Bump version to 5.3.5 for release

* Some overall code health improvement
* Spigot BlockState handling optimization

.github/workflows/ci.yml

@@ -15,9 +15,9 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
-      - uses: actions/setup-java@v5
+      - uses: actions/setup-java@v6
         with:
           distribution: 'temurin'
           java-version: '25'

.github/workflows/draft_release.yml

@@ -20,7 +20,7 @@ jobs:
 
       - name: Create Release
         id: create-release
-        uses: softprops/action-gh-release@v3.0.0
+        uses: softprops/action-gh-release@v3.0.3
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:

.github/workflows/resource_pack_ci.yml

@@ -13,7 +13,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Build resource pack
         id: upload-resource-pack

api/src/main/java/com/lishid/openinv/IOpenInv.java

@@ -24,8 +24,8 @@ import org.bukkit.Bukkit;
 import org.bukkit.OfflinePlayer;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.InventoryView;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.UUID;
 import java.util.logging.Logger;
@@ -33,6 +33,7 @@ import java.util.logging.Logger;
 /**
  * Interface defining behavior for the OpenInv plugin.
  */
+@NullMarked
 public interface IOpenInv {
 
   /**
@@ -76,7 +77,7 @@ public interface IOpenInv {
    * @return the active implementation for the server version
    * @throws IllegalStateException if the server version is unsupported
    */
-  @NotNull IAnySilentContainer getAnySilentContainer();
+  IAnySilentContainer getAnySilentContainer();
 
   /**
    * Get whether a user has AnyContainer mode enabled.
@@ -84,7 +85,7 @@ public interface IOpenInv {
    * @param offline the user to obtain the state of
    * @return true if AnyContainer mode is enabled
    */
-  boolean getAnyContainerStatus(@NotNull OfflinePlayer offline);
+  boolean getAnyContainerStatus(OfflinePlayer offline);
 
   /**
    * Set whether a user has AnyContainer mode enabled.
@@ -92,7 +93,7 @@ public interface IOpenInv {
    * @param offline the user to set the state of
    * @param status the state of the mode
    */
-  void setAnyContainerStatus(@NotNull OfflinePlayer offline, boolean status);
+  void setAnyContainerStatus(OfflinePlayer offline, boolean status);
 
   /**
    * Get whether a user has SilentContainer mode enabled.
@@ -100,7 +101,7 @@ public interface IOpenInv {
    * @param offline the user to obtain the state of
    * @return true if SilentContainer mode is enabled
    */
-  boolean getSilentContainerStatus(@NotNull OfflinePlayer offline);
+  boolean getSilentContainerStatus(OfflinePlayer offline);
 
   /**
    * Set whether a user has SilentContainer mode enabled.
@@ -108,7 +109,7 @@ public interface IOpenInv {
    * @param offline the user to set the state of
    * @param status the state of the mode
    */
-  void setSilentContainerStatus(@NotNull OfflinePlayer offline, boolean status);
+  void setSilentContainerStatus(OfflinePlayer offline, boolean status);
 
   /**
    * Get an {@link ISpecialEnderChest} for a user.
@@ -119,8 +120,8 @@ public interface IOpenInv {
    * @throws IllegalStateException if the server version is unsupported
    * @throws InstantiationException if there was an issue creating the inventory
    */
-  @NotNull ISpecialEnderChest getSpecialEnderChest(
-      @NotNull Player player,
+  ISpecialEnderChest getSpecialEnderChest(
+      Player player,
       boolean online
   ) throws InstantiationException;
 
@@ -133,8 +134,8 @@ public interface IOpenInv {
    * @throws IllegalStateException if the server version is unsupported
    * @throws InstantiationException if there was an issue creating the inventory
    */
-  @NotNull ISpecialPlayerInventory getSpecialInventory(
-      @NotNull Player player,
+  ISpecialPlayerInventory getSpecialInventory(
+      Player player,
       boolean online
   ) throws InstantiationException;
 
@@ -142,7 +143,7 @@ public interface IOpenInv {
    * @deprecated Use {@link #openInventory(Player, ISpecialInventory, boolean)}
    */
   @Deprecated(forRemoval = true, since = "5.2.0")
-  @Nullable InventoryView openInventory(@NotNull Player player, @NotNull ISpecialInventory inventory);
+  @Nullable InventoryView openInventory(Player player, ISpecialInventory inventory);
 
   /**
    * Open an {@link ISpecialInventory} for a {@link Player}.
@@ -152,7 +153,7 @@ public interface IOpenInv {
    * @param viewOnly whether the inventory should be view-only
    * @return the resulting {@link InventoryView}
    */
-  @Nullable InventoryView openInventory(@NotNull Player player, @NotNull ISpecialInventory inventory, boolean viewOnly);
+  @Nullable InventoryView openInventory(Player player, ISpecialInventory inventory, boolean viewOnly);
 
   /**
    * Check if a {@link Player} is currently loaded by OpenInv.
@@ -161,7 +162,7 @@ public interface IOpenInv {
    * @return whether the {@code Player} is loaded
    * @since 4.2.0
    */
-  boolean isPlayerLoaded(@NotNull UUID playerUuid);
+  boolean isPlayerLoaded(UUID playerUuid);
 
   /**
    * Load a {@link Player} from an {@link OfflinePlayer}. If the user has not played before or the default world for
@@ -171,7 +172,7 @@ public interface IOpenInv {
    * @return the loaded {@code Player}
    * @throws IllegalStateException if the server version is unsupported
    */
-  @Nullable Player loadPlayer(@NotNull final OfflinePlayer offline);
+  @Nullable Player loadPlayer(final OfflinePlayer offline);
 
   /**
    * Match an existing {@link OfflinePlayer}. If the name is a {@link UUID#toString() UUID string}, this will only
@@ -184,14 +185,14 @@ public interface IOpenInv {
    * @param name the string to match
    * @return the user with the closest matching name
    */
-  @Nullable OfflinePlayer matchPlayer(@NotNull String name);
+  @Nullable OfflinePlayer matchPlayer(String name);
 
   /**
    * Forcibly close inventories of and unload any cached data for a user.
    *
    * @param offline the {@link OfflinePlayer} to unload
    */
-  void unload(@NotNull OfflinePlayer offline);
+  void unload(OfflinePlayer offline);
 
   Logger getLogger();
 

api/src/main/java/com/lishid/openinv/event/OpenPlayerSaveEvent.java

@@ -5,11 +5,12 @@ import com.lishid.openinv.internal.ISpecialInventory;
 import org.bukkit.entity.Player;
 import org.bukkit.event.HandlerList;
 import org.jetbrains.annotations.ApiStatus;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * Event fired before OpenInv saves a player's data when closing an {@link ISpecialInventory}.
  */
+@NullMarked
 public class OpenPlayerSaveEvent extends PlayerSaveEvent {
 
   private static final HandlerList HANDLERS = new HandlerList();
@@ -26,10 +27,11 @@ public class OpenPlayerSaveEvent extends PlayerSaveEvent {
    */
   @RestrictedApi(
       explanation = "Constructor is not considered part of the API and may be subject to change.",
+      link = "",
       allowedOnPath = ".*/com/lishid/openinv/event/OpenEvents.java"
   )
   @ApiStatus.Internal
-  OpenPlayerSaveEvent(@NotNull Player player, @NotNull ISpecialInventory inventory) {
+  OpenPlayerSaveEvent(Player player, ISpecialInventory inventory) {
     super(player);
     this.inventory = inventory;
   }
@@ -39,11 +41,10 @@ public class OpenPlayerSaveEvent extends PlayerSaveEvent {
    *
    * @return the special inventory
    */
-  public @NotNull ISpecialInventory getInventory() {
+  public ISpecialInventory getInventory() {
     return inventory;
   }
 
-  @NotNull
   @Override
   public HandlerList getHandlers() {
     return HANDLERS;

api/src/main/java/com/lishid/openinv/event/PlayerSaveEvent.java

@@ -7,11 +7,12 @@ import org.bukkit.event.Cancellable;
 import org.bukkit.event.HandlerList;
 import org.bukkit.event.player.PlayerEvent;
 import org.jetbrains.annotations.ApiStatus;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * Event fired before a {@link Player} loaded via OpenInv is saved.
  */
+@NullMarked
 public class PlayerSaveEvent extends PlayerEvent implements Cancellable {
 
   private static final HandlerList HANDLERS = new HandlerList();
@@ -27,10 +28,11 @@ public class PlayerSaveEvent extends PlayerEvent implements Cancellable {
    */
   @RestrictedApi(
       explanation = "Constructor is not considered part of the API and may be subject to change.",
+      link = "",
       allowedOnPath = ".*/com/lishid/openinv/event/(OpenPlayerSaveEvent|OpenEvents).java"
   )
   @ApiStatus.Internal
-  PlayerSaveEvent(@NotNull Player player) {
+  PlayerSaveEvent(Player player) {
     super(player);
   }
 
@@ -54,7 +56,6 @@ public class PlayerSaveEvent extends PlayerEvent implements Cancellable {
     this.cancelled = cancel;
   }
 
-  @NotNull
   @Override
   public HandlerList getHandlers() {
     return HANDLERS;

api/src/main/java/com/lishid/openinv/event/PlayerToggledEvent.java

@@ -5,27 +5,29 @@ import com.lishid.openinv.util.setting.PlayerToggle;
 import org.bukkit.event.Event;
 import org.bukkit.event.HandlerList;
 import org.jetbrains.annotations.ApiStatus;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.UUID;
 
 /**
  * Event fired after OpenInv modifies a toggleable setting for a player.
  */
+@NullMarked
 public class PlayerToggledEvent extends Event {
 
   private static final HandlerList HANDLERS = new HandlerList();
 
-  private final @NotNull PlayerToggle toggle;
-  private final @NotNull UUID uuid;
+  private final PlayerToggle toggle;
+  private final UUID uuid;
   private final boolean enabled;
 
   @RestrictedApi(
       explanation = "Constructor is not considered part of the API and may be subject to change.",
+      link = "",
       allowedOnPath = ".*/com/lishid/openinv/event/OpenEvents.java"
   )
   @ApiStatus.Internal
-  PlayerToggledEvent(@NotNull PlayerToggle toggle, @NotNull UUID uuid, boolean enabled) {
+  PlayerToggledEvent(PlayerToggle toggle, UUID uuid, boolean enabled) {
     this.toggle = toggle;
     this.uuid = uuid;
     this.enabled = enabled;
@@ -36,7 +38,7 @@ public class PlayerToggledEvent extends Event {
    *
    * @return the toggle
    */
-  public @NotNull PlayerToggle getToggle() {
+  public PlayerToggle getToggle() {
     return toggle;
   }
 
@@ -45,7 +47,7 @@ public class PlayerToggledEvent extends Event {
    *
    * @return the player ID
    */
-  public @NotNull UUID getPlayerId() {
+  public UUID getPlayerId() {
     return uuid;
   }
 
@@ -58,7 +60,6 @@ public class PlayerToggledEvent extends Event {
     return enabled;
   }
 
-  @NotNull
   @Override
   public HandlerList getHandlers() {
     return HANDLERS;

api/src/main/java/com/lishid/openinv/internal/IAnySilentContainer.java

@@ -26,8 +26,10 @@ import org.bukkit.entity.Player;
 import org.bukkit.inventory.Inventory;
 import org.bukkit.inventory.InventoryHolder;
 import org.bukkit.util.BoundingBox;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
+@NullMarked
 public interface IAnySilentContainer {
 
   /**
@@ -39,14 +41,14 @@ public interface IAnySilentContainer {
    * @param block  the {@link Block} of the container
    * @return true if the container can be opened
    */
-  boolean activateContainer(@NotNull Player player, boolean silent, @NotNull Block block);
+  boolean activateContainer(Player player, boolean silent, Block block);
 
   /**
    * Perform operations required to close the current container silently.
    *
    * @param player the {@link Player} closing a container
    */
-  void deactivateContainer(@NotNull Player player);
+  void deactivateContainer(Player player);
 
   /**
    * Check if the container at the given coordinates is blocked.
@@ -54,7 +56,7 @@ public interface IAnySilentContainer {
    * @param block the {@link Block} of the container
    * @return true if the container is blocked
    */
-  boolean isAnyContainerNeeded(@NotNull Block block);
+  boolean isAnyContainerNeeded(Block block);
 
   /**
    * Check if a shulker box block cannot be opened under ordinary circumstances.
@@ -62,7 +64,7 @@ public interface IAnySilentContainer {
    * @param shulkerBox the shulker box block
    * @return whether the container is blocked
    */
-  default boolean isShulkerBlocked(@NotNull Block shulkerBox) {
+  default boolean isShulkerBlocked(Block shulkerBox) {
     Directional directional = (Directional) shulkerBox.getBlockData();
     BlockFace facing = directional.getFacing();
     // Construct a new 1-block bounding box at the origin.
@@ -81,7 +83,7 @@ public interface IAnySilentContainer {
    * @param chest the chest block
    * @return whether the container is blocked
    */
-  default boolean isChestBlocked(@NotNull Block chest) {
+  default boolean isChestBlocked(Block chest) {
     org.bukkit.block.Block relative = chest.getRelative(0, 1, 0);
     return relative.getType().isOccluding()
         || !chest.getWorld().getNearbyEntities(BoundingBox.of(relative), Cat.class::isInstance).isEmpty();
@@ -93,7 +95,7 @@ public interface IAnySilentContainer {
    * @param block the potential container
    * @return true if the type is a supported container
    */
-  boolean isAnySilentContainer(@NotNull Block block);
+  boolean isAnySilentContainer(Block block);
 
   /**
    * Check if the given {@link BlockState} is a container which can be unblocked or silenced.
@@ -101,7 +103,7 @@ public interface IAnySilentContainer {
    * @param blockState the potential container
    * @return true if the type is a supported container
    */
-  default boolean isAnySilentContainer(@NotNull BlockState blockState) {
+  default boolean isAnySilentContainer(BlockState blockState) {
     return (blockState instanceof InventoryHolder holder && isAnySilentContainer(holder))
         || blockState instanceof EnderChest;
   }
@@ -112,7 +114,7 @@ public interface IAnySilentContainer {
    * @param holder the potential container
    * @return true if the type is a supported container
    */
-  default boolean isAnySilentContainer(@NotNull InventoryHolder holder) {
+  default boolean isAnySilentContainer(@Nullable InventoryHolder holder) {
     return holder instanceof org.bukkit.block.EnderChest
         || holder instanceof org.bukkit.block.Chest
         || holder instanceof org.bukkit.block.DoubleChest
@@ -126,6 +128,6 @@ public interface IAnySilentContainer {
    * @param inventory the potential container inventory
    * @return true if the type is a supported container
    */
-  boolean isAnySilentContainer(@NotNull Inventory inventory);
+  boolean isAnySilentContainer(Inventory inventory);
 
