NewItemsPacketOpenWindowMerchant.kt

@@ -0,0 +1,35 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3.packet
+
+import com.willfp.eco.core.display.Display
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.core.packet.PacketListener
+import com.willfp.eco.internal.spigot.proxy.common.asBukkitStack
+import net.minecraft.network.protocol.game.ClientboundMerchantOffersPacket
+import net.minecraft.world.item.trading.MerchantOffers
+
+object NewItemsPacketOpenWindowMerchant : PacketListener {
+    private val field = ClientboundMerchantOffersPacket::class.java
+        .declaredFields
+        .first { it.type == MerchantOffers::class.java }
+        .apply { isAccessible = true }
+
+    override fun onSend(event: PacketEvent) {
+        val packet = event.packet.handle as? ClientboundMerchantOffersPacket ?: return
+
+        val offers = MerchantOffers()
+
+        for (offer in packet.offers) {
+            val new = offer.copy()
+
+            Display.display(new.baseCostA.itemStack.asBukkitStack(), event.player)
+            if (new.costB.isPresent) {
+                Display.display(new.costB.get().itemStack.asBukkitStack(), event.player)
+            }
+            Display.display(new.result.asBukkitStack(), event.player)
+
+            offers += new
+        }
+
+        field.set(packet, offers)
+    }
+}

eco-core/core-nms/v1_21_3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_3/packet/NewItemsPacketSetCreativeSlot.kt

@@ -0,0 +1,19 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_3.packet
+
+import com.willfp.eco.core.display.Display
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.core.packet.PacketListener
+import com.willfp.eco.internal.spigot.proxy.common.asBukkitStack
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.frame.DisplayFrame
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.frame.lastDisplayFrame
+import net.minecraft.network.protocol.game.ServerboundSetCreativeModeSlotPacket
+
+object NewItemsPacketSetCreativeSlot : PacketListener {
+    override fun onReceive(event: PacketEvent) {
+        val packet = event.packet.handle as? ServerboundSetCreativeModeSlotPacket ?: return
+
+        Display.revert(packet.itemStack.asBukkitStack())
+
+        event.player.lastDisplayFrame = DisplayFrame.EMPTY
+    }
+}

eco-core/core-nms/v1_21_4/build.gradle.kts

@@ -0,0 +1,52 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+plugins {
+    id("io.papermc.paperweight.userdev")
+}
+
+group = "com.willfp"
+version = rootProject.version
+
+dependencies {
+    implementation(project(":eco-core:core-nms:modern"))
+    implementation(project(":eco-core:core-nms:common"))
+    paperweight.paperDevBundle("1.21.4-R0.1-SNAPSHOT")
+
+    implementation("net.kyori:adventure-text-minimessage:4.11.0") {
+        version {
+            strictly("4.11.0")
+        }
+        exclude(group = "net.kyori", module = "adventure-api")
+    }
+}
+
+tasks {
+    build {
+        dependsOn(reobfJar)
+    }
+
+    reobfJar {
+        mustRunAfter(shadowJar)
+    }
+
+    shadowJar {
+        relocate(
+            "com.willfp.eco.internal.spigot.proxy.common",
+            "com.willfp.eco.internal.spigot.proxy.v1_21_4.common"
+        )
+        relocate(
+            "net.kyori.adventure.text.minimessage",
+            "com.willfp.eco.internal.spigot.proxy.v1_21_4.minimessage"
+        )
+    }
+
+    compileJava {
+        options.release.set(21)
+    }
+
+    compileKotlin {
+        compilerOptions {
+            jvmTarget.set(JvmTarget.JVM_21)
+        }
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/BukkitCommands.kt

@@ -0,0 +1,35 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4
+
+import com.willfp.eco.core.command.PluginCommandBase
+import com.willfp.eco.internal.spigot.proxy.BukkitCommandsProxy
+import org.bukkit.Bukkit
+import org.bukkit.command.Command
+import org.bukkit.command.SimpleCommandMap
+import org.bukkit.craftbukkit.CraftServer
+import java.lang.reflect.Field
+
+class BukkitCommands : BukkitCommandsProxy {
+    private val knownCommandsField: Field by lazy {
+        SimpleCommandMap::class.java.getDeclaredField("knownCommands")
+            .apply {
+                isAccessible = true
+            }
+    }
+
+    @Suppress("UNCHECKED_CAST")
+    private val knownCommands: MutableMap<String, Command>
+        get() = knownCommandsField.get(getCommandMap()) as MutableMap<String, Command>
+
+    override fun getCommandMap(): SimpleCommandMap {
+        return (Bukkit.getServer() as CraftServer).commandMap
+    }
+
+    override fun syncCommands() {
+        (Bukkit.getServer() as CraftServer).syncCommands()
+    }
+
+    override fun unregisterCommand(command: PluginCommandBase) {
+        knownCommands.remove(command.name)
+        knownCommands.remove("${command.plugin.name.lowercase()}:${command.name}")
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/CommonsInitializer.kt

@@ -0,0 +1,171 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4
+
+import com.willfp.eco.core.EcoPlugin
+import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
+import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
+import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
+import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.json.JSONComponentSerializer
+import net.minecraft.core.component.DataComponents
+import net.minecraft.core.registries.BuiltInRegistries
+import net.minecraft.nbt.CompoundTag
+import net.minecraft.nbt.Tag
+import net.minecraft.resources.ResourceLocation
+import net.minecraft.server.level.ServerPlayer
+import net.minecraft.world.entity.PathfinderMob
+import net.minecraft.world.item.Item
+import org.bukkit.Bukkit
+import org.bukkit.Material
+import org.bukkit.NamespacedKey
+import org.bukkit.craftbukkit.CraftServer
+import org.bukkit.craftbukkit.entity.CraftEntity
+import org.bukkit.craftbukkit.entity.CraftMob
+import org.bukkit.craftbukkit.entity.CraftPlayer
+import org.bukkit.craftbukkit.inventory.CraftItemStack
+import org.bukkit.craftbukkit.inventory.CraftMetaArmor
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataContainer
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataTypeRegistry
+import org.bukkit.craftbukkit.util.CraftMagicNumbers
+import org.bukkit.craftbukkit.util.CraftNamespacedKey
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Mob
+import org.bukkit.entity.Player
+import org.bukkit.inventory.ItemStack
+import org.bukkit.persistence.PersistentDataContainer
+import java.lang.reflect.Field
+
+class CommonsInitializer : CommonsInitializerProxy {
+    override fun init(plugin: EcoPlugin) {
+        CommonsProvider.setIfNeeded(CommonsProviderImpl)
+        plugin.onEnable {
+            plugin.eventManager.registerListener(PacketInjectorListener)
+        }
+    }
+
+    object CommonsProviderImpl : CommonsProvider {
+        private val cisHandle: Field = CraftItemStack::class.java.getDeclaredField("handle").apply {
+            isAccessible = true
+        }
+
+        private val pdcRegsitry = CraftMetaArmor::class.java
+            .superclass // Access CraftMetaItem
+            .getDeclaredField("DATA_TYPE_REGISTRY")
+            .apply { isAccessible = true }
+            .get(null) as CraftPersistentDataTypeRegistry
+
+        override val nbtTagString = CraftMagicNumbers.NBT.TAG_STRING
+
+        override fun toPathfinderMob(mob: Mob): PathfinderMob? {
+            val craft = mob as? CraftMob ?: return null
+            return craft.handle as? PathfinderMob
+        }
+
+        override fun toResourceLocation(namespacedKey: NamespacedKey): ResourceLocation =
+            CraftNamespacedKey.toMinecraft(namespacedKey)
+
+        override fun asNMSStack(itemStack: ItemStack): net.minecraft.world.item.ItemStack {
+            return if (itemStack !is CraftItemStack) {
+                CraftItemStack.asNMSCopy(itemStack)
+            } else {
+                cisHandle[itemStack] as net.minecraft.world.item.ItemStack? ?: CraftItemStack.asNMSCopy(itemStack)
+            }
+        }
+
+        override fun asBukkitStack(itemStack: net.minecraft.world.item.ItemStack): ItemStack {
+            return CraftItemStack.asCraftMirror(itemStack)
+        }
+
+        override fun mergeIfNeeded(itemStack: ItemStack, nmsStack: net.minecraft.world.item.ItemStack) {
+            if (itemStack !is CraftItemStack) {
+                itemStack.itemMeta = CraftItemStack.asCraftMirror(nmsStack).itemMeta
+            }
+        }
+
+        override fun toBukkitEntity(entity: net.minecraft.world.entity.LivingEntity): LivingEntity? =
+            CraftEntity.getEntity(Bukkit.getServer() as CraftServer, entity) as? LivingEntity
+
+        override fun makePdc(tag: CompoundTag, base: Boolean): PersistentDataContainer {
+            fun emptyPdc(): CraftPersistentDataContainer = CraftPersistentDataContainer(pdcRegsitry)
+
+            fun CompoundTag?.toPdc(): PersistentDataContainer {
+                val pdc = emptyPdc()
+                this ?: return pdc
+                val keys = this.allKeys
+                for (key in keys) {
+                    pdc.put(key, this[key])
+                }
+
+                return pdc
+            }
+
+            return if (base) {
+                tag.toPdc()
+            } else {
+                if (tag.contains("PublicBukkitValues")) {
+                    tag.getCompound("PublicBukkitValues").toPdc()
+                } else {
+                    emptyPdc()
+                }
+            }
+        }
+
+        override fun setPdc(
+            tag: CompoundTag,
+            pdc: PersistentDataContainer?,
+            item: net.minecraft.world.item.ItemStack?
+        ) {
+            fun CraftPersistentDataContainer.toTag(): CompoundTag {
+                val compound = CompoundTag()
+                val rawPublicMap: Map<String, Tag> = this.raw
+                for ((key, value) in rawPublicMap) {
+                    compound.put(key, value)
+                }
+
+                return compound
+            }
+
+            val container = when (pdc) {
+                is CraftPersistentDataContainer? -> pdc
+                else -> null
+            }
+
+            if (item != null) {
+                if (container != null && !container.isEmpty) {
+                    for (key in tag.allKeys.toSet()) {
+                        tag.remove(key)
+                    }
+
+                    tag.merge(container.toTag())
+                } else {
+                    item.remove(DataComponents.CUSTOM_DATA)
+                }
+            } else {
+                if (container != null && !container.isEmpty) {
+                    tag.put("PublicBukkitValues", container.toTag())
+                } else {
+                    tag.remove("PublicBukkitValues")
+                }
+            }
+        }
+
+        override fun materialToItem(material: Material): Item =
+            BuiltInRegistries.ITEM.getOptional(material.key.toResourceLocation())
+                .orElseThrow { IllegalArgumentException("Material is not item!") }
+
+        override fun itemToMaterial(item: Item) =
+            Material.getMaterial(BuiltInRegistries.ITEM.getKey(item).path.uppercase())
+                ?: throw IllegalArgumentException("Invalid material!")
+
+        override fun toNMS(player: Player): ServerPlayer {
+            return (player as CraftPlayer).handle
+        }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = JSONComponentSerializer.json().serialize(component)
+            val holderLookupProvider = (Bukkit.getServer() as CraftServer).server.registryAccess()
+
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json, holderLookupProvider)!!
+        }
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/DisplayName.kt