 }

api/src/main/java/com/lishid/openinv/internal/ISpecialEnderChest.java

@@ -17,15 +17,16 @@
 package com.lishid.openinv.internal;
 
 import org.bukkit.event.inventory.InventoryType;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * An {@link ISpecialInventory} representing an ender chest.
  */
+@NullMarked
 public interface ISpecialEnderChest extends ISpecialInventory {
 
   @Override
-  default @NotNull InventoryType getBukkitType() {
+  default InventoryType getBukkitType() {
     return InventoryType.ENDER_CHEST;
   }
 

api/src/main/java/com/lishid/openinv/internal/ISpecialInventory.java

@@ -20,11 +20,12 @@ import org.bukkit.entity.HumanEntity;
 import org.bukkit.entity.Player;
 import org.bukkit.event.inventory.InventoryType;
 import org.bukkit.inventory.Inventory;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * Interface defining behavior for special inventories backed by other inventories' content listings.
  */
+@NullMarked
 public interface ISpecialInventory {
 
   /**
@@ -32,21 +33,21 @@ public interface ISpecialInventory {
    *
    * @return the Bukkit inventory
    */
-  @NotNull Inventory getBukkitInventory();
+  Inventory getBukkitInventory();
 
   /**
    * Get the {@link InventoryType} corresponding to this {@code ISpecialInventory}.
    *
    * @return the type of Bukkit inventory
    */
-  @NotNull InventoryType getBukkitType();
+  InventoryType getBukkitType();
 
   /**
    * Set the owning {@link Player} instance to a newly-joined user.
    *
    * @param player the user coming online
    */
-  void setPlayerOnline(@NotNull Player player);
+  void setPlayerOnline(Player player);
 
   /**
    * Mark the owner of the inventory offline.
@@ -70,6 +71,6 @@ public interface ISpecialInventory {
    *
    * @return the {@link HumanEntity} who owns the inventory
    */
-  @NotNull HumanEntity getPlayer();
+  HumanEntity getPlayer();
 
 }

api/src/main/java/com/lishid/openinv/internal/ISpecialPlayerInventory.java

@@ -17,15 +17,16 @@
 package com.lishid.openinv.internal;
 
 import org.bukkit.event.inventory.InventoryType;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * An {@link ISpecialInventory} representing a player inventory.
  */
+@NullMarked
 public interface ISpecialPlayerInventory extends ISpecialInventory {
 
   @Override
-  default @NotNull InventoryType getBukkitType() {
+  default InventoryType getBukkitType() {
     return InventoryType.PLAYER;
   }
 

api/src/main/java/com/lishid/openinv/util/InventoryAccess.java

@@ -22,14 +22,15 @@ import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.internal.ISpecialPlayerInventory;
 import org.bukkit.inventory.Inventory;
 import org.jetbrains.annotations.ApiStatus;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.function.BiFunction;
 
+@NullMarked
 public final class InventoryAccess {
 
-  private static @Nullable BiFunction<Inventory, Class<? extends ISpecialInventory>, ISpecialInventory> provider;
+  private static @Nullable BiFunction<Inventory, Class<? extends ISpecialInventory>, @Nullable ISpecialInventory> provider;
 
   public static boolean isUsable() {
     return provider != null;
@@ -41,7 +42,7 @@ public final class InventoryAccess {
    * @param inventory the Bukkit inventory
    * @return true if backed by the correct implementation
    */
-  public static boolean isPlayerInventory(@NotNull Inventory inventory) {
+  public static boolean isPlayerInventory(Inventory inventory) {
     return getPlayerInventory(inventory) != null;
   }
 
@@ -52,7 +53,7 @@ public final class InventoryAccess {
    * @param inventory the Bukkit inventory
    * @return the backing implementation if available
    */
-  public static @Nullable ISpecialPlayerInventory getPlayerInventory(@NotNull Inventory inventory) {
+  public static @Nullable ISpecialPlayerInventory getPlayerInventory(Inventory inventory) {
     return provider == null ? null : (ISpecialPlayerInventory) provider.apply(inventory, ISpecialPlayerInventory.class);
   }
 
@@ -62,7 +63,7 @@ public final class InventoryAccess {
    * @param inventory the Bukkit inventory
    * @return true if backed by the correct implementation
    */
-  public static boolean isEnderChest(@NotNull Inventory inventory) {
+  public static boolean isEnderChest(Inventory inventory) {
     return getEnderChest(inventory) != null;
   }
 
@@ -73,7 +74,7 @@ public final class InventoryAccess {
    * @param inventory the Bukkit inventory
    * @return the backing implementation if available
    */
-  public static @Nullable ISpecialEnderChest getEnderChest(@NotNull Inventory inventory) {
+  public static @Nullable ISpecialEnderChest getEnderChest(Inventory inventory) {
     return provider == null ? null : (ISpecialEnderChest) provider.apply(inventory, ISpecialEnderChest.class);
   }
 
@@ -84,17 +85,18 @@ public final class InventoryAccess {
    * @param inventory the Bukkit inventory
    * @return the backing implementation if available
    */
-  public static @Nullable ISpecialInventory getInventory(@NotNull Inventory inventory) {
+  public static @Nullable ISpecialInventory getInventory(Inventory inventory) {
     return provider == null ? null : provider.apply(inventory, ISpecialInventory.class);
   }
 
   @RestrictedApi(
       explanation = "Not part of the API.",
+      link = "",
       allowedOnPath = ".*/com/lishid/openinv/util/InternalAccessor.java"
   )
   @ApiStatus.Internal
   static void setProvider(
-      @Nullable BiFunction<Inventory, Class<? extends ISpecialInventory>, ISpecialInventory> provider
+      @Nullable BiFunction<Inventory, Class<? extends ISpecialInventory>, @Nullable ISpecialInventory> provider
   ) {
     InventoryAccess.provider = provider;
   }

api/src/main/java/com/lishid/openinv/util/Permissions.java

@@ -17,7 +17,7 @@
 package com.lishid.openinv.util;
 
 import org.bukkit.permissions.Permissible;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * An enum containing all permissions directly checked by OpenInv.
@@ -25,6 +25,7 @@ import org.jetbrains.annotations.NotNull;
  * <p>Note that this is not an exhaustive list! This does not contain
  * all permissions managed by Bukkit, largely parent nodes.</p>
  */
+@NullMarked
 public enum Permissions {
 
   /// Permission to open one's own inventory.
@@ -121,7 +122,7 @@ public enum Permissions {
    * @param permissible the Permissible
    * @return true if the permission is granted
    */
-  public boolean hasPermission(@NotNull Permissible permissible) {
+  public boolean hasPermission(Permissible permissible) {
     return permissible.hasPermission(permission);
   }
 

api/src/main/java/com/lishid/openinv/util/setting/PlayerToggle.java

@@ -1,13 +1,14 @@
 package com.lishid.openinv.util.setting;
 
 import org.bukkit.entity.Player;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.UUID;
 
 /**
  * A per-player setting that may be enabled or disabled.
  */
+@NullMarked
 public interface PlayerToggle {
 
   /**
@@ -15,7 +16,7 @@ public interface PlayerToggle {
    *
    * @return the setting name
    */
-  @NotNull String getName();
+  String getName();
 
   /**
    * Get the state of the toggle for a particular player ID.
@@ -23,7 +24,7 @@ public interface PlayerToggle {
    * @param uuid the player ID
    * @return true if the setting is enabled
    */
-  boolean is(@NotNull UUID uuid);
+  boolean is(UUID uuid);
 
   /**
    * Get the state of the toggle for a particular {@link Player},
@@ -32,7 +33,7 @@ public interface PlayerToggle {
    * @param player the player
    * @return true if the setting is enabled and the player has the required permissions
    */
-  boolean is(@NotNull Player player);
+  boolean is(Player player);
 
   /**
    * Set the state of the toggle for a particular player ID.
@@ -41,6 +42,6 @@ public interface PlayerToggle {
    * @param enabled whether the setting is enabled
    * @return true if the setting changed as a result of being set
    */
-  boolean set(@NotNull UUID uuid, boolean enabled);
+  boolean set(UUID uuid, boolean enabled);
 
 }

api/src/main/java/com/lishid/openinv/util/setting/PlayerToggles.java

@@ -2,9 +2,9 @@ package com.lishid.openinv.util.setting;
 
 import com.lishid.openinv.util.Permissions;
 import org.bukkit.entity.Player;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 import org.jetbrains.annotations.UnmodifiableView;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -18,19 +18,20 @@ import java.util.UUID;
 /**
  * Utility class containing all of OpenInv's {@link PlayerToggle PlayerToggles}.
  */
+@NullMarked
 public final class PlayerToggles {
 
   private static final Map<String, PlayerToggle> TOGGLES = new HashMap<>();
   private static final PlayerToggle ANY = add(new MemoryToggle("AnyContainer") {
     @Override
-    public boolean is(@NotNull Player player) {
+    public boolean is(Player player) {
       return is(player.getUniqueId())
           && (Permissions.CONTAINER_ANY.hasPermission(player) || Permissions.CONTAINER_ANY_USE.hasPermission(player));
     }
   });
   private static final PlayerToggle SILENT = add(new MemoryToggle("SilentContainer") {
     @Override
-    public boolean is(@NotNull Player player) {
+    public boolean is(Player player) {
       return is(player.getUniqueId())
           && (Permissions.CONTAINER_SILENT.hasPermission(player) || Permissions.CONTAINER_SILENT_USE.hasPermission(player));
     }
@@ -41,7 +42,7 @@ public final class PlayerToggles {
    *
    * @return the AnyContainer toggle
    */
-  public static @NotNull PlayerToggle any() {
+  public static PlayerToggle any() {
     return ANY;
   }
 
@@ -50,7 +51,7 @@ public final class PlayerToggles {
    *
    * @return the SilentContainer toggle
    */
-  public static @NotNull PlayerToggle silent() {
+  public static PlayerToggle silent() {
     return SILENT;
   }
 
@@ -60,7 +61,7 @@ public final class PlayerToggles {
    * @param toggleName the name of the toggle
    * @return the toggle, or null if no such toggle exists.
    */
-  public static @Nullable PlayerToggle get(@NotNull String toggleName) {
+  public static @Nullable PlayerToggle get(String toggleName) {
     PlayerToggle toggle = TOGGLES.get(toggleName);
     if (toggle == null) {
       toggle = TOGGLES.get(toggleName.toLowerCase(Locale.ENGLISH));
@@ -73,11 +74,11 @@ public final class PlayerToggles {
    *
    * @return a view of all toggles available
    */
-  public static @UnmodifiableView @NotNull Collection<PlayerToggle> get() {
+  public static @UnmodifiableView Collection<PlayerToggle> get() {
     return Collections.unmodifiableCollection(TOGGLES.values());
   }
 
-  private static @NotNull PlayerToggle add(@NotNull PlayerToggle toggle) {
+  private static PlayerToggle add(PlayerToggle toggle) {
     TOGGLES.put(toggle.getName().toLowerCase(Locale.ENGLISH), toggle);
     return toggle;
   }
@@ -88,26 +89,26 @@ public final class PlayerToggles {
 
   private static abstract class MemoryToggle implements PlayerToggle {
 
-    private final @NotNull Set<UUID> enabled;
-    private final @NotNull String name;
+    private final Set<UUID> enabled;
+    private final String name;
 
-    private MemoryToggle(@NotNull String name) {
+    private MemoryToggle(String name) {
       enabled = new HashSet<>();
       this.name = name;
     }
 
     @Override
-    public @NotNull String getName() {
+    public String getName() {
       return this.name;
     }
 
     @Override
-    public boolean is(@NotNull UUID uuid) {
+    public boolean is(UUID uuid) {
       return enabled.contains(uuid);
     }
 
     @Override
-    public boolean set(@NotNull UUID uuid, boolean enabled) {
+    public boolean set(UUID uuid, boolean enabled) {
       if (enabled) {
         return this.enabled.add(uuid);
       } else {

common/src/main/java/com/github/jikoo/openinv/internal/Accessor.java

@@ -0,0 +1,28 @@
+package com.github.jikoo.openinv.internal;
+
+import com.lishid.openinv.internal.IAnySilentContainer;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+public interface Accessor {
+
+  PlayerManager getPlayerManager();
+
+  IAnySilentContainer getAnySilentContainer();
+
+  ISpecialPlayerInventory createPlayerInventory(Player player);
+
+  ISpecialEnderChest createEnderChest(Player player);
+
+  <T extends ISpecialInventory> @Nullable T get(Inventory bukkitInventory, Class<T> clazz);
+
+  void reload(ConfigurationSection config);
+
+}

common/src/main/java/com/github/jikoo/openinv/internal/PlayerManager.java

@@ -14,14 +14,16 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-package com.lishid.openinv.internal;
+package com.github.jikoo.openinv.internal;
 
+import com.lishid.openinv.internal.ISpecialInventory;
 import org.bukkit.OfflinePlayer;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.InventoryView;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
+@NullMarked
 public interface PlayerManager {
 
   /**
@@ -32,14 +34,14 @@ public interface PlayerManager {
    * @param offline the OfflinePlayer
    * @return the Player loaded
    */
-  @Nullable Player loadPlayer(@NotNull OfflinePlayer offline);
+  @Nullable Player loadPlayer(OfflinePlayer offline);
 
   /**
    * Creates a new Player from an existing one that will function slightly better offline.
    *
    * @return the Player
    */
-  @NotNull Player inject(@NotNull Player player);
+  Player inject(Player player);
 
   /**
    * Opens an ISpecialInventory for a Player.
@@ -49,6 +51,6 @@ public interface PlayerManager {
    *
    * @return the InventoryView opened
    */
-  @Nullable InventoryView openInventory(@NotNull Player player, @NotNull ISpecialInventory inventory, boolean viewOnly);
+  @Nullable InventoryView openInventory(Player player, ISpecialInventory inventory, boolean viewOnly);
 
 }

common/src/main/java/com/github/jikoo/openinv/internal/container/AnySilentContainerBase.java

@@ -0,0 +1,107 @@
+package com.github.jikoo.openinv.internal.container;
+
+import com.lishid.openinv.internal.IAnySilentContainer;
+import org.bukkit.block.Barrel;
+import org.bukkit.block.Block;
+import org.bukkit.block.BlockFace;
+import org.bukkit.block.BlockState;
+import org.bukkit.block.EnderChest;
+import org.bukkit.block.ShulkerBox;
+import org.bukkit.block.data.BlockData;
+import org.bukkit.block.data.type.Chest;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.InventoryHolder;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+public abstract class AnySilentContainerBase implements IAnySilentContainer {
+
+  public enum StateType {
+    ENDER_CHEST,
+    SHULKER_BOX,
+    CHEST,
+    BARREL,
+    OTHER
+  }
+
+  @Override
+  public boolean isAnyContainerNeeded(Block block) {
+    return isAnyContainerNeeded(getStateType(block), block);
+  }
+
+  protected boolean isAnyContainerNeeded(StateType material, Block block) {
+    return switch (material) {
+      // Enderchests require a non-occluding block on top to open.
+      case ENDER_CHEST -> block.getRelative(0, 1, 0).getType().isOccluding();
+      // Shulker boxes require half a block clear in the direction they open.
+      case SHULKER_BOX -> isShulkerBlocked(block);
+      // Chests require that the block above not be occluding or occupied by a cat.
+      case CHEST -> isChestBlocked(block);
+      // Barrels need silent but not any. All others unsupported.
+      default -> false;
+    };
+  }
+
+  @Override
+  public boolean isChestBlocked(Block block) {
+    if (IAnySilentContainer.super.isChestBlocked(block)) {
+      return true;
+    }
+
+    BlockData blockData = block.getBlockData();
+    if (!(blockData instanceof Chest chest) || chest.getType() == Chest.Type.SINGLE) {
+      return false;
+    }
+
+    BlockFace relativeFace = switch (chest.getFacing()) {
+      case NORTH -> chest.getType() == Chest.Type.RIGHT ? BlockFace.WEST : BlockFace.EAST;
+      case EAST -> chest.getType() == Chest.Type.RIGHT ? BlockFace.NORTH : BlockFace.SOUTH;
+      case SOUTH -> chest.getType() == Chest.Type.RIGHT ? BlockFace.EAST : BlockFace.WEST;
+      case WEST -> chest.getType() == Chest.Type.RIGHT ? BlockFace.SOUTH : BlockFace.NORTH;
+      default -> BlockFace.SELF;
+    };
+    Block relative = block.getRelative(relativeFace);
+
+    if (relative.getType() != block.getType()) {
+      return false;
+    }
+
+    BlockData relativeData = relative.getBlockData();
+    if (!(relativeData instanceof Chest relativeChest)) {
+      return false;
+    }
+
+    if (relativeChest.getFacing() != chest.getFacing()
+        || relativeChest.getType() != (chest.getType() == Chest.Type.RIGHT ? Chest.Type.LEFT : Chest.Type.RIGHT)) {
+      return false;
+    }
+
+    return IAnySilentContainer.super.isChestBlocked(relative);
+  }
+
+  @Override
+  public boolean isAnySilentContainer(Block block) {
+    return isAnySilentContainer(getState(block));
+  }
+
+  @Override
+  public boolean isAnySilentContainer(Inventory inventory) {
+    return isAnySilentContainer(getHolder(inventory));
+  }
+
+  protected StateType getStateType(Block block) {
+    return switch (getState(block)) {
+      case Barrel ignored -> StateType.BARREL;
+      case EnderChest ignored -> StateType.ENDER_CHEST;
+      case ShulkerBox ignored -> StateType.SHULKER_BOX;
+      case org.bukkit.block.Chest ignored -> StateType.CHEST;
+      default -> StateType.OTHER;
+    };
+  }
+
+  protected abstract BlockState getState(Block block);
+
+  protected abstract @Nullable InventoryHolder getHolder(Inventory inventory);
+
+}

common/src/main/java/com/github/jikoo/openinv/internal/container/InternalOwned.java

@@ -0,0 +1,10 @@
+package com.github.jikoo.openinv.internal.container;
+
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public interface InternalOwned<T> {
+
+  T getOwnerHandle();
+
+}

common/src/main/java/com/github/jikoo/openinv/internal/container/ViewOnly.java

@@ -0,0 +1,4 @@
+package com.github.jikoo.openinv.internal.container;
+
+public interface ViewOnly {
+}

common/src/main/java/com/github/jikoo/openinv/internal/container/slot/Content.java

@@ -1,53 +1,50 @@
-package com.lishid.openinv.internal.paper26_2.container.slot;
+package com.github.jikoo.openinv.internal.container.slot;
 
-import net.minecraft.server.level.ServerPlayer;
-import net.minecraft.world.Container;
-import net.minecraft.world.inventory.Slot;
-import net.minecraft.world.item.ItemStack;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
- * An interface defining behaviors for entries in a {@link Container}. Used to reduce duplicate content reordering.
+ * An interface defining behaviors for entries in a {@link net.minecraft.world.Container Container}. Used to reduce duplicate content reordering.
  */
-public interface Content {
+@NullMarked
+public interface Content<P, I, C, S> {
 
   /**
    * Update internal holder.
    *
    * @param holder the new holder
    */
-  void setHolder(@NotNull ServerPlayer holder);
+  void setHolder(P holder);
 
   /**
    * Get the current item.
    *
    * @return the current item
    */
-  ItemStack get();
+  I get();
 
   /**
    * Remove the current item.
    *
    * @return the current item
    */
-  ItemStack remove();
+  I remove();
 
   /**
    * Remove some of the current item.
    *
    * @return the current item
    */
-  ItemStack removePartial(int amount);
+  I removePartial(int amount);
 
   /**
    * Set the current item. If slot is currently not usable, will drop item instead.
    *
    * @param itemStack the item to set
    */
-  void set(ItemStack itemStack);
+  void set(I itemStack);
 
   /**
-   * Get a {@link Slot} for use in a {@link net.minecraft.world.inventory.AbstractContainerMenu ContainerMenu}. Will
+   * Get a {@link net.minecraft.world.inventory.Slot Slot} for use in a {@link net.minecraft.world.inventory.AbstractContainerMenu ContainerMenu}. Will
    * impose any specific restrictions to insertion or removal.
    *
    * @param container the backing container
@@ -56,7 +53,7 @@ public interface Content {
    * @param y clientside y dimension from top left of inventory, not used
    * @return a menu slot
    */
-  Slot asSlot(Container container, int slot, int x, int y);
+  S asSlot(C container, int slot, int x, int y);
 
   /**
    * Get a loose Bukkit translation of what this slot stores. For example, any slot that drops items at the owner rather

common/src/main/java/com/github/jikoo/openinv/internal/container/slot/InventoryFactory.java

@@ -0,0 +1,35 @@
+package com.github.jikoo.openinv.internal.container.slot;
+
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.ItemStack;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.List;
+import java.util.function.Function;
+
+@NullMarked
+public interface InventoryFactory<P, I, C, S, E> {
+
+  Content<P, I, C, S> newCrafting(P holder, int index);
+
+  Content<P, I, C, S> newCraftingResult(P holder);
+
+  Content<P, I, C, S> newCursor(P holder);
+
+  Content<P, I, C, S> newDrop(P holder);
+
+  Content<P, I, C, S> newEquipment(P holder, E equipmentSlot);
+
+  Content<P, I, C, S> newList(P holder, int index, InventoryType.SlotType slotType, Function<P, List<I>> listSupplier);
+
+  Content<P, I, C, S> newOffHand(P holder);
+
+  Content<P, I, C, S> newViewOnly(P holder);
+
+  Content<P, I, C, S> newViewOnly(P holder, I itemStack);
+
+  S wrapViewOnly(S wrapped);
+
+  ItemStack asBukkitMirror(I itemStack);
+
+}

common/src/main/java/com/github/jikoo/openinv/lang/LanguageManager.java

@@ -1,20 +1,4 @@
-/*
- * Copyright (C) 2011-2022 lishid. All rights reserved.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 3.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-package com.lishid.openinv.util.lang;
+package com.github.jikoo.openinv.lang;
 
 import net.md_5.bungee.api.ChatMessageType;
 import net.md_5.bungee.api.chat.TextComponent;
@@ -25,8 +9,8 @@ import org.bukkit.configuration.ConfigurationSection;
 import org.bukkit.configuration.file.YamlConfiguration;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.Plugin;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.io.BufferedReader;
 import java.io.File;
@@ -44,9 +28,8 @@ import java.util.logging.Level;
 
 /**
  * A simple language manager supporting both custom and bundled languages.
- *
- * @author Jikoo
  */
+@NullMarked
 public class LanguageManager {
 
   private final Plugin plugin;
@@ -54,7 +37,7 @@ public class LanguageManager {
   private final String defaultLocale;
   private final Map<String, YamlConfiguration> locales;
 
-  public LanguageManager(@NotNull Plugin plugin, @NotNull String defaultLocale) {
+  public LanguageManager(Plugin plugin, String defaultLocale) {
     this.plugin = plugin;
     this.defaultLocale = defaultLocale;
     this.locales = new HashMap<>();
@@ -72,7 +55,7 @@ public class LanguageManager {
     getOrLoadLocale(defaultLocale);
   }
 
-  private @NotNull YamlConfiguration getOrLoadLocale(@NotNull String locale) {
+  private YamlConfiguration getOrLoadLocale(String locale) {
     YamlConfiguration loaded = locales.get(locale);
     if (loaded != null) {
       return loaded;
@@ -110,7 +93,7 @@ public class LanguageManager {
     return localeConfig;
   }
 
-  private @NotNull LangLocation bestMatch(@NotNull String locale, @Nullable LangLocation initial) {
+  private LangLocation bestMatch(String locale, @Nullable LangLocation initial) {
     File file = new File(folder, locale + ".yml");
     InputStream bundled = plugin.getResource("locale/" + locale + ".yml");
 
@@ -132,7 +115,7 @@ public class LanguageManager {
     return bestMatch(locale.substring(0, lastSeparator), initial);
   }
 
-  private @NotNull YamlConfiguration loadLocale(@NotNull LangLocation lang) {
+  private YamlConfiguration loadLocale(LangLocation lang) {
     YamlConfiguration localeConfigDefaults;
     if (lang.bundled == null) {
       localeConfigDefaults = new YamlConfiguration();
@@ -195,7 +178,7 @@ public class LanguageManager {
     return localeConfig;
   }
 
-  private void addTranslationFallthrough(@NotNull LangLocation location, @NotNull YamlConfiguration localeConfig) {
+  private void addTranslationFallthrough(LangLocation location, YamlConfiguration localeConfig) {
     YamlConfiguration defaultLocaleConfig = locales.get(defaultLocale);
 
     // Get missing keys. Keys that already have a guess value are not new and don't need to trigger another write.
@@ -222,9 +205,9 @@ public class LanguageManager {
     localeConfig.setDefaults(defaultLocaleConfig);
   }
 
-  private @NotNull List<String> getMissingKeys(
-      @NotNull Configuration configurationDefault,
-      @NotNull Predicate<String> nodeSetPredicate
+  private List<String> getMissingKeys(
+      Configuration configurationDefault,
+      Predicate<String> nodeSetPredicate
   ) {
     List<String> missingKeys = new ArrayList<>();
     for (String key : configurationDefault.getKeys(true)) {
@@ -236,7 +219,7 @@ public class LanguageManager {
     return missingKeys;
   }
 
-  public @Nullable String getValue(@NotNull String key, @Nullable String locale) {
+  public @Nullable String getValue(String key, @Nullable String locale) {
     String value = getOrLoadLocale(locale == null ? defaultLocale : locale.toLowerCase(Locale.ENGLISH)).getString(key);
     if (value == null || value.isBlank()) {
       return null;
@@ -248,9 +231,9 @@ public class LanguageManager {
   }
 
   public @Nullable String getValue(
-      @NotNull String key,
+      String key,
       @Nullable String locale,
-      Replacement @NotNull ... replacements
+      Replacement... replacements
   ) {
     String value = getValue(key, locale);
 
@@ -265,19 +248,19 @@ public class LanguageManager {
     return value;
   }
 
-  public @Nullable String getLocalizedMessage(@NotNull CommandSender sender, @NotNull String key) {
+  public @Nullable String getLocalizedMessage(CommandSender sender, String key) {
     return getValue(key, getLocale(sender));
   }
 
   public @Nullable String getLocalizedMessage(
-      @NotNull CommandSender sender,
-      @NotNull String key,
-      Replacement @NotNull ... replacements
+      CommandSender sender,
+      String key,
+      Replacement... replacements
   ) {
     return getValue(key, getLocale(sender), replacements);
   }
 
-  private @NotNull String getLocale(@NotNull CommandSender sender) {
+  private String getLocale(CommandSender sender) {
     if (sender instanceof Player player) {
       return player.getLocale();
     } else {
@@ -285,7 +268,7 @@ public class LanguageManager {
     }
   }
 
-  public void sendMessage(@NotNull CommandSender sender, @NotNull String key) {
+  public void sendMessage(CommandSender sender, String key) {
     String message = getLocalizedMessage(sender, key);
 
     if (message != null && !message.isEmpty()) {
@@ -293,7 +276,7 @@ public class LanguageManager {
     }
   }
 
-  public void sendMessage(@NotNull CommandSender sender, @NotNull String key, Replacement @NotNull ... replacements) {
+  public void sendMessage(CommandSender sender, String key, Replacement... replacements) {
     String message = getLocalizedMessage(sender, key, replacements);
 
     if (message != null && !message.isEmpty()) {
@@ -301,7 +284,7 @@ public class LanguageManager {
     }
   }
 
-  public void sendSystemMessage(@NotNull Player player, @NotNull String key) {
+  public void sendSystemMessage(Player player, String key) {
     String message = getLocalizedMessage(player, key);
 
     if (message == null) {
@@ -321,6 +304,6 @@ public class LanguageManager {
     player.spigot().sendMessage(ChatMessageType.ACTION_BAR, TextComponent.fromLegacy(message));
   }
 
-  private record LangLocation(@NotNull String locale, @NotNull File file, @Nullable InputStream bundled) {}
+  private record LangLocation(String locale, File file, @Nullable InputStream bundled) {}
 
 }

common/src/main/java/com/github/jikoo/openinv/lang/Replacement.java

@@ -0,0 +1,14 @@
+package com.github.jikoo.openinv.lang;
+
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * A data holder for string replacement in translations.
+ *
+ * @param placeholder the placeholder to be replaced
+ * @param value the value to insert
+ */
+@NullMarked
+public record Replacement(String placeholder, String value) {
+
+}

common/src/main/java/com/github/jikoo/openinv/util/JulLoggerAdapter.java

@@ -1,5 +1,6 @@
-package com.lishid.openinv.util;
+package com.github.jikoo.openinv.util;
 