@@ -0,0 +1,57 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4
+
+import com.willfp.eco.core.packet.Packet
+import com.willfp.eco.core.packet.sendPacket
+import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import net.kyori.adventure.text.Component
+import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
+import net.minecraft.network.syncher.EntityDataAccessor
+import net.minecraft.network.syncher.SynchedEntityData
+import net.minecraft.world.entity.Entity
+import org.bukkit.craftbukkit.entity.CraftLivingEntity
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Player
+import java.util.Optional
+
+@Suppress("UNCHECKED_CAST")
+class DisplayName : DisplayNameProxy {
+    private val displayNameAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[2]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Optional<net.minecraft.network.chat.Component>>
+
+    private val customNameVisibleAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[3]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Boolean>
+
+    override fun setClientsideDisplayName(
+        entity: LivingEntity,
+        player: Player,
+        displayName: Component,
+        visible: Boolean
+    ) {
+        if (entity !is CraftLivingEntity) {
+            return
+        }
+
+        val nmsComponent = displayName.toNMS()
+
+        val nmsEntity = entity.handle
+
+        val packet = ClientboundSetEntityDataPacket(
+            nmsEntity.id,
+            listOf(
+                SynchedEntityData.DataValue.create(displayNameAccessor, Optional.of(nmsComponent)),
+                SynchedEntityData.DataValue.create(customNameVisibleAccessor, visible)
+            )
+        )
+
+        player.sendPacket(Packet(packet))
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/DummyEntityFactory.kt

@@ -0,0 +1,15 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4
+
+import com.willfp.eco.internal.entities.EcoDummyEntity
+import com.willfp.eco.internal.spigot.proxy.DummyEntityFactoryProxy
+import org.bukkit.Location
+import org.bukkit.craftbukkit.CraftWorld
+import org.bukkit.entity.Entity
+import org.bukkit.entity.Zombie
+
+class DummyEntityFactory : DummyEntityFactoryProxy {
+    override fun createDummyEntity(location: Location): Entity {
+        val world = location.world as CraftWorld
+        return EcoDummyEntity(world.createEntity(location, Zombie::class.java))
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/EntityControllerFactory.kt

@@ -0,0 +1,12 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4
+
+import com.willfp.eco.core.entities.ai.EntityController
+import com.willfp.eco.internal.spigot.proxy.EntityControllerFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.v1_21_4.entity.EcoEntityController
+import org.bukkit.entity.Mob
+
+class EntityControllerFactory : EntityControllerFactoryProxy {
+    override fun <T : Mob> createEntityController(entity: T): EntityController<T> {
+        return EcoEntityController(entity)
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/ExtendedPersistentDataContainerFactory.kt

@@ -0,0 +1,91 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4
+
+import com.willfp.eco.core.data.ExtendedPersistentDataContainer
+import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
+import net.minecraft.nbt.Tag
+import org.bukkit.Material
+import org.bukkit.craftbukkit.inventory.CraftItemStack
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataContainer
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataTypeRegistry
+import org.bukkit.inventory.ItemStack
+import org.bukkit.persistence.PersistentDataContainer
+import org.bukkit.persistence.PersistentDataType
+import java.lang.reflect.Field
+
+class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFactoryProxy {
+    private val registry: CraftPersistentDataTypeRegistry
+
+    init {
+        /*
+         Can't grab actual instance since it's in CraftMetaItem (which is package-private)
+         And getting it would mean more janky reflection
+         */
+        val item = CraftItemStack.asCraftCopy(ItemStack(Material.STONE))
+        val pdc = item.itemMeta!!.persistentDataContainer
+
+        // Cross-version compatibility:
+        val registryField: Field = try {
+            CraftPersistentDataContainer::class.java.getDeclaredField("registry")
+        } catch (e: NoSuchFieldException) {
+            CraftPersistentDataContainer::class.java.superclass.getDeclaredField("registry")
+        }
+
+        this.registry = registryField
+            .apply { isAccessible = true }.get(pdc) as CraftPersistentDataTypeRegistry
+    }
+
+    override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
+        return when (pdc) {
+            is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
+            else -> throw IllegalArgumentException("Custom PDC instance ${pdc::class.java.name} is not supported!")
+        }
+    }
+
+    override fun newPdc(): PersistentDataContainer {
+        return CraftPersistentDataContainer(registry)
+    }
+
+    inner class EcoPersistentDataContainer(
+        private val handle: CraftPersistentDataContainer
+    ) : ExtendedPersistentDataContainer {
+        @Suppress("UNCHECKED_CAST")
+        private val customDataTags: MutableMap<String, Tag> =
+            CraftPersistentDataContainer::class.java.getDeclaredField("customDataTags")
+                .apply { isAccessible = true }.get(handle) as MutableMap<String, Tag>
+
+        override fun <T : Any, Z : Any> set(key: String, dataType: PersistentDataType<T, Z>, value: Z) {
+            customDataTags[key] =
+                registry.wrap(dataType, dataType.toPrimitive(value, handle.adapterContext))
+        }
+
+        override fun <T : Any, Z : Any> has(key: String, dataType: PersistentDataType<T, Z>): Boolean {
+            val value = customDataTags[key] ?: return false
+            return registry.isInstanceOf(dataType, value)
+        }
+
+        override fun <T : Any, Z : Any> get(key: String, dataType: PersistentDataType<T, Z>): Z? {
+            val value = customDataTags[key] ?: return null
+            return dataType.fromPrimitive(registry.extract<T, Tag>(dataType, value), handle.adapterContext)
+        }
+
+        override fun <T : Any, Z : Any> getOrDefault(
+            key: String,
+            dataType: PersistentDataType<T, Z>,
+            defaultValue: Z
+        ): Z {
+            return get(key, dataType) ?: defaultValue
+        }
+
+        override fun remove(key: String) {
+            customDataTags.remove(key)
+        }
+
+        override fun getAllKeys(): MutableSet<String> {
+            return customDataTags.keys
+        }
+
+        override fun getBase(): PersistentDataContainer {
+            return handle
+        }
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/FastItemStackFactory.kt