+import org.jspecify.annotations.NullMarked;
 import org.slf4j.Marker;
 import org.slf4j.helpers.LegacyAbstractLogger;
 import org.slf4j.helpers.MessageFormatter;
@@ -14,6 +15,7 @@ import java.util.logging.Logger;
  * An adapter for wrapping a {@link java.util.logging.Logger} as a {@link org.slf4j.Logger}.
  * <br>Largely based on {@code JDK14LoggerAdapter}, which is not present at runtime.
  */
+@NullMarked
 public class JulLoggerAdapter extends LegacyAbstractLogger implements LocationAwareLogger {
 
   private final Logger wrapped;
@@ -55,22 +57,17 @@ public class JulLoggerAdapter extends LegacyAbstractLogger implements LocationAw
   }
 
   private void addSource(String fqcn, LogRecord logRecord) {
-    // TODO stackwalker?
-    StackTraceElement[] trace = new Throwable().getStackTrace();
-    int maxElements = 12;
-    int lastIgnored = maxElements;
-    // Start from 2; 0 is above and 1 is caller of internal method.
-    for (int i = 2; i < maxElements; ++i) {
-      if (isIgnored(trace[i].getClassName(), fqcn)) {
-        lastIgnored = i;
-      }
-    }
-
-    if (lastIgnored < maxElements - 1) {
-      StackTraceElement caller = trace[lastIgnored + 1];
-      logRecord.setSourceClassName(caller.getClassName());
-      logRecord.setSourceMethodName(caller.getMethodName());
-    }
+    StackWalker.getInstance().walk(stream -> stream
+        // Start at index 2 - this is an internal method, so we want at least the caller's caller.
+        .skip(2)
+        // Walk at maximum 10 frames.
+        .limit(10)
+        .filter(frame -> isIgnored(frame.getClassName(), fqcn))
+        .findFirst()
+    ).ifPresent(frame -> {
+      logRecord.setSourceClassName(frame.getClassName());
+      logRecord.setSourceMethodName(frame.getMethodName());
+    });
   }
 
   private boolean isIgnored(String className, String fqcn) {

common/src/main/java/com/github/jikoo/openinv/util/ReflectionHelper.java

@@ -1,28 +1,14 @@
-/*
- * Copyright (C) 2011-2021 lishid. All rights reserved.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 3.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
+package com.github.jikoo.openinv.util;
 
-package com.lishid.openinv.util;
-
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.lang.reflect.Field;
 
 /**
  * A utility for making reflection easier.
  */
+@NullMarked
 public final class ReflectionHelper {
 
   /**

common/src/main/java/com/lishid/openinv/event/OpenEvents.java

@@ -6,24 +6,25 @@ import org.bukkit.Bukkit;
 import org.bukkit.entity.Player;
 import org.bukkit.event.Cancellable;
 import org.bukkit.event.Event;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.UUID;
 
 /**
  * Construct and call events.
  */
+@NullMarked
 public final class OpenEvents {
 
-  public static boolean saveCancelled(@NotNull Player player) {
+  public static boolean saveCancelled(Player player) {
     return call(new PlayerSaveEvent(player));
   }
 
-  public static boolean saveCancelled(@NotNull ISpecialInventory inventory) {
+  public static boolean saveCancelled(ISpecialInventory inventory) {
     return call(new OpenPlayerSaveEvent((Player) inventory.getPlayer(), inventory));
   }
 
-  public static void notifyPlayerToggle(@NotNull PlayerToggle toggle, @NotNull UUID uuid, boolean state) {
+  public static void notifyPlayerToggle(PlayerToggle toggle, UUID uuid, boolean state) {
     Bukkit.getPluginManager().callEvent(new PlayerToggledEvent(toggle, uuid, state));
   }
 

common/src/main/java/com/lishid/openinv/internal/Accessor.java

@@ -1,24 +0,0 @@
-package com.lishid.openinv.internal;
-
-import org.bukkit.configuration.ConfigurationSection;
-import org.bukkit.entity.Player;
-import org.bukkit.inventory.Inventory;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-
-public interface Accessor {
-
-  @NotNull
-  PlayerManager getPlayerManager();
-
-  @NotNull IAnySilentContainer getAnySilentContainer();
-
-  @NotNull ISpecialPlayerInventory createPlayerInventory(@NotNull Player player);
-
-  @NotNull ISpecialEnderChest createEnderChest(@NotNull Player player);
-
-  <T extends ISpecialInventory> @Nullable T get(@NotNull Inventory bukkitInventory, @NotNull Class<T> clazz);
-
-  void reload(@NotNull ConfigurationSection config);
-
-}

common/src/main/java/com/lishid/openinv/internal/AnySilentContainerBase.java

@@ -1,89 +0,0 @@
-package com.lishid.openinv.internal;
-
-import org.bukkit.block.Barrel;
-import org.bukkit.block.Block;
-import org.bukkit.block.BlockFace;
-import org.bukkit.block.BlockState;
-import org.bukkit.block.EnderChest;
-import org.bukkit.block.ShulkerBox;
-import org.bukkit.block.data.BlockData;
-import org.bukkit.block.data.type.Chest;
-import org.bukkit.inventory.Inventory;
-import org.bukkit.inventory.InventoryHolder;
-import org.jetbrains.annotations.NotNull;
-
-public abstract class AnySilentContainerBase implements IAnySilentContainer {
-
-  @Override
-  public boolean isAnyContainerNeeded(@NotNull Block block) {
-    BlockState blockState = getState(block);
-
-    // Barrels do not require AnyContainer.
-    if (blockState instanceof Barrel) {
-      return false;
-    }
-
-    // Enderchests require a non-occluding block on top to open.
-    if (blockState instanceof EnderChest) {
-      return block.getRelative(0, 1, 0).getType().isOccluding();
-    }
-
-    // Shulker boxes require half a block clear in the direction they open.
-    if (blockState instanceof ShulkerBox) {
-      return isShulkerBlocked(block);
-    }
-
-    if (!(blockState instanceof org.bukkit.block.Chest)) {
-      return false;
-    }
-
-    if (isChestBlocked(block)) {
-      return true;
-    }
-
-    BlockData blockData = block.getBlockData();
-    if (!(blockData instanceof Chest chest) || chest.getType() == Chest.Type.SINGLE) {
-      return false;
-    }
-
-    BlockFace relativeFace = switch (chest.getFacing()) {
-      case NORTH -> chest.getType() == Chest.Type.RIGHT ? BlockFace.WEST : BlockFace.EAST;
-      case EAST -> chest.getType() == Chest.Type.RIGHT ? BlockFace.NORTH : BlockFace.SOUTH;
-      case SOUTH -> chest.getType() == Chest.Type.RIGHT ? BlockFace.EAST : BlockFace.WEST;
-      case WEST -> chest.getType() == Chest.Type.RIGHT ? BlockFace.SOUTH : BlockFace.NORTH;
-      default -> BlockFace.SELF;
-    };
-    Block relative = block.getRelative(relativeFace);
-
-    if (relative.getType() != block.getType()) {
-      return false;
-    }
-
-    BlockData relativeData = relative.getBlockData();
-    if (!(relativeData instanceof Chest relativeChest)) {
-      return false;
-    }
-
-    if (relativeChest.getFacing() != chest.getFacing()
-        || relativeChest.getType() != (chest.getType() == Chest.Type.RIGHT ? Chest.Type.LEFT : Chest.Type.RIGHT)) {
-      return false;
-    }
-
-    return isChestBlocked(relative);
-  }
-
-  @Override
-  public boolean isAnySilentContainer(@NotNull Block block) {
-    return isAnySilentContainer(getState(block));
-  }
-
-  @Override
-  public boolean isAnySilentContainer(@NotNull Inventory inventory) {
-    return isAnySilentContainer(getHolder(inventory));
-  }
-
-  protected abstract BlockState getState(@NotNull Block block);
-
-  protected abstract InventoryHolder getHolder(@NotNull Inventory inventory);
-
-}

common/src/main/java/com/lishid/openinv/internal/InternalOwned.java

@@ -1,7 +0,0 @@
-package com.lishid.openinv.internal;
-
-public interface InternalOwned<T> {
-
-  T getOwnerHandle();
-
-}

common/src/main/java/com/lishid/openinv/internal/ViewOnly.java

@@ -1,4 +0,0 @@
-package com.lishid.openinv.internal;
-
-public interface ViewOnly {
-}

common/src/main/java/com/lishid/openinv/util/lang/Replacement.java

@@ -1,29 +0,0 @@
-/*
- * Copyright (C) 2011-2022 lishid. All rights reserved.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 3.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-package com.lishid.openinv.util.lang;
-
-import org.jetbrains.annotations.NotNull;
-
-/**
- * A data holder for string replacement in translations.
- *
- * @param placeholder the placeholder to be replaced
- * @param value the value to insert
- */
-public record Replacement(@NotNull String placeholder, @NotNull String value) {
-
-}

gradle.properties

@@ -1,6 +1,6 @@
 # Project meta
 group=com.lishid.openinv
-version=5.3.3
+version=5.3.5
 description=A Bukkit plugin for opening normally-inaccessible inventories.
 
 # Gradle configuration

gradle/libs.versions.toml

@@ -1,15 +1,18 @@
 [versions]
-spigotapi = "1.21.5-R0.1-SNAPSHOT"
+spigotapi = "1.21.3-R0.1-SNAPSHOT"
 planarwrappers = "3.3.0"
-jspecify = "1.0.0"
+jspecify = "1.0.1"
 annotations = "26.1.0"
 paperweight = "2.0.0-beta.21"
-shadow = "9.4.2"
+shadow = "9.6.1"
 folia-scheduler-wrapper = "v0.0.3"
-errorprone-core = "2.49.0"
-errorprone-gradle = "5.1.0"
-slf4j = "2.0.18"
+errorprone-core = "2.50.0"
+errorprone-gradle = "5.1.1"
+slf4j = "2.0.20"
 sqlite-jdbc = "3.49.1.0"
+mockito-core = "5.24.0"
+junit-jupiter = "6.1.3"
+hamcrest = "3.0"
 
 [libraries]
 spigotapi = { module = "org.spigotmc:spigot-api", version.ref = "spigotapi" }
@@ -20,6 +23,9 @@ folia-scheduler-wrapper = { module = "com.github.NahuLD.folia-scheduler-wrapper:
 errorprone-core = { module = "com.google.errorprone:error_prone_core", version.ref = "errorprone-core" }
 slf4j-api = { module = "org.slf4j:slf4j-api", version.ref = "slf4j" }
 sqlite-jdbc = { module = "org.xerial:sqlite-jdbc", version.ref = "sqlite-jdbc" }
+mockito-core = { module = "org.mockito:mockito-core", version.ref = "mockito-core" }
+junit-jupiter = { module = "org.junit.jupiter:junit-jupiter", version.ref = "junit-jupiter" }
+hamcrest = { module = "org.hamcrest:hamcrest", version.ref = "hamcrest" }
 
 [plugins]
 paperweight = { id = "io.papermc.paperweight.userdev", version.ref = "paperweight" }

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.5.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.8.0-bin.zip
 networkTimeout=10000
 retries=0
 retryBackOffMs=500

gradlew

@@ -20,7 +20,7 @@
 
 ##############################################################################
 #
-#   Gradle start up script for POSIX generated by Gradle.
+#   gradlew start up script for POSIX generated by Gradle.
 #
 #   Important for running:
 #
@@ -29,7 +29,7 @@
 #       bash, then to run this script, type that shell name before the whole
 #       command line, like:
 #
-#           ksh Gradle
+#           ksh gradlew
 #
 #       Busybox and similar reduced shells will NOT work, because this script
 #       requires all of these POSIX shell features:

gradlew.bat

@@ -19,13 +19,40 @@
 @if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
-@rem  Gradle startup script for Windows
+@rem  gradlew startup script for Windows
 @rem
 @rem ##########################################################################
 
 @rem Set local scope for the variables, and ensure extensions are enabled
 setlocal EnableExtensions
 
+@rem Catch executions from older scripts and ensure they exit cleanly.
+@rem This can be removed once we can be reasonably confident that few people
+@rem will be migrating directly to this new wrapper.
+goto afterSafetyNet
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+goto exitWithErrorLevel
+:afterSafetyNet
+
 set DIRNAME=%~dp0
 if "%DIRNAME%"=="" set DIRNAME=.
 @rem This is normally unused
@@ -45,13 +72,14 @@ set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
 if %ERRORLEVEL% equ 0 goto execute
 
-echo. 1>&2
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
-echo. 1>&2
-echo Please set the JAVA_HOME variable in your environment to match the 1>&2
-echo location of your Java installation. 1>&2
+1>&2 echo.
+1>&2 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+1>&2 echo.
+1>&2 echo Please set the JAVA_HOME variable in your environment to match the
+1>&2 echo location of your Java installation.
 
 "%COMSPEC%" /c exit 1
+goto exitWithErrorLevel
 
 :findJavaFromJavaHome
 set JAVA_HOME=%JAVA_HOME:"=%
@@ -59,24 +87,26 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo. 1>&2
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
-echo. 1>&2
-echo Please set the JAVA_HOME variable in your environment to match the 1>&2
-echo location of your Java installation. 1>&2
+1>&2 echo.
+1>&2 echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+1>&2 echo.
+1>&2 echo Please set the JAVA_HOME variable in your environment to match the
+1>&2 echo location of your Java installation.
 