@@ -0,0 +1,12 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4
+
+import com.willfp.eco.core.fast.FastItemStack
+import com.willfp.eco.internal.spigot.proxy.FastItemStackFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.common.modern.NewEcoFastItemStack
+import org.bukkit.inventory.ItemStack
+
+class FastItemStackFactory : FastItemStackFactoryProxy {
+    override fun create(itemStack: ItemStack): FastItemStack {
+        return NewEcoFastItemStack(itemStack)
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/MiniMessageTranslator.kt

@@ -0,0 +1,33 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4
+
+import com.willfp.eco.core.display.Display
+import com.willfp.eco.internal.spigot.proxy.MiniMessageTranslatorProxy
+import com.willfp.eco.util.toLegacy
+import net.kyori.adventure.text.minimessage.MiniMessage
+
+class MiniMessageTranslator : MiniMessageTranslatorProxy {
+    override fun format(message: String): String {
+        var mut = message
+
+        val startsWithPrefix = mut.startsWith(Display.PREFIX)
+        if (startsWithPrefix) {
+            mut = mut.substring(2)
+        }
+
+        mut = mut.replace('§', '&')
+
+        val miniMessage = runCatching {
+            MiniMessage.miniMessage().deserialize(
+                mut
+            ).toLegacy()
+        }.getOrNull() ?: mut
+
+        mut = if (startsWithPrefix) {
+            Display.PREFIX + miniMessage
+        } else {
+            miniMessage
+        }
+
+        return mut
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/PacketHandler.kt

@@ -0,0 +1,46 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4
+
+import com.willfp.eco.core.EcoPlugin
+import com.willfp.eco.core.packet.PacketListener
+import com.willfp.eco.internal.spigot.proxy.PacketHandlerProxy
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketHeldItemSlot
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketSetSlot
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketWindowItems
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.frame.clearFrames
+import com.willfp.eco.internal.spigot.proxy.v1_21_4.packet.NewItemsPacketOpenWindowMerchant
+import com.willfp.eco.internal.spigot.proxy.v1_21_4.packet.NewItemsPacketSetCreativeSlot
+import net.minecraft.network.protocol.Packet
+import org.bukkit.craftbukkit.entity.CraftPlayer
+import org.bukkit.entity.Player
+
+class PacketHandler : PacketHandlerProxy {
+    override fun sendPacket(player: Player, packet: com.willfp.eco.core.packet.Packet) {
+        if (player !is CraftPlayer) {
+            return
+        }
+
+        val handle = packet.handle
+
+        if (handle !is Packet<*>) {
+            return
+        }
+
+        player.handle.connection.send(handle)
+    }
+
+    override fun clearDisplayFrames() {
+        clearFrames()
+    }
+
+    override fun getPacketListeners(plugin: EcoPlugin): List<PacketListener> {
+        // No PacketAutoRecipe for 1.21.3+ because recipes have been changed internally
+
+        return listOf(
+            PacketHeldItemSlot,
+            NewItemsPacketOpenWindowMerchant,
+            NewItemsPacketSetCreativeSlot,
+            PacketSetSlot,
+            PacketWindowItems(plugin)
+        )
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/SNBTConverter.kt

@@ -0,0 +1,80 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4
+
+import com.mojang.serialization.Dynamic
+import com.willfp.eco.core.items.TestableItem
+import com.willfp.eco.core.recipe.parts.EmptyTestableItem
+import com.willfp.eco.internal.spigot.proxy.SNBTConverterProxy
+import net.minecraft.nbt.CompoundTag
+import net.minecraft.nbt.NbtOps
+import net.minecraft.nbt.SnbtPrinterTagVisitor
+import net.minecraft.nbt.TagParser
+import net.minecraft.server.MinecraftServer
+import net.minecraft.util.datafix.fixes.References
+import org.bukkit.Bukkit
+import org.bukkit.craftbukkit.CraftServer
+import org.bukkit.craftbukkit.inventory.CraftItemStack
+import org.bukkit.craftbukkit.util.CraftMagicNumbers
+import org.bukkit.inventory.ItemStack
+
+private val registryAccess = (Bukkit.getServer() as CraftServer).server.registryAccess()
+
+class SNBTConverter : SNBTConverterProxy {
+    private fun parseItemSNBT(snbt: String): CompoundTag? {
+        val nbt = runCatching { TagParser.parseTag(snbt) }.getOrNull() ?: return null
+        val dataVersion = if (nbt.contains("DataVersion")) {
+            nbt.getInt("DataVersion")
+        } else null
+
+        // If the data version is the same as the server's data version, we don't need to fix it
+        if (dataVersion == CraftMagicNumbers.INSTANCE.dataVersion) {
+            return nbt
+        }
+
+        return MinecraftServer.getServer().fixerUpper.update(
+            References.ITEM_STACK,
+            Dynamic(NbtOps.INSTANCE, nbt),
+            dataVersion ?: 3700, // 3700 is the 1.20.4 data version
+            CraftMagicNumbers.INSTANCE.dataVersion
+        ).value as CompoundTag
+    }
+
+    override fun fromSNBT(snbt: String): ItemStack? {
+        val tag = parseItemSNBT(snbt) ?: return null
+        val nms = net.minecraft.world.item.ItemStack.parse(registryAccess, tag).orElse(null) ?: return null
+        return CraftItemStack.asBukkitCopy(nms)
+    }
+
+    override fun toSNBT(itemStack: ItemStack): String {
+        val nms = CraftItemStack.asNMSCopy(itemStack)
+        val tag = nms.save(registryAccess) as CompoundTag
+        tag.putInt("DataVersion", CraftMagicNumbers.INSTANCE.dataVersion)
+        return SnbtPrinterTagVisitor().visit(tag)
+    }
+
+    override fun makeSNBTTestable(snbt: String): TestableItem {
+        val tag = parseItemSNBT(snbt) ?: return EmptyTestableItem()
+        val nms = net.minecraft.world.item.ItemStack.parse(registryAccess, tag).orElse(null)
+            ?: return EmptyTestableItem()
+
+        tag.remove("Count")
+        return SNBTTestableItem(CraftItemStack.asBukkitCopy(nms), tag)
+    }
+
+    class SNBTTestableItem(
+        private val item: ItemStack,
+        private val tag: CompoundTag
+    ) : TestableItem {
+        override fun matches(itemStack: ItemStack?): Boolean {
+            if (itemStack == null) {
+                return false
+            }
+
+            val nms = CraftItemStack.asNMSCopy(itemStack)
+            val nmsTag = nms.save(registryAccess) as CompoundTag
+            nmsTag.remove("Count")
+            return tag.copy().merge(nmsTag) == nmsTag && itemStack.type == item.type
+        }
+
+        override fun getItem(): ItemStack = item
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/Skull.kt

@@ -0,0 +1,18 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4
+
+import com.willfp.eco.internal.spigot.proxy.SkullProxy
+import com.willfp.eco.internal.spigot.proxy.common.modern.texture
+import org.bukkit.inventory.meta.SkullMeta
+
+class Skull : SkullProxy {
+    override fun setSkullTexture(
+        meta: SkullMeta,
+        base64: String
+    ) {
+        meta.texture = base64
+    }
+
+    override fun getSkullTexture(
+        meta: SkullMeta
+    ): String? = meta.texture
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/TPS.kt

@@ -0,0 +1,11 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4
+
+import com.willfp.eco.internal.spigot.proxy.TPSProxy
+import org.bukkit.Bukkit
+import org.bukkit.craftbukkit.CraftServer
+
+class TPS : TPSProxy {
+    override fun getTPS(): Double {
+        return (Bukkit.getServer() as CraftServer).handle.server.tps1.average
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/entity/EcoEntityController.kt