 "%COMSPEC%" /c exit 1
+goto exitWithErrorLevel
 
 :execute
 @rem Setup the command line
 
 
 
-@rem Execute Gradle
+@rem Execute gradlew
 @rem endlocal doesn't take effect until after the line is parsed and variables are expanded
 @rem which allows us to clear the local environment before executing the java command
-endlocal & "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %* & call :exitWithErrorLevel
+endlocal & "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %* & call :exitWithErrorLevel & goto exitWithErrorLevel
 
+@rem This label must not be changed. We rely on old scripts being able to jump to this point.
 :exitWithErrorLevel
 @rem Use "%COMSPEC%" /c exit to allow operators to work properly in scripts
 "%COMSPEC%" /c exit %ERRORLEVEL%

internal/paper1_21_10/build.gradle.kts

@@ -1,28 +0,0 @@
-plugins {
-  alias(libs.plugins.paperweight)
-}
-
-java {
-  toolchain.languageVersion = JavaLanguageVersion.of(21)
-}
-
-tasks.withType<JavaCompile>().configureEach {
-  options.release = 21
-}
-
-dependencies {
-  implementation(project(":openinvapi")) {
-    exclude(group = "org.spigotmc", module = "spigot-api")
-  }
-  implementation(project(":openinvcommon")) {
-    exclude(group = "org.spigotmc", module = "spigot-api")
-  }
-  implementation(project(":openinvadapterpaper26_1")) {
-    exclude(group = "io.papermc.paper", module = "dev-bundle")
-  }
-  implementation(project(":openinvadapterpaper1_21_11")) {
-    exclude(group = "io.papermc.paper", module = "dev-bundle")
-  }
-
-  paperweight.paperDevBundle("1.21.10-R0.1-SNAPSHOT")
-}

internal/paper1_21_10/src/main/java/com/lishid/openinv/internal/paper1_21_10/InternalAccessor.java

@@ -1,31 +0,0 @@
-package com.lishid.openinv.internal.paper1_21_10;
-
-import com.lishid.openinv.internal.ISpecialPlayerInventory;
-import com.lishid.openinv.internal.paper1_21_10.container.OpenInventory;
-import com.lishid.openinv.internal.paper1_21_10.player.PlayerManager;
-import com.lishid.openinv.util.lang.LanguageManager;
-import org.bukkit.entity.Player;
-import org.jetbrains.annotations.NotNull;
-
-import java.util.logging.Logger;
-
-public class InternalAccessor extends com.lishid.openinv.internal.paper1_21_11.InternalAccessor {
-
-  private final @NotNull PlayerManager manager;
-
-  public InternalAccessor(@NotNull Logger logger, @NotNull LanguageManager lang) {
-    super(logger, lang);
-    manager = new PlayerManager(logger);
-  }
-
-  @Override
-  public @NotNull PlayerManager getPlayerManager() {
-    return manager;
-  }
-
-  @Override
-  public @NotNull ISpecialPlayerInventory createPlayerInventory(@NotNull Player player) {
-    return new OpenInventory(player);
-  }
-
-}

internal/paper1_21_10/src/main/java/com/lishid/openinv/internal/paper1_21_10/container/OpenInventory.java

@@ -1,59 +0,0 @@
-package com.lishid.openinv.internal.paper1_21_10.container;
-
-import com.lishid.openinv.internal.paper1_21_11.container.menu.OpenInventoryMenu;
-import com.lishid.openinv.internal.paper26_2.container.BaseOpenInventory;
-import com.lishid.openinv.internal.paper26_2.container.menu.OpenChestMenu;
-import net.minecraft.ChatFormatting;
-import net.minecraft.network.chat.Component;
-import net.minecraft.network.chat.FontDescription;
-import net.minecraft.network.chat.MutableComponent;
-import net.minecraft.resources.ResourceLocation;
-import net.minecraft.server.level.ServerPlayer;
-import org.bukkit.entity.Player;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-
-public class OpenInventory extends BaseOpenInventory {
-
-  public OpenInventory(@NotNull Player bukkitPlayer) {
-    super(bukkitPlayer);
-  }
-
-  @Override
-  public @NotNull Component getTitle(@Nullable ServerPlayer viewer, @Nullable OpenChestMenu<?> menu) {
-    MutableComponent component = Component.empty();
-    // Prefix for use with custom bitmap image fonts.
-    if (owner.equals(viewer)) {
-      component.append(
-          Component.translatableWithFallback("openinv.container.inventory.self", "")
-              .withStyle(style -> style
-                  .withFont(new FontDescription.Resource(ResourceLocation.parse("openinv:font/inventory")))
-                  .withColor(ChatFormatting.WHITE)));
-    } else {
-      component.append(
-          Component.translatableWithFallback("openinv.container.inventory.other", "")
-              .withStyle(style -> style
-                  .withFont(new FontDescription.Resource(ResourceLocation.parse("openinv:font/inventory")))
-                  .withColor(ChatFormatting.WHITE)));
-    }
-    if (menu != null && menu.isViewOnly()) {
-      component.append(Component.translatableWithFallback("openinv.container.inventory.viewonly", "[RO] "));
-    } else {
-      component.append(Component.translatableWithFallback("openinv.container.inventory.editable", ""));
-    }
-    // Normal title: "Inventory - OwnerName"
-    component.append(Component.translatableWithFallback("openinv.container.inventory.prefix", "", owner.getName()))
-        .append(Component.translatable("container.inventory"))
-        .append(Component.translatableWithFallback("openinv.container.inventory.suffix", " - %s", owner.getName()));
-    return component;
-  }
-
-  @Override
-  public @Nullable OpenChestMenu<?> createMenu(net.minecraft.world.entity.player.Player player, int i, boolean viewOnly) {
-    if (player instanceof ServerPlayer serverPlayer) {
-      return new OpenInventoryMenu(this, serverPlayer, i, viewOnly);
-    }
-    return null;
-  }
-
-}

internal/paper1_21_10/src/main/java/com/lishid/openinv/internal/paper1_21_10/player/OpenPlayer.java

@@ -1,35 +0,0 @@
-package com.lishid.openinv.internal.paper1_21_10.player;
-
-import com.lishid.openinv.internal.paper26_1.player.PlayerManager;
-import net.minecraft.nbt.CompoundTag;
-import net.minecraft.server.level.ServerPlayer;
-import org.bukkit.craftbukkit.CraftServer;
-import org.jetbrains.annotations.NotNull;
-
-import java.nio.file.Path;
-
-public class OpenPlayer extends com.lishid.openinv.internal.paper26_2.player.OpenPlayer {
-
-  protected OpenPlayer(
-      CraftServer server,
-      ServerPlayer entity,
-      PlayerManager manager
-  ) {
-    super(server, entity, manager);
-  }
-
-  @Override
-  protected void safeReplaceFile(
-      @NotNull Path dataFile,
-      @NotNull Path tempFile,
-      @NotNull Path backupFile
-  ) {
-    net.minecraft.Util.safeReplaceFile(dataFile, tempFile, backupFile);
-  }
-
-  @Override
-  protected void remove(@NotNull CompoundTag tag, @NotNull String key) {
-    tag.remove(key);
-  }
-
-}

internal/paper1_21_10/src/main/java/com/lishid/openinv/internal/paper1_21_10/player/PlayerManager.java

@@ -1,26 +0,0 @@
-package com.lishid.openinv.internal.paper1_21_10.player;
-
-import net.minecraft.server.MinecraftServer;
-import net.minecraft.server.level.ServerPlayer;
-import org.jetbrains.annotations.NotNull;
-
-import java.util.logging.Logger;
-
-public class PlayerManager extends com.lishid.openinv.internal.paper26_1.player.PlayerManager {
-
-  public PlayerManager(@NotNull Logger logger) {
-    super(logger);
-  }
-
-  @Override
-  protected void injectPlayer(@NotNull MinecraftServer server, @NotNull ServerPlayer player) throws IllegalAccessException {
-    if (bukkitEntity == null) {
-      return;
-    }
-
-    bukkitEntity.setAccessible(true);
-
-    bukkitEntity.set(player, new OpenPlayer(server.server, player, this));
-  }
-
-}

internal/paper1_21_11/src/main/java/com/lishid/openinv/internal/paper1_21_11/InternalAccessor.java

@@ -1,29 +1,30 @@
 package com.lishid.openinv.internal.paper1_21_11;
 
+import com.github.jikoo.openinv.lang.LanguageManager;
 import com.lishid.openinv.internal.ISpecialEnderChest;
 import com.lishid.openinv.internal.ISpecialPlayerInventory;
 import com.lishid.openinv.internal.paper1_21_11.container.OpenEnderChest;
 import com.lishid.openinv.internal.paper1_21_11.container.OpenInventory;
-import com.lishid.openinv.util.lang.LanguageManager;
 import org.bukkit.entity.Player;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.logging.Logger;
 
+@NullMarked
 public class InternalAccessor extends com.lishid.openinv.internal.paper26_1.InternalAccessor {
 
-  public InternalAccessor(@NotNull Logger logger, @NotNull LanguageManager lang) {
+  public InternalAccessor(Logger logger, LanguageManager lang) {
     super(logger, lang);
   }
 
   @Override
-  public @NotNull ISpecialEnderChest createEnderChest(@NotNull Player player) {
+  public ISpecialEnderChest createEnderChest(Player player) {
     return new OpenEnderChest(player);
   }
 
   @Override
-  public @NotNull ISpecialPlayerInventory createPlayerInventory(@NotNull Player player) {
-    return new OpenInventory(player);
+  public ISpecialPlayerInventory createPlayerInventory(Player player) {
+    return new OpenInventory(factory, player);
   }
 
 }

internal/paper1_21_11/src/main/java/com/lishid/openinv/internal/paper1_21_11/container/OpenEnderChest.java

@@ -1,23 +1,33 @@
 package com.lishid.openinv.internal.paper1_21_11.container;
 
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
 import com.lishid.openinv.internal.paper1_21_11.container.menu.OpenEnderChestMenu;
-import com.lishid.openinv.internal.paper26_2.container.menu.OpenChestMenu;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
 import org.jetbrains.annotations.Nullable;
 import org.jspecify.annotations.NullMarked;
 
 @NullMarked
-public class OpenEnderChest extends com.lishid.openinv.internal.paper26_2.container.OpenEnderChest {
+public class OpenEnderChest extends com.lishid.openinv.internal.paper26_3.container.OpenEnderChest {
 
   public OpenEnderChest(org.bukkit.entity.Player player) {
     super(player);
   }
 
   @Override
-  public @Nullable OpenChestMenu<?> createMenu(Player player, int i, boolean viewOnly) {
+  public @Nullable OpenChestMenu<?> createMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      Player player,
+      int i,
+      boolean viewOnly
+  ) {
     if (player instanceof ServerPlayer serverPlayer) {
-      return new OpenEnderChestMenu(this, serverPlayer, i, viewOnly);
+      return new OpenEnderChestMenu(factory, this, serverPlayer, i, viewOnly);
     }
     return null;
   }

internal/paper1_21_11/src/main/java/com/lishid/openinv/internal/paper1_21_11/container/OpenInventory.java

@@ -1,23 +1,31 @@
 package com.lishid.openinv.internal.paper1_21_11.container;
 
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
 import com.lishid.openinv.internal.paper1_21_11.container.menu.OpenInventoryMenu;
-import com.lishid.openinv.internal.paper26_2.container.menu.OpenChestMenu;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
 import org.jetbrains.annotations.Nullable;
 import org.jspecify.annotations.NullMarked;
 
 @NullMarked
-public class OpenInventory extends com.lishid.openinv.internal.paper26_2.container.OpenInventory {
+public class OpenInventory extends com.lishid.openinv.internal.paper26_3.container.OpenInventory {
 
-  public OpenInventory(org.bukkit.entity.Player bukkitPlayer) {
-    super(bukkitPlayer);
+  public OpenInventory(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      org.bukkit.entity.Player bukkitPlayer
+  ) {
+    super(factory, bukkitPlayer);
   }
 
   @Override
   public @Nullable OpenChestMenu<?> createMenu(Player player, int i, boolean viewOnly) {
     if (player instanceof ServerPlayer serverPlayer) {
-      return new OpenInventoryMenu(this, serverPlayer, i, viewOnly);
+      return new OpenInventoryMenu(factory, this, serverPlayer, i, viewOnly);
     }
     return null;
   }

internal/paper1_21_11/src/main/java/com/lishid/openinv/internal/paper1_21_11/container/menu/OpenEnderChestMenu.java

@@ -1,8 +1,11 @@
 package com.lishid.openinv.internal.paper1_21_11.container.menu;
 
-import com.lishid.openinv.internal.paper26_2.container.OpenEnderChest;
-import com.lishid.openinv.internal.paper26_2.container.menu.OpenSyncMenu;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.OpenEnderChest;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenSyncMenu;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.inventory.ClickType;
 import net.minecraft.world.inventory.Slot;
@@ -13,12 +16,13 @@ import org.jspecify.annotations.NullMarked;
 public class OpenEnderChestMenu extends OpenSyncMenu<OpenEnderChest> {
 
   public OpenEnderChestMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
       OpenEnderChest enderChest,
       ServerPlayer viewer,
       int containerId,
       boolean viewOnly
   ) {
-    super(getChestMenuType(enderChest.getContainerSize()), containerId, enderChest, viewer, viewOnly);
+    super(getChestMenuType(enderChest.getContainerSize()), containerId, factory, enderChest, viewer, viewOnly);
   }
 
   @Override

internal/paper1_21_11/src/main/java/com/lishid/openinv/internal/paper1_21_11/container/menu/OpenInventoryMenu.java

@@ -1,17 +1,28 @@
 package com.lishid.openinv.internal.paper1_21_11.container.menu;
 
-import com.lishid.openinv.internal.paper26_2.container.BaseOpenInventory;
-import com.lishid.openinv.internal.paper26_2.container.menu.BaseOpenInventoryMenu;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.BaseOpenInventory;
+import com.lishid.openinv.internal.paper26_3.container.menu.BaseOpenInventoryMenu;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.inventory.ClickType;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
 import org.jspecify.annotations.NullMarked;
 
 @NullMarked
 public class OpenInventoryMenu extends BaseOpenInventoryMenu {
 
-  public OpenInventoryMenu(BaseOpenInventory inventory, ServerPlayer viewer, int i, boolean viewOnly) {
-    super(inventory, viewer, i, viewOnly);
+  public OpenInventoryMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      BaseOpenInventory inventory,
+      ServerPlayer viewer,
+      int i,
+      boolean viewOnly
+  ) {
+    super(factory, inventory, viewer, i, viewOnly);
   }
 
   @Override

internal/paper26_1/build.gradle.kts

@@ -1,5 +1,3 @@
-import org.gradle.api.internal.attributes.DefaultCompatibilityRuleChain
-
 plugins {
   alias(libs.plugins.paperweight)
 }
@@ -8,49 +6,25 @@ repositories {
   maven("https://repo.papermc.io/repository/maven-public/")
 }
 
+// Paper is compiled with Java 25, so we have to use a Java 25 toolchain.
 java {
   toolchain.languageVersion.set(JavaLanguageVersion.of(25))
 }
 
+// To minimize duplicate code, the adapter for 1.21.11 is built off of this module, so we need to target Java 21.
 tasks.withType<JavaCompile>().configureEach {
   options.release = 21
 }
 
-class ToolchainJvmVersion: AttributeCompatibilityRule<Int> {
-  override fun execute(details: CompatibilityCheckDetails<Int>) {
-    if (details.consumerValue == details.producerValue) {
-      details.compatible()
-      return
-    }
-    if (details.producerValue == null) {
-      details.incompatible()
-      return
-    }
-    if (25 >= details.producerValue!!) {
-      details.compatible()
-    } else {
-      details.incompatible()
-    }
+// As a result, we have to specifically tell Gradle it's okay if our dependencies require Java 25,
+// because secretly sometimes they don't!
+configurations.matching { it.isCanBeResolved && it.name.endsWith("Classpath") }.all {
+  attributes {
+    attribute(TargetJvmVersion.TARGET_JVM_VERSION_ATTRIBUTE, 25)
   }
 }
 
 dependencies {
-  attributesSchema {
-    attribute(TargetJvmVersion.TARGET_JVM_VERSION_ATTRIBUTE) {
-      // Gradle thinks that depending on a library with a certain language level requires
-      // any project that depends on it to also require that language level no matter what.
-      // This is a bit obnoxious when we're specifically adding compatiblity patches to shared common code.
-      // Realistically Gradle is correct and the chain should be reversed - the oldest, least common
-      // denominator should be targeted and patches should be slapped on top as necessary.
-      // However, I don't want to spend a week restructuring the project to cut a release.
-      // Hack out Gradle's rules and replace them with our own less-restrictive version.
-      val rules = compatibilityRules as DefaultCompatibilityRuleChain
-      rules.rules.clear()
-
-      compatibilityRules.add(ToolchainJvmVersion::class.java)
-    }
-  }
-
   implementation(project(":openinvapi")) {
     exclude(group = "org.spigotmc", module = "spigot-api")
   }
@@ -61,7 +35,7 @@ dependencies {
     exclude(group = "io.papermc.paper", module = "dev-bundle")
   }
 
-  paperweight.paperDevBundle("26.1.2.build.5-alpha")
+  paperweight.paperDevBundle("26.1.2.build.+")
 }
 
 tasks.reobfJar {

internal/paper26_1/src/main/java/com/lishid/openinv/internal/paper26_1/InternalAccessor.java

@@ -1,42 +1,52 @@
 package com.lishid.openinv.internal.paper26_1;
 
 import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
 import com.lishid.openinv.internal.paper26_1.container.AnySilentContainer;
 import com.lishid.openinv.internal.paper26_1.container.OpenEnderChest;
 import com.lishid.openinv.internal.paper26_1.player.PlayerManager;
-import com.lishid.openinv.internal.paper26_2.container.slot.placeholder.PlaceholderLoader;
-import com.lishid.openinv.util.lang.LanguageManager;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.PlaceholderLoader;
+import com.github.jikoo.openinv.lang.LanguageManager;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
 import org.bukkit.entity.Player;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.logging.Logger;
 
+@NullMarked
 public class InternalAccessor extends com.lishid.openinv.internal.paper26_2.InternalAccessor {
 
-  public InternalAccessor(@NotNull Logger logger, @NotNull LanguageManager lang) {
+  public InternalAccessor(Logger logger, LanguageManager lang) {
     super(logger, lang);
   }
 
   @Override
-  protected @NotNull PlayerManager createPlayerManager(@NotNull Logger logger) {
-    return new PlayerManager(logger);
+  protected PlayerManager createPlayerManager(
+      Logger logger,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory
+  ) {
+    return new PlayerManager(logger, factory);
   }
 
   @Override
-  protected @NotNull AnySilentContainer createAnySilentContainer(
-      @NotNull Logger logger,
-      @NotNull LanguageManager lang
+  protected AnySilentContainer createAnySilentContainer(
+      Logger logger,
+      LanguageManager lang
   ) {
     return new AnySilentContainer(logger, lang);
   }
 
   @Override
-  protected @NotNull PlaceholderLoader createPlaceholderLoader() {
+  protected PlaceholderLoader createPlaceholderLoader() {
     return new com.lishid.openinv.internal.paper26_1.container.slot.placeholder.PlaceholderLoader();
   }
 
   @Override
-  public @NotNull ISpecialEnderChest createEnderChest(@NotNull Player player) {
+  public ISpecialEnderChest createEnderChest(Player player) {
     return new OpenEnderChest(player);
   }
 

internal/paper26_1/src/main/java/com/lishid/openinv/internal/paper26_1/container/AnySilentContainer.java

@@ -1,19 +1,20 @@
 package com.lishid.openinv.internal.paper26_1.container;
 
-import com.lishid.openinv.util.lang.LanguageManager;
+import com.github.jikoo.openinv.lang.LanguageManager;
 import net.minecraft.world.level.block.entity.RandomizableContainerBlockEntity;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.logging.Logger;
 
-public class AnySilentContainer extends com.lishid.openinv.internal.paper26_2.container.AnySilentContainer {
+@NullMarked
+public class AnySilentContainer extends com.lishid.openinv.internal.paper26_3.container.AnySilentContainer {
 
-  public AnySilentContainer(@NotNull Logger logger, @NotNull LanguageManager lang) {
+  public AnySilentContainer(Logger logger, LanguageManager lang) {
     super(logger, lang);
   }
 
   @Override
-  protected boolean hasLootTable(@NotNull RandomizableContainerBlockEntity lootable) {
+  protected boolean hasLootTable(RandomizableContainerBlockEntity lootable) {
     return lootable.lootTable != null;
   }
 

internal/paper26_1/src/main/java/com/lishid/openinv/internal/paper26_1/container/OpenEnderChest.java

@@ -3,16 +3,17 @@ package com.lishid.openinv.internal.paper26_1.container;
 import net.minecraft.core.NonNullList;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.item.ItemStack;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
-public class OpenEnderChest extends com.lishid.openinv.internal.paper26_2.container.OpenEnderChest {
+@NullMarked
+public class OpenEnderChest extends com.lishid.openinv.internal.paper26_3.container.OpenEnderChest {
 
-  public OpenEnderChest(@NotNull org.bukkit.entity.Player player) {
+  public OpenEnderChest(org.bukkit.entity.Player player) {
     super(player);
   }
 
   @Override
-  protected @NotNull NonNullList<ItemStack> getEnderChestItems(@NotNull ServerPlayer owner) {
+  protected NonNullList<ItemStack> getEnderChestItems(ServerPlayer owner) {
     return owner.getEnderChestInventory().items;
   }
 

internal/paper26_1/src/main/java/com/lishid/openinv/internal/paper26_1/container/slot/placeholder/PlaceholderLoader.java

@@ -2,17 +2,18 @@ package com.lishid.openinv.internal.paper26_1.container.slot.placeholder;
 
 import net.minecraft.world.item.Item;
 import net.minecraft.world.item.Items;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
-public class PlaceholderLoader extends com.lishid.openinv.internal.paper26_2.container.slot.placeholder.PlaceholderLoader {
+@NullMarked
+public class PlaceholderLoader extends com.lishid.openinv.internal.paper26_3.container.slot.placeholder.PlaceholderLoader {
 
   @Override
-  protected @NotNull Item getDefaultCursorItem() {
+  protected Item getDefaultCursorItem() {
     return Items.WHITE_BANNER;
   }
 
   @Override
-  protected @NotNull Item getDefaultNotSlotItem() {
+  protected Item getDefaultNotSlotItem() {
     return Items.WHITE_STAINED_GLASS_PANE;
   }
 

internal/paper26_1/src/main/java/com/lishid/openinv/internal/paper26_1/player/PlayerManager.java

@@ -1,7 +1,12 @@
 package com.lishid.openinv.internal.paper26_1.player;
 
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.storage.LevelData;
 import net.minecraft.world.phys.Vec3;
 import org.jspecify.annotations.NullMarked;
@@ -9,10 +14,13 @@ import org.jspecify.annotations.NullMarked;
 import java.util.logging.Logger;
 
 @NullMarked
-public class PlayerManager extends com.lishid.openinv.internal.paper26_2.player.PlayerManager {
+public class PlayerManager extends com.lishid.openinv.internal.paper26_3.player.PlayerManager {
 
-  public PlayerManager(Logger logger) {
-    super(logger);
+  public PlayerManager(
+      Logger logger,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory
+  ) {
+    super(logger, factory);
   }
 
   @Override

internal/paper26_2/build.gradle.kts

@@ -1,5 +1,3 @@
-import org.gradle.api.internal.attributes.DefaultCompatibilityRuleChain
-
 plugins {
   alias(libs.plugins.paperweight)
 }
@@ -8,57 +6,36 @@ repositories {
   maven("https://repo.papermc.io/repository/maven-public/")
 }
 
+// Paper is compiled with Java 25, so we have to use a Java 25 toolchain.
 java {
   toolchain.languageVersion.set(JavaLanguageVersion.of(25))
 }
 
+// To minimize duplicate code, the adapter for 1.21.11 is built off of this module, so we need to target Java 21.
 tasks.withType<JavaCompile>().configureEach {
   options.release = 21
 }
 
-class ToolchainJvmVersion: AttributeCompatibilityRule<Int> {
-  override fun execute(details: CompatibilityCheckDetails<Int>) {
-    if (details.consumerValue == details.producerValue) {
-      details.compatible()
-      return
-    }
-    if (details.producerValue == null) {
-      details.incompatible()
-      return
-    }
-    if (25 >= details.producerValue!!) {
-      details.compatible()
-    } else {
-      details.incompatible()
-    }
+// As a result, we have to specifically tell Gradle it's okay if our dependencies require Java 25,
+// because secretly sometimes they don't!
+configurations.matching { it.isCanBeResolved && it.name.endsWith("Classpath") }.all {
+  attributes {
+    attribute(TargetJvmVersion.TARGET_JVM_VERSION_ATTRIBUTE, 25)
   }
 }
 
 dependencies {
-  attributesSchema {
-    attribute(TargetJvmVersion.TARGET_JVM_VERSION_ATTRIBUTE) {
-      // Gradle thinks that depending on a library with a certain language level requires
-      // any project that depends on it to also require that language level no matter what.
-      // This is a bit obnoxious when we're specifically adding compatiblity patches to shared common code.
-      // Realistically Gradle is correct and the chain should be reversed - the oldest, least common
-      // denominator should be targeted and patches should be slapped on top as necessary.
-      // However, I don't want to spend a week restructuring the project to cut a release.
-      // Hack out Gradle's rules and replace them with our own less-restrictive version.
-      val rules = compatibilityRules as DefaultCompatibilityRuleChain
-      rules.rules.clear()
-
-      compatibilityRules.add(ToolchainJvmVersion::class.java)
-    }
-  }
-
   implementation(project(":openinvapi")) {
     exclude(group = "org.spigotmc", module = "spigot-api")
   }
   implementation(project(":openinvcommon")) {
     exclude(group = "org.spigotmc", module = "spigot-api")
   }
+  api(project(":openinvadapterpaper26_3")) {
+    exclude(group = "io.papermc.paper", module = "dev-bundle")
+  }
 
-  paperweight.paperDevBundle("26.2.build.31-alpha")
+  paperweight.paperDevBundle("26.2.build.+")
 }
 
 tasks.reobfJar {

internal/paper26_2/src/main/java/com/lishid/openinv/internal/paper26_2/InternalAccessor.java

@@ -1,95 +1,27 @@
 package com.lishid.openinv.internal.paper26_2;
 
-import com.lishid.openinv.internal.Accessor;
-import com.lishid.openinv.internal.IAnySilentContainer;
-import com.lishid.openinv.internal.ISpecialEnderChest;
-import com.lishid.openinv.internal.ISpecialInventory;
-import com.lishid.openinv.internal.ISpecialPlayerInventory;
-import com.lishid.openinv.internal.paper26_2.container.AnySilentContainer;
-import com.lishid.openinv.internal.paper26_2.container.OpenEnderChest;
-import com.lishid.openinv.internal.paper26_2.container.OpenInventory;
-import com.lishid.openinv.internal.paper26_2.container.slot.placeholder.PlaceholderLoader;
-import com.lishid.openinv.internal.paper26_2.player.PlayerManager;
-import com.lishid.openinv.util.lang.LanguageManager;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_2.container.slot.OpenInventoryFactory;
+import com.github.jikoo.openinv.lang.LanguageManager;
+import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.Container;
-import org.bukkit.configuration.ConfigurationSection;
-import org.bukkit.craftbukkit.inventory.CraftInventory;
-import org.bukkit.entity.Player;
-import org.bukkit.inventory.Inventory;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
 
-import java.util.logging.Level;
 import java.util.logging.Logger;
 
-public class InternalAccessor implements Accessor {
+@NullMarked
+public class InternalAccessor extends com.lishid.openinv.internal.paper26_3.InternalAccessor {
 
-  protected final @NotNull Logger logger;
-  private final @NotNull PlayerManager manager;
-  private final @NotNull AnySilentContainer anySilentContainer;
-
-  public InternalAccessor(@NotNull Logger logger, @NotNull LanguageManager lang) {
-    this.logger = logger;
-    manager = createPlayerManager(logger);
-    anySilentContainer = createAnySilentContainer(logger, lang);
-  }
-
-  protected @NotNull PlayerManager createPlayerManager(@NotNull Logger logger) {
-    return new PlayerManager(logger);
-  }
-
-  protected @NotNull AnySilentContainer createAnySilentContainer(
-      @NotNull Logger logger,
-      @NotNull LanguageManager lang
-  ) {
-    return new AnySilentContainer(logger, lang);
-  }
-
-  protected @NotNull PlaceholderLoader createPlaceholderLoader() {
-    return new PlaceholderLoader();
+  public InternalAccessor(Logger logger, LanguageManager lang) {
+    super(logger, lang);
   }
 
   @Override
-  public @NotNull PlayerManager getPlayerManager() {
-    return manager;
-  }
-
-  @Override
-  public @NotNull IAnySilentContainer getAnySilentContainer() {
-    return anySilentContainer;
-  }
-
-  @Override
-  public @NotNull ISpecialPlayerInventory createPlayerInventory(@NotNull Player player) {
-    return new OpenInventory(player);
-  }
-
-  @Override
-  public @NotNull ISpecialEnderChest createEnderChest(@NotNull Player player) {
-    return new OpenEnderChest(player);
-  }
-
-  @Override
-  public <T extends ISpecialInventory> @Nullable T get(@NotNull Inventory bukkitInventory, @NotNull Class<T> clazz) {
-    if (!(bukkitInventory instanceof CraftInventory craftInventory)) {
-      return null;
-    }
-    Container container = craftInventory.getInventory();
-    if (clazz.isInstance(container)) {
-      return clazz.cast(container);
-    }
-    return null;
-  }
-
-  @Override
-  public void reload(@NotNull ConfigurationSection config) {
-    ConfigurationSection placeholders = config.getConfigurationSection("placeholders");
-    try {
-      // Reset placeholders to defaults and try to load configuration.
-      createPlaceholderLoader().load(placeholders);
-    } catch (Exception e) {
-      logger.log(Level.WARNING, "Caught exception loading placeholder overrides!", e);
-    }
+  protected InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> createInventoryFactory() {
+    return new OpenInventoryFactory();
   }
 
 }

internal/paper26_2/src/main/java/com/lishid/openinv/internal/paper26_2/container/bukkit/OpenPlayerInventorySelf.java

@@ -1,26 +0,0 @@
-package com.lishid.openinv.internal.paper26_2.container.bukkit;
-
-import com.lishid.openinv.internal.paper26_2.container.BaseOpenInventory;
-import org.bukkit.inventory.ItemStack;
-import org.jetbrains.annotations.NotNull;
-
-public class OpenPlayerInventorySelf extends OpenPlayerInventory {
-
-  private final int offset;
-
-  public OpenPlayerInventorySelf(@NotNull BaseOpenInventory inventory, int offset) {
-    super(inventory);
-    this.offset = offset;
-  }
-
-  @Override
-  public ItemStack getItem(int index) {
-    return super.getItem(offset + index);
-  }
-
-  @Override
-  public void setItem(int index, ItemStack item) {
-    super.setItem(offset + index, item);
-  }
-
-}

internal/paper26_2/src/main/java/com/lishid/openinv/internal/paper26_2/container/menu/OpenInventoryMenu.java