@@ -0,0 +1,95 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4.entity
+
+import com.willfp.eco.core.entities.ai.CustomGoal
+import com.willfp.eco.core.entities.ai.EntityController
+import com.willfp.eco.core.entities.ai.EntityGoal
+import com.willfp.eco.core.entities.ai.TargetGoal
+import com.willfp.eco.internal.spigot.proxy.common.ai.CustomGoalFactory
+import com.willfp.eco.internal.spigot.proxy.common.ai.getGoalFactory
+import com.willfp.eco.internal.spigot.proxy.common.toPathfinderMob
+import net.minecraft.world.entity.PathfinderMob
+import net.minecraft.world.entity.ai.goal.Goal
+import org.bukkit.entity.Mob
+
+class EcoEntityController<T : Mob>(
+    private val handle: T
+) : EntityController<T> {
+    override fun addEntityGoal(priority: Int, goal: EntityGoal<in T>): EntityController<T> {
+        val nms = getNms() ?: return this
+
+        nms.goalSelector.addGoal(
+            priority,
+            goal.getGoalFactory()?.create(goal, nms) ?: return this
+        )
+
+        return this
+    }
+
+    override fun removeEntityGoal(goal: EntityGoal<in T>): EntityController<T> {
+        val nms = getNms() ?: return this
+
+        val predicate: (Goal) -> Boolean = if (goal is CustomGoal<*>) {
+            { CustomGoalFactory.isGoalOfType(it, goal) }
+        } else {
+            { goal.getGoalFactory()?.isGoalOfType(it) == true }
+        }
+
+        for (wrapped in nms.goalSelector.availableGoals.toSet()) {
+            if (predicate(wrapped.goal)) {
+                nms.goalSelector.removeGoal(wrapped.goal)
+            }
+        }
+
+        return this
+    }
+
+    override fun clearEntityGoals(): EntityController<T> {
+        val nms = getNms() ?: return this
+        nms.goalSelector.availableGoals.clear()
+        return this
+    }
+
+    override fun addTargetGoal(priority: Int, goal: TargetGoal<in T>): EntityController<T> {
+        val nms = getNms() ?: return this
+
+        nms.targetSelector.addGoal(
+            priority, goal.getGoalFactory()?.create(goal, nms) ?: return this
+        )
+
+        nms.targetSelector
+
+        return this
+    }
+
+    override fun removeTargetGoal(goal: TargetGoal<in T>): EntityController<T> {
+        val nms = getNms() ?: return this
+
+        val predicate: (Goal) -> Boolean = if (goal is CustomGoal<*>) {
+            { CustomGoalFactory.isGoalOfType(it, goal) }
+        } else {
+            { goal.getGoalFactory()?.isGoalOfType(it) == true }
+        }
+
+        for (wrapped in nms.targetSelector.availableGoals.toSet()) {
+            if (predicate(wrapped.goal)) {
+                nms.targetSelector.removeGoal(wrapped.goal)
+            }
+        }
+
+        return this
+    }
+
+    override fun clearTargetGoals(): EntityController<T> {
+        val nms = getNms() ?: return this
+        nms.targetSelector.availableGoals.clear()
+        return this
+    }
+
+    private fun getNms(): PathfinderMob? {
+        return handle.toPathfinderMob()
+    }
+
+    override fun getEntity(): T {
+        return handle
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/packet/NewItemsPacketOpenWindowMerchant.kt

@@ -0,0 +1,35 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4.packet
+
+import com.willfp.eco.core.display.Display
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.core.packet.PacketListener
+import com.willfp.eco.internal.spigot.proxy.common.asBukkitStack
+import net.minecraft.network.protocol.game.ClientboundMerchantOffersPacket
+import net.minecraft.world.item.trading.MerchantOffers
+
+object NewItemsPacketOpenWindowMerchant : PacketListener {
+    private val field = ClientboundMerchantOffersPacket::class.java
+        .declaredFields
+        .first { it.type == MerchantOffers::class.java }
+        .apply { isAccessible = true }
+
+    override fun onSend(event: PacketEvent) {
+        val packet = event.packet.handle as? ClientboundMerchantOffersPacket ?: return
+
+        val offers = MerchantOffers()
+
+        for (offer in packet.offers) {
+            val new = offer.copy()
+
+            Display.display(new.baseCostA.itemStack.asBukkitStack(), event.player)
+            if (new.costB.isPresent) {
+                Display.display(new.costB.get().itemStack.asBukkitStack(), event.player)
+            }
+            Display.display(new.result.asBukkitStack(), event.player)
+
+            offers += new
+        }
+
+        field.set(packet, offers)
+    }
+}

eco-core/core-nms/v1_21_4/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_4/packet/NewItemsPacketSetCreativeSlot.kt

@@ -0,0 +1,20 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_4.packet
+
+import com.willfp.eco.core.display.Display
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.core.packet.PacketListener
+import com.willfp.eco.internal.spigot.proxy.common.asBukkitStack
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.frame.DisplayFrame
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.frame.lastDisplayFrame
+import net.minecraft.network.protocol.game.ClientboundContainerSetContentPacket
+import net.minecraft.network.protocol.game.ServerboundSetCreativeModeSlotPacket
+
+object NewItemsPacketSetCreativeSlot : PacketListener {
+    override fun onReceive(event: PacketEvent) {
+        val packet = event.packet.handle as? ServerboundSetCreativeModeSlotPacket ?: return
+
+        Display.revert(packet.itemStack.asBukkitStack())
+
+        event.player.lastDisplayFrame = DisplayFrame.EMPTY
+    }
+}

eco-core/core-nms/v1_21_5/build.gradle.kts

@@ -0,0 +1,52 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+plugins {
+    id("io.papermc.paperweight.userdev")
+}
+
+group = "com.willfp"
+version = rootProject.version
+
+dependencies {
+    implementation(project(":eco-core:core-nms:modern"))
+    implementation(project(":eco-core:core-nms:common"))
+    paperweight.paperDevBundle("1.21.5-R0.1-SNAPSHOT")
+
+    implementation("net.kyori:adventure-text-minimessage:4.11.0") {
+        version {
+            strictly("4.11.0")
+        }
+        exclude(group = "net.kyori", module = "adventure-api")
+    }
+}
+
+tasks {
+    build {
+        dependsOn(reobfJar)
+    }
+
+    reobfJar {
+        mustRunAfter(shadowJar)
+    }
+
+    shadowJar {
+        relocate(
+            "com.willfp.eco.internal.spigot.proxy.common",
+            "com.willfp.eco.internal.spigot.proxy.v1_21_5.common"
+        )
+        relocate(
+            "net.kyori.adventure.text.minimessage",
+            "com.willfp.eco.internal.spigot.proxy.v1_21_5.minimessage"
+        )
+    }
+
+    compileJava {
+        options.release.set(21)
+    }
+
+    compileKotlin {
+        compilerOptions {
+            jvmTarget.set(JvmTarget.JVM_21)
+        }
+    }
+}

eco-core/core-nms/v1_21_5/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_5/BukkitCommands.kt