@@ -1,26 +0,0 @@
-package com.lishid.openinv.internal.paper26_2.container.menu;
-
-import com.lishid.openinv.internal.paper26_2.container.BaseOpenInventory;
-import net.minecraft.server.level.ServerPlayer;
-import net.minecraft.world.entity.player.Player;
-import net.minecraft.world.inventory.ContainerInput;
-import org.jspecify.annotations.NullMarked;
-
-@NullMarked
-public class OpenInventoryMenu extends BaseOpenInventoryMenu {
-
-  public OpenInventoryMenu(BaseOpenInventory inventory, ServerPlayer viewer, int i, boolean viewOnly) {
-    super(inventory, viewer, i, viewOnly);
-  }
-
-  @Override
-  public void clicked(int slotIndex, int buttonNum, ContainerInput containerInput, Player player) {
-    if (viewOnly) {
-      if (containerInput == ContainerInput.QUICK_CRAFT) {
-        sendAllDataToRemote();
-      }
-    }
-    super.clicked(slotIndex, buttonNum, containerInput, player);
-  }
-
-}

internal/paper26_2/src/main/java/com/lishid/openinv/internal/paper26_2/container/slot/OpenInventoryFactory.java

@@ -0,0 +1,95 @@
+package com.lishid.openinv.internal.paper26_2.container.slot;
+
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.lishid.openinv.internal.paper26_3.container.slot.ContentCrafting;
+import com.lishid.openinv.internal.paper26_3.container.slot.ContentCursor;
+import com.lishid.openinv.internal.paper26_3.container.slot.ContentDrop;
+import com.lishid.openinv.internal.paper26_3.container.slot.ContentViewOnly;
+import com.lishid.openinv.internal.paper26_3.container.slot.SlotViewOnly;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public class OpenInventoryFactory extends com.lishid.openinv.internal.paper26_3.container.slot.OpenInventoryFactory {
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newCrafting(
+      ServerPlayer holder,
+      int index
+  ) {
+    return new ContentCrafting(holder, index) {
+      @Override
+      public void set(ItemStack itemStack) {
+        if (isAvailable(holder)) {
+          items.set(index, itemStack);
+          holder.inventoryMenu.slotsChanged(holder.inventoryMenu.getCraftSlots());
+        } else {
+          this.holder.drop(itemStack, false);
+        }
+      }
+    };
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newCursor(ServerPlayer holder) {
+    return new ContentCursor(holder) {
+      @Override
+      public void set(ItemStack itemStack) {
+        if (isAvailable()) {
+          holder.containerMenu.setCarried(itemStack);
+        } else {
+          this.holder.drop(itemStack, false);
+        }
+      }
+    };
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newDrop(ServerPlayer holder) {
+    return new ContentDrop(holder) {
+      @Override
+      public void set(ItemStack itemStack) {
+        this.holder.drop(itemStack, false);
+      }
+    };
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newViewOnly(ServerPlayer holder) {
+    return newViewOnly(holder, Placeholders.notSlot);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newViewOnly(
+      ServerPlayer holder,
+      ItemStack itemStack
+  ) {
+    return new ContentViewOnly(holder) {
+      @Override
+      public void set(ItemStack itemStack) {
+        this.holder.drop(itemStack, false);
+      }
+
+      @Override
+      public Slot asSlot(Container container, int slot, int x, int y) {
+        return new SlotViewOnly(container, slot, x, y) {
+          @Override
+          public ItemStack getOrDefault() {
+            return itemStack;
+          }
+        };
+      }
+    };
+  }
+
+  @Override
+  public org.bukkit.inventory.ItemStack asBukkitMirror(ItemStack itemStack) {
+    return CraftItemStack.asCraftMirror(itemStack);
+  }
+
+}

internal/paper26_2/src/main/java/com/lishid/openinv/internal/paper26_2/container/slot/SlotViewOnly.java

@@ -1,151 +0,0 @@
-package com.lishid.openinv.internal.paper26_2.container.slot;
-
-import com.lishid.openinv.internal.paper26_2.container.slot.placeholder.Placeholders;
-import net.minecraft.world.Container;
-import net.minecraft.world.entity.player.Player;
-import net.minecraft.world.inventory.Slot;
-import net.minecraft.world.item.ItemStack;
-import org.jetbrains.annotations.NotNull;
-
-import java.util.Optional;
-
-/**
- * A view-only {@link Slot}. "Blank" by default, but can wrap another slot to display its content.
- */
-public class SlotViewOnly extends SlotPlaceholder {
-
-  public static @NotNull SlotViewOnly wrap(@NotNull Slot wrapped) {
-    SlotViewOnly wrapper;
-    if (wrapped instanceof SlotPlaceholder placeholder) {
-      wrapper = new SlotViewOnly(wrapped.container, wrapped.getContainerSlot(), wrapped.x, wrapped.y) {
-        @Override
-        public ItemStack getOrDefault() {
-          return placeholder.getOrDefault();
-        }
-      };
-    } else {
-      wrapper = new SlotViewOnly(wrapped.container, wrapped.getContainerSlot(), wrapped.x, wrapped.y) {
-        @Override
-        public ItemStack getOrDefault() {
-          return wrapped.getItem();
-        }
-      };
-    }
-    wrapper.index = wrapped.index;
-    return wrapper;
-  }
-
-  public SlotViewOnly(Container container, int index, int x, int y) {
-    super(container, index, x, y);
-  }
-
-  @Override
-  public ItemStack getOrDefault() {
-    return Placeholders.notSlot;
-  }
-
-  @Override
-  public void onQuickCraft(@NotNull ItemStack itemStack1, @NotNull ItemStack itemStack2) {
-  }
-
-  @Override
-  public void onTake(@NotNull Player player, @NotNull ItemStack itemStack) {
-  }
-
-  @Override
-  public boolean mayPlace(@NotNull ItemStack itemStack) {
-    return false;
-  }
-
-  @Override
-  public @NotNull ItemStack getItem() {
-    return ItemStack.EMPTY;
-  }
-
-  @Override
-  public boolean hasItem() {
-    return false;
-  }
-
-  @Override
-  public void setByPlayer(@NotNull ItemStack newStack) {
-  }
-
-  @Override
-  public void setByPlayer(@NotNull ItemStack newStack, @NotNull ItemStack oldStack) {
-  }
-
-  @Override
-  public void set(@NotNull ItemStack itemStack) {
-  }
-
-  @Override
-  public void setChanged() {
-  }
-
-  @Override
-  public int getMaxStackSize() {
-    return 0;
-  }
-
-  @Override
-  public int getMaxStackSize(@NotNull ItemStack itemStack) {
-    return 0;
-  }
-
-  @Override
-  public @NotNull ItemStack remove(int amount) {
-    return ItemStack.EMPTY;
-  }
-
-  @Override
-  public boolean mayPickup(@NotNull Player player) {
-    return false;
-  }
-
-  @Override
-  public boolean isActive() {
-    return false;
-  }
-
-  @Override
-  public @NotNull Optional<ItemStack> tryRemove(int var0, int var1, @NotNull Player player) {
-    return Optional.empty();
-  }
-
-  @Override
-  public @NotNull ItemStack safeTake(int var0, int var1, @NotNull Player player) {
-    return ItemStack.EMPTY;
-  }
-
-  @Override
-  public @NotNull ItemStack safeClone(@NotNull Player player) {
-    return ItemStack.EMPTY;
-  }
-
-  @Override
-  public @NotNull ItemStack safeInsert(@NotNull ItemStack itemStack) {
-    return itemStack;
-  }
-
-  @Override
-  public @NotNull ItemStack safeInsert(@NotNull ItemStack itemStack, int amount) {
-    return itemStack;
-  }
-
-  @Override
-  public boolean allowModification(@NotNull Player player) {
-    return false;
-  }
-
-  @Override
-  public boolean isHighlightable() {
-    return false;
-  }
-
-  @Override
-  public boolean isFake() {
-    return true;
-  }
-
-}

internal/paper26_2/src/main/java/com/lishid/openinv/internal/paper26_2/container/slot/placeholder/Placeholders.java

@@ -1,41 +0,0 @@
-package com.lishid.openinv.internal.paper26_2.container.slot.placeholder;
-
-import com.lishid.openinv.internal.paper26_2.player.OpenPlayer;
-import net.minecraft.server.level.ServerPlayer;
-import net.minecraft.world.item.ItemStack;
-import net.minecraft.world.level.GameType;
-import org.jetbrains.annotations.NotNull;
-
-import java.util.EnumMap;
-
-public final class Placeholders {
-
-  // N.B. Slot#getNoItemIcon is still clientside, unfortunately.
-  // Worth checking every few updates just in case - it would be nice to
-  // get rid of some of the placeholders.
-
-  static final @NotNull EnumMap<GameType, ItemStack> BLOCKED_GAME_TYPE = new EnumMap<>(GameType.class);
-  public static @NotNull ItemStack craftingOutput = ItemStack.EMPTY;
-  public static @NotNull ItemStack cursor = ItemStack.EMPTY;
-  public static @NotNull ItemStack drop = ItemStack.EMPTY;
-  public static @NotNull ItemStack emptyHelmet = ItemStack.EMPTY;
-  public static @NotNull ItemStack emptyChestplate = ItemStack.EMPTY;
-  public static @NotNull ItemStack emptyLeggings = ItemStack.EMPTY;
-  public static @NotNull ItemStack emptyBoots = ItemStack.EMPTY;
-  public static @NotNull ItemStack emptyOffHand = ItemStack.EMPTY;
-  public static @NotNull ItemStack notSlot = ItemStack.EMPTY;
-  public static @NotNull ItemStack blockedOffline = ItemStack.EMPTY;
-
-  public static ItemStack survivalOnly(@NotNull ServerPlayer serverPlayer) {
-    if (!OpenPlayer.isConnected(serverPlayer.connection)) {
-      return blockedOffline;
-    }
-
-    return BLOCKED_GAME_TYPE.getOrDefault(serverPlayer.gameMode.getGameModeForPlayer(), ItemStack.EMPTY);
-  }
-
-  private Placeholders() {
-    throw new IllegalStateException("Cannot create instance of utility class.");
-  }
-
-}

internal/paper26_3/build.gradle.kts

@@ -0,0 +1,42 @@
+plugins {
+  alias(libs.plugins.paperweight)
+}
+
+repositories {
+  maven("https://repo.papermc.io/repository/maven-public/")
+}
+
+// Paper is compiled with Java 25, so we have to use a Java 25 toolchain.
+java {
+  toolchain.languageVersion.set(JavaLanguageVersion.of(25))
+}
+
+// To minimize duplicate code, the adapter for 1.21.11 is built off of this module, so we need to target Java 21.
+tasks.withType<JavaCompile>().configureEach {
+  options.release = 21
+}
+
+// As a result, we have to specifically tell Gradle it's okay if our dependencies require Java 25,
+// because secretly sometimes they don't!
+configurations.matching { it.isCanBeResolved && it.name.endsWith("Classpath") }.all {
+  attributes {
+    attribute(TargetJvmVersion.TARGET_JVM_VERSION_ATTRIBUTE, 25)
+  }
+}
+
+dependencies {
+  implementation(project(":openinvapi")) {
+    exclude(group = "org.spigotmc", module = "spigot-api")
+  }
+  implementation(project(":openinvcommon")) {
+    exclude(group = "org.spigotmc", module = "spigot-api")
+  }
+
+  paperweight.paperDevBundle("26.3.build.+")
+}
+
+tasks.reobfJar {
+  enabled = false
+}
+
+configurations.reobf.get().outgoing.artifacts.clear()

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/InternalAccessor.java

@@ -0,0 +1,111 @@
+package com.lishid.openinv.internal.paper26_3;
+
+import com.github.jikoo.openinv.internal.Accessor;
+import com.lishid.openinv.internal.IAnySilentContainer;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.AnySilentContainer;
+import com.lishid.openinv.internal.paper26_3.container.OpenEnderChest;
+import com.lishid.openinv.internal.paper26_3.container.OpenInventory;
+import com.lishid.openinv.internal.paper26_3.container.slot.OpenInventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.PlaceholderLoader;
+import com.lishid.openinv.internal.paper26_3.player.PlayerManager;
+import com.github.jikoo.openinv.lang.LanguageManager;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+@NullMarked
+public class InternalAccessor implements Accessor {
+
+  protected final Logger logger;
+  private final PlayerManager manager;
+  protected final InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory;
+  private final AnySilentContainer anySilentContainer;
+
+  public InternalAccessor(Logger logger, LanguageManager lang) {
+    this.logger = logger;
+    factory = createInventoryFactory();
+    manager = createPlayerManager(logger, factory);
+    anySilentContainer = createAnySilentContainer(logger, lang);
+  }
+
+  protected InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> createInventoryFactory() {
+    return new OpenInventoryFactory();
+  }
+
+  protected PlayerManager createPlayerManager(
+      Logger logger,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory
+  ) {
+    return new PlayerManager(logger, factory);
+  }
+
+  protected AnySilentContainer createAnySilentContainer(
+      Logger logger,
+      LanguageManager lang
+  ) {
+    return new AnySilentContainer(logger, lang);
+  }
+
+  protected PlaceholderLoader createPlaceholderLoader() {
+    return new PlaceholderLoader();
+  }
+
+  @Override
+  public PlayerManager getPlayerManager() {
+    return manager;
+  }
+
+  @Override
+  public IAnySilentContainer getAnySilentContainer() {
+    return anySilentContainer;
+  }
+
+  @Override
+  public ISpecialPlayerInventory createPlayerInventory(Player player) {
+    return new OpenInventory(factory, player);
+  }
+
+  @Override
+  public ISpecialEnderChest createEnderChest(Player player) {
+    return new OpenEnderChest(player);
+  }
+
+  @Override
+  public <T extends ISpecialInventory> @Nullable T get(Inventory bukkitInventory, Class<T> clazz) {
+    if (!(bukkitInventory instanceof CraftInventory craftInventory)) {
+      return null;
+    }
+    Container container = craftInventory.getInventory();
+    if (clazz.isInstance(container)) {
+      return clazz.cast(container);
+    }
+    return null;
+  }
+
+  @Override
+  public void reload(ConfigurationSection config) {
+    ConfigurationSection placeholders = config.getConfigurationSection("placeholders");
+    try {
+      // Reset placeholders to defaults and try to load configuration.
+      createPlaceholderLoader().load(placeholders);
+    } catch (Exception e) {
+      logger.log(Level.WARNING, "Caught exception loading placeholder overrides!", e);
+    }
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/AnySilentContainer.java

@@ -14,13 +14,13 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-package com.lishid.openinv.internal.paper26_2.container;
+package com.lishid.openinv.internal.paper26_3.container;
 