@@ -0,0 +1,35 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_5
+
+import com.willfp.eco.core.command.PluginCommandBase
+import com.willfp.eco.internal.spigot.proxy.BukkitCommandsProxy
+import org.bukkit.Bukkit
+import org.bukkit.command.Command
+import org.bukkit.command.SimpleCommandMap
+import org.bukkit.craftbukkit.CraftServer
+import java.lang.reflect.Field
+
+class BukkitCommands : BukkitCommandsProxy {
+    private val knownCommandsField: Field by lazy {
+        SimpleCommandMap::class.java.getDeclaredField("knownCommands")
+            .apply {
+                isAccessible = true
+            }
+    }
+
+    @Suppress("UNCHECKED_CAST")
+    private val knownCommands: MutableMap<String, Command>
+        get() = knownCommandsField.get(getCommandMap()) as MutableMap<String, Command>
+
+    override fun getCommandMap(): SimpleCommandMap {
+        return (Bukkit.getServer() as CraftServer).commandMap
+    }
+
+    override fun syncCommands() {
+        (Bukkit.getServer() as CraftServer).syncCommands()
+    }
+
+    override fun unregisterCommand(command: PluginCommandBase) {
+        knownCommands.remove(command.name)
+        knownCommands.remove("${command.plugin.name.lowercase()}:${command.name}")
+    }
+}

eco-core/core-nms/v1_21_5/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_5/CommonsInitializer.kt

@@ -0,0 +1,171 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_5
+
+import com.willfp.eco.core.EcoPlugin
+import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
+import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
+import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
+import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.json.JSONComponentSerializer
+import net.minecraft.core.component.DataComponents
+import net.minecraft.core.registries.BuiltInRegistries
+import net.minecraft.nbt.CompoundTag
+import net.minecraft.nbt.Tag
+import net.minecraft.resources.ResourceLocation
+import net.minecraft.server.level.ServerPlayer
+import net.minecraft.world.entity.PathfinderMob
+import net.minecraft.world.item.Item
+import org.bukkit.Bukkit
+import org.bukkit.Material
+import org.bukkit.NamespacedKey
+import org.bukkit.craftbukkit.CraftServer
+import org.bukkit.craftbukkit.entity.CraftEntity
+import org.bukkit.craftbukkit.entity.CraftMob
+import org.bukkit.craftbukkit.entity.CraftPlayer
+import org.bukkit.craftbukkit.inventory.CraftItemStack
+import org.bukkit.craftbukkit.inventory.CraftMetaArmor
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataContainer
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataTypeRegistry
+import org.bukkit.craftbukkit.util.CraftMagicNumbers
+import org.bukkit.craftbukkit.util.CraftNamespacedKey
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Mob
+import org.bukkit.entity.Player
+import org.bukkit.inventory.ItemStack
+import org.bukkit.persistence.PersistentDataContainer
+import java.lang.reflect.Field
+
+class CommonsInitializer : CommonsInitializerProxy {
+    override fun init(plugin: EcoPlugin) {
+        CommonsProvider.setIfNeeded(CommonsProviderImpl)
+        plugin.onEnable {
+            plugin.eventManager.registerListener(PacketInjectorListener)
+        }
+    }
+
+    object CommonsProviderImpl : CommonsProvider {
+        private val cisHandle: Field = CraftItemStack::class.java.getDeclaredField("handle").apply {
+            isAccessible = true
+        }
+
+        private val pdcRegsitry = CraftMetaArmor::class.java
+            .superclass // Access CraftMetaItem
+            .getDeclaredField("DATA_TYPE_REGISTRY")
+            .apply { isAccessible = true }
+            .get(null) as CraftPersistentDataTypeRegistry
+
+        override val nbtTagString = 8
+
+        override fun toPathfinderMob(mob: Mob): PathfinderMob? {
+            val craft = mob as? CraftMob ?: return null
+            return craft.handle as? PathfinderMob
+        }
+
+        override fun toResourceLocation(namespacedKey: NamespacedKey): ResourceLocation =
+            CraftNamespacedKey.toMinecraft(namespacedKey)
+
+        override fun asNMSStack(itemStack: ItemStack): net.minecraft.world.item.ItemStack {
+            return if (itemStack !is CraftItemStack) {
+                CraftItemStack.asNMSCopy(itemStack)
+            } else {
+                cisHandle[itemStack] as net.minecraft.world.item.ItemStack? ?: CraftItemStack.asNMSCopy(itemStack)
+            }
+        }
+
+        override fun asBukkitStack(itemStack: net.minecraft.world.item.ItemStack): ItemStack {
+            return CraftItemStack.asCraftMirror(itemStack)
+        }
+
+        override fun mergeIfNeeded(itemStack: ItemStack, nmsStack: net.minecraft.world.item.ItemStack) {
+            if (itemStack !is CraftItemStack) {
+                itemStack.itemMeta = CraftItemStack.asCraftMirror(nmsStack).itemMeta
+            }
+        }
+
+        override fun toBukkitEntity(entity: net.minecraft.world.entity.LivingEntity): LivingEntity? =
+            CraftEntity.getEntity(Bukkit.getServer() as CraftServer, entity) as? LivingEntity
+
+        override fun makePdc(tag: CompoundTag, base: Boolean): PersistentDataContainer {
+            fun emptyPdc(): CraftPersistentDataContainer = CraftPersistentDataContainer(pdcRegsitry)
+
+            fun CompoundTag?.toPdc(): PersistentDataContainer {
+                val pdc = emptyPdc()
+                this ?: return pdc
+                val keys = this.keySet()
+                for (key in keys) {
+                    pdc.put(key, this[key])
+                }
+
+                return pdc
+            }
+
+            return if (base) {
+                tag.toPdc()
+            } else {
+                if (tag.contains("PublicBukkitValues")) {
+                    tag.getCompound("PublicBukkitValues").get().toPdc()
+                } else {
+                    emptyPdc()
+                }
+            }
+        }
+
+        override fun setPdc(
+            tag: CompoundTag,
+            pdc: PersistentDataContainer?,
+            item: net.minecraft.world.item.ItemStack?
+        ) {
+            fun CraftPersistentDataContainer.toTag(): CompoundTag {
+                val compound = CompoundTag()
+                val rawPublicMap: Map<String, Tag> = this.raw
+                for ((key, value) in rawPublicMap) {
+                    compound.put(key, value)
+                }
+
+                return compound
+            }
+
+            val container = when (pdc) {
+                is CraftPersistentDataContainer? -> pdc
+                else -> null
+            }
+
+            if (item != null) {
+                if (container != null && !container.isEmpty) {
+                    for (key in tag.keySet()) {
+                        tag.remove(key)
+                    }
+
+                    tag.merge(container.toTag())
+                } else {
+                    item.remove(DataComponents.CUSTOM_DATA)
+                }
+            } else {
+                if (container != null && !container.isEmpty) {
+                    tag.put("PublicBukkitValues", container.toTag())
+                } else {
+                    tag.remove("PublicBukkitValues")
+                }
+            }
+        }
+
+        override fun materialToItem(material: Material): Item =
+            BuiltInRegistries.ITEM.getOptional(material.key.toResourceLocation())
+                .orElseThrow { IllegalArgumentException("Material is not item!") }
+
+        override fun itemToMaterial(item: Item) =
+            Material.getMaterial(BuiltInRegistries.ITEM.getKey(item).path.uppercase())
+                ?: throw IllegalArgumentException("Invalid material!")
+
+        override fun toNMS(player: Player): ServerPlayer {
+            return (player as CraftPlayer).handle
+        }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = JSONComponentSerializer.json().serialize(component)
+            val holderLookupProvider = (Bukkit.getServer() as CraftServer).server.registryAccess()
+
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json, holderLookupProvider)!!
+        }
+    }
+}