-import com.lishid.openinv.internal.AnySilentContainerBase;
-import com.lishid.openinv.internal.paper26_2.container.menu.OpenChestMenu;
-import com.lishid.openinv.internal.paper26_2.player.PlayerManager;
-import com.lishid.openinv.util.ReflectionHelper;
-import com.lishid.openinv.util.lang.LanguageManager;
+import com.github.jikoo.openinv.internal.container.AnySilentContainerBase;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
+import com.lishid.openinv.internal.paper26_3.player.PlayerManager;
+import com.github.jikoo.openinv.util.ReflectionHelper;
+import com.github.jikoo.openinv.lang.LanguageManager;
 import net.minecraft.core.BlockPos;
 import net.minecraft.network.chat.Component;
 import net.minecraft.server.level.ServerPlayer;
@@ -47,19 +47,20 @@ import org.bukkit.Statistic;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.Inventory;
 import org.bukkit.inventory.InventoryHolder;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.lang.reflect.Field;
 import java.util.logging.Logger;
 
+@NullMarked
 public class AnySilentContainer extends AnySilentContainerBase {
 
-  private final @NotNull Logger logger;
-  private final @NotNull LanguageManager lang;
+  private final Logger logger;
+  private final LanguageManager lang;
   private @Nullable Field serverPlayerGameModeGameType;
 
-  public AnySilentContainer(@NotNull Logger logger, @NotNull LanguageManager lang) {
+  public AnySilentContainer(Logger logger, LanguageManager lang) {
     this.logger = logger;
     this.lang = lang;
     try {
@@ -81,9 +82,9 @@ public class AnySilentContainer extends AnySilentContainerBase {
 
   @Override
   public boolean activateContainer(
-      @NotNull final Player bukkitPlayer,
+      final Player bukkitPlayer,
       final boolean silentchest,
-      @NotNull final org.bukkit.block.Block bukkitBlock
+      final org.bukkit.block.Block bukkitBlock
   ) {
 
     // Silent ender chest is API-only
@@ -120,7 +121,7 @@ public class AnySilentContainer extends AnySilentContainerBase {
       return true;
     }
 
-    if (!(blockEntity instanceof MenuProvider menuProvider)) {
+    if (!(blockEntity instanceof @Nullable MenuProvider menuProvider)) {
       return false;
     }
 
@@ -177,12 +178,12 @@ public class AnySilentContainer extends AnySilentContainerBase {
     return true;
   }
 
-  protected boolean hasLootTable(@NotNull RandomizableContainerBlockEntity lootable) {
+  protected boolean hasLootTable(RandomizableContainerBlockEntity lootable) {
     return lootable.getLootTable() != null;
   }
 
   @Override
-  public void deactivateContainer(@NotNull final Player bukkitPlayer) {
+  public void deactivateContainer(final Player bukkitPlayer) {
     if (this.serverPlayerGameModeGameType == null || bukkitPlayer.getGameMode() == GameMode.SPECTATOR) {
       return;
     }
@@ -220,12 +221,12 @@ public class AnySilentContainer extends AnySilentContainerBase {
   }
 
   @Override
-  protected org.bukkit.block.BlockState getState(@NotNull org.bukkit.block.Block block) {
+  protected org.bukkit.block.BlockState getState(org.bukkit.block.Block block) {
     return block.getState(false);
   }
 
   @Override
-  protected InventoryHolder getHolder(@NotNull Inventory inventory) {
+  protected @Nullable InventoryHolder getHolder(Inventory inventory) {
     return inventory.getHolder(false);
   }
 

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/BaseOpenInventory.java

@@ -1,22 +1,14 @@
-package com.lishid.openinv.internal.paper26_2.container;
+package com.lishid.openinv.internal.paper26_3.container;
 
 import com.lishid.openinv.internal.ISpecialPlayerInventory;
-import com.lishid.openinv.internal.InternalOwned;
-import com.lishid.openinv.internal.paper26_2.container.bukkit.OpenPlayerInventory;
-import com.lishid.openinv.internal.paper26_2.container.menu.OpenChestMenu;
-import com.lishid.openinv.internal.paper26_2.container.menu.OpenInventoryMenu;
-import com.lishid.openinv.internal.paper26_2.container.slot.Content;
-import com.lishid.openinv.internal.paper26_2.container.slot.ContentCrafting;
-import com.lishid.openinv.internal.paper26_2.container.slot.ContentCraftingResult;
-import com.lishid.openinv.internal.paper26_2.container.slot.ContentCursor;
-import com.lishid.openinv.internal.paper26_2.container.slot.ContentDrop;
-import com.lishid.openinv.internal.paper26_2.container.slot.ContentEquipment;
-import com.lishid.openinv.internal.paper26_2.container.slot.ContentList;
-import com.lishid.openinv.internal.paper26_2.container.slot.ContentOffHand;
-import com.lishid.openinv.internal.paper26_2.container.slot.ContentViewOnly;
-import com.lishid.openinv.internal.paper26_2.container.slot.SlotViewOnly;
-import com.lishid.openinv.internal.paper26_2.container.slot.placeholder.Placeholders;
-import com.lishid.openinv.internal.paper26_2.player.PlayerManager;
+import com.github.jikoo.openinv.internal.container.InternalOwned;
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.bukkit.OpenPlayerInventory;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenInventoryMenu;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import com.lishid.openinv.internal.paper26_3.player.PlayerManager;
 import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
 import net.minecraft.core.NonNullList;
 import net.minecraft.network.chat.Component;
@@ -32,31 +24,37 @@ import org.bukkit.craftbukkit.entity.CraftHumanEntity;
 import org.bukkit.craftbukkit.inventory.CraftInventory;
 import org.bukkit.entity.HumanEntity;
 import org.bukkit.event.inventory.InventoryType;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 
+@NullMarked
 public abstract class BaseOpenInventory implements Container, InternalOwned<ServerPlayer>, ISpecialPlayerInventory {
 
-  protected final List<Content> slots;
+  protected final InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory;
+  protected final List<Content<ServerPlayer, ItemStack, Container, Slot>> slots;
   private final int size;
   protected ServerPlayer owner;
   private int maxStackSize = 99;
-  protected CraftInventory bukkitEntity;
+  protected @Nullable CraftInventory bukkitEntity;
   public List<HumanEntity> transaction = new ArrayList<>();
 
-  public BaseOpenInventory(@NotNull org.bukkit.entity.Player bukkitPlayer) {
+  public BaseOpenInventory(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      org.bukkit.entity.Player bukkitPlayer
+  ) {
+    this.factory = factory;
     owner = PlayerManager.getHandle(bukkitPlayer);
 
     // Get total size, rounding up to nearest 9 for client compatibility.
     int rawSize = owner.getInventory().getContainerSize() + owner.inventoryMenu.getCraftSlots().getContainerSize() + 1;
     size = ((int) Math.ceil(rawSize / 9.0)) * 9;
 
-    slots = NonNullList.withSize(size, new ContentViewOnly(owner));
+    slots = NonNullList.withSize(size, factory.newViewOnly(owner));
     setupSlots();
   }
 
@@ -74,9 +72,9 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
       // Off-hand: Below chestplate.
       addOffHand(46);
       // Drop slot: Bottom right.
-      slots.set(53, new ContentDrop(owner));
+      slots.set(53, factory.newDrop(owner));
       // Cursor slot: Above drop.
-      slots.set(44, new ContentCursor(owner));
+      slots.set(44, factory.newCursor(owner));
 
       // Crafting is displayed in the bottom right corner.
       // As we're using the pretty view, this is a 3x2.
@@ -88,9 +86,9 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
     nextIndex = addArmor(nextIndex);
     nextIndex = addOffHand(nextIndex);
     nextIndex = addCrafting(nextIndex, false);
-    slots.set(nextIndex, new ContentCursor(owner));
+    slots.set(nextIndex, factory.newCursor(owner));
     // Drop slot last.
-    slots.set(slots.size() - 1, new ContentDrop(owner));
+    slots.set(slots.size() - 1, factory.newDrop(owner));
   }
 
   private int addMainInventory() {
@@ -111,12 +109,7 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
 
       slots.set(
           localIndex,
-          new ContentList(owner, invIndex, type) {
-            @Override
-            public void setHolder(@NotNull ServerPlayer holder) {
-              items = holder.getInventory().getNonEquipmentItems();
-            }
-          }
+          factory.newList(owner, invIndex, type, holder -> holder.getInventory().getNonEquipmentItems())
       );
     }
     return listSize;
@@ -138,7 +131,7 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
         continue;
       }
 
-      slots.set(startIndex + localIndex, new ContentEquipment(owner, sorted[i]));
+      slots.set(startIndex + localIndex, factory.newEquipment(owner, sorted[i]));
       ++localIndex;
     }
 
@@ -151,7 +144,7 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
       return startIndex;
     }
 
-    slots.set(startIndex, new ContentOffHand(owner));
+    slots.set(startIndex, factory.newOffHand(owner));
     return startIndex + 1;
   }
 
@@ -165,32 +158,17 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
       // Otherwise, subtract 2 and add 9 to start in the same position on the next row.
       int modIndex = startIndex + (localIndex < 2 || !pretty ? localIndex : localIndex + 7);
 
-      slots.set(modIndex, new ContentCrafting(owner, localIndex));
+      slots.set(modIndex, factory.newCrafting(owner, localIndex));
     }
 
     if (pretty) {
-      slots.set(startIndex + 2, new ContentViewOnly(owner) {
-            @Override
-            public Slot asSlot(Container container, int slot, int x, int y) {
-              return new SlotViewOnly(container, slot, x, y) {
-                @Override
-                public ItemStack getOrDefault() {
-                  return Placeholders.craftingOutput;
-                }
-              };
-            }
-          }
-      );
-      slots.set(startIndex + 11, getCraftingResult(owner));
+      slots.set(startIndex + 2, factory.newViewOnly(owner, Placeholders.craftingOutput));
+      slots.set(startIndex + 11, factory.newCraftingResult(owner));
     }
 
     return startIndex + listSize;
   }
 
-  protected Content getCraftingResult(@NotNull ServerPlayer serverPlayer) {
-    return new ContentCraftingResult(serverPlayer);
-  }
-
   public Slot getMenuSlot(int index, int x, int y) {
     return slots.get(index).asSlot(this, index, x, y);
   }
@@ -207,7 +185,7 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
   }
 
   @Override
-  public @NotNull org.bukkit.inventory.Inventory getBukkitInventory() {
+  public org.bukkit.inventory.Inventory getBukkitInventory() {
     if (bukkitEntity == null) {
       bukkitEntity = new OpenPlayerInventory(this);
     }
@@ -215,7 +193,7 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
   }
 
   @Override
-  public void setPlayerOnline(@NotNull org.bukkit.entity.Player player) {
+  public void setPlayerOnline(org.bukkit.entity.Player player) {
     ServerPlayer newOwner = PlayerManager.getHandle(player);
     // Only transfer regular inventory - crafting and cursor slots are transient.
     newOwner.getInventory().replaceWith(owner.getInventory());
@@ -230,7 +208,7 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
   }
 
   @Override
-  public @NotNull org.bukkit.entity.Player getPlayer() {
+  public org.bukkit.entity.Player getPlayer() {
     return getOwner();
   }
 
@@ -245,22 +223,22 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
   }
 
   @Override
-  public @NotNull ItemStack getItem(int index) {
+  public ItemStack getItem(int index) {
     return slots.get(index).get();
   }
 
   @Override
-  public @NotNull ItemStack removeItem(int index, int amount) {
+  public ItemStack removeItem(int index, int amount) {
     return slots.get(index).removePartial(amount);
   }
 
   @Override
-  public @NotNull ItemStack removeItemNoUpdate(int index) {
+  public ItemStack removeItemNoUpdate(int index) {
     return slots.get(index).remove();
   }
 
   @Override
-  public void setItem(int index, @NotNull ItemStack itemStack) {
+  public void setItem(int index, ItemStack itemStack) {
     slots.get(index).set(itemStack);
   }
 
@@ -279,12 +257,12 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
   }
 
   @Override
-  public boolean stillValid(@NotNull Player player) {
+  public boolean stillValid(Player player) {
     return true;
   }
 
   @Override
-  public @NotNull List<ItemStack> getContents() {
+  public List<ItemStack> getContents() {
     NonNullList<ItemStack> contents = NonNullList.withSize(getContainerSize(), ItemStack.EMPTY);
     for (int i = 0; i < getContainerSize(); ++i) {
       contents.set(i, getItem(i));
@@ -293,22 +271,22 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
   }
 
   @Override
-  public void onOpen(@NotNull CraftHumanEntity viewer) {
+  public void onOpen(CraftHumanEntity viewer) {
     transaction.add(viewer);
   }
 
   @Override
-  public void onClose(@NotNull CraftHumanEntity viewer) {
+  public void onClose(CraftHumanEntity viewer) {
     transaction.remove(viewer);
   }
 
   @Override
-  public @NotNull List<HumanEntity> getViewers() {
+  public List<HumanEntity> getViewers() {
     return transaction;
   }
 
   @Override
-  public @NotNull org.bukkit.entity.Player getOwner() {
+  public org.bukkit.entity.Player getOwner() {
     return owner.getBukkitEntity();
   }
 
@@ -327,7 +305,7 @@ public abstract class BaseOpenInventory implements Container, InternalOwned<Serv
 
   public @Nullable OpenChestMenu<?> createMenu(Player player, int i, boolean viewOnly) {
     if (player instanceof ServerPlayer serverPlayer) {
-      return new OpenInventoryMenu(this, serverPlayer, i, viewOnly);
+      return new OpenInventoryMenu(factory, this, serverPlayer, i, viewOnly);
     }
     return null;
   }

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/OpenEnderChest.java

@@ -1,18 +1,21 @@
-package com.lishid.openinv.internal.paper26_2.container;
+package com.lishid.openinv.internal.paper26_3.container;
 
 import com.lishid.openinv.internal.ISpecialEnderChest;
-import com.lishid.openinv.internal.InternalOwned;
-import com.lishid.openinv.internal.paper26_2.container.menu.OpenChestMenu;
-import com.lishid.openinv.internal.paper26_2.container.menu.OpenEnderChestMenu;
-import com.lishid.openinv.internal.paper26_2.player.PlayerManager;
+import com.github.jikoo.openinv.internal.container.InternalOwned;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenEnderChestMenu;
+import com.lishid.openinv.internal.paper26_3.player.PlayerManager;
 import net.minecraft.core.NonNullList;
 import net.minecraft.network.chat.Component;
 import net.minecraft.network.chat.MutableComponent;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.Container;
 import net.minecraft.world.ContainerHelper;
+import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.entity.player.StackedItemContents;
+import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.inventory.StackedContentsCompatible;
 import net.minecraft.world.item.ItemStack;
 import org.bukkit.Location;
@@ -20,37 +23,38 @@ import org.bukkit.craftbukkit.entity.CraftHumanEntity;
 import org.bukkit.craftbukkit.inventory.CraftInventory;
 import org.bukkit.entity.HumanEntity;
 import org.bukkit.event.inventory.InventoryType;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.List;
 
+@NullMarked