eco-core/core-nms/v1_21_5/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_5/DisplayName.kt

@@ -0,0 +1,57 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_5
+
+import com.willfp.eco.core.packet.Packet
+import com.willfp.eco.core.packet.sendPacket
+import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import net.kyori.adventure.text.Component
+import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
+import net.minecraft.network.syncher.EntityDataAccessor
+import net.minecraft.network.syncher.SynchedEntityData
+import net.minecraft.world.entity.Entity
+import org.bukkit.craftbukkit.entity.CraftLivingEntity
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Player
+import java.util.Optional
+
+@Suppress("UNCHECKED_CAST")
+class DisplayName : DisplayNameProxy {
+    private val displayNameAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[2]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Optional<net.minecraft.network.chat.Component>>
+
+    private val customNameVisibleAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[3]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Boolean>
+
+    override fun setClientsideDisplayName(
+        entity: LivingEntity,
+        player: Player,
+        displayName: Component,
+        visible: Boolean
+    ) {
+        if (entity !is CraftLivingEntity) {
+            return
+        }
+
+        val nmsComponent = displayName.toNMS()
+
+        val nmsEntity = entity.handle
+
+        val packet = ClientboundSetEntityDataPacket(
+            nmsEntity.id,
+            listOf(
+                SynchedEntityData.DataValue.create(displayNameAccessor, Optional.of(nmsComponent)),
+                SynchedEntityData.DataValue.create(customNameVisibleAccessor, visible)
+            )
+        )
+
+        player.sendPacket(Packet(packet))
+    }
+}

eco-core/core-nms/v1_21_5/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_5/DummyEntityFactory.kt

@@ -0,0 +1,15 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_5
+
+import com.willfp.eco.internal.entities.EcoDummyEntity
+import com.willfp.eco.internal.spigot.proxy.DummyEntityFactoryProxy
+import org.bukkit.Location
+import org.bukkit.craftbukkit.CraftWorld
+import org.bukkit.entity.Entity
+import org.bukkit.entity.Zombie
+
+class DummyEntityFactory : DummyEntityFactoryProxy {
+    override fun createDummyEntity(location: Location): Entity {
+        val world = location.world as CraftWorld
+        return EcoDummyEntity(world.createEntity(location, Zombie::class.java))
+    }
+}

eco-core/core-nms/v1_21_5/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_21_5/EntityControllerFactory.kt

@@ -0,0 +1,12 @@
+package com.willfp.eco.internal.spigot.proxy.v1_21_5
+
+import com.willfp.eco.core.entities.ai.EntityController
+import com.willfp.eco.internal.spigot.proxy.EntityControllerFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.v1_21_5.entity.EcoEntityController
+import org.bukkit.entity.Mob
+
+class EntityControllerFactory : EntityControllerFactoryProxy {
+    override fun <T : Mob> createEntityController(entity: T): EntityController<T> {
+        return EcoEntityController(entity)
+    }
+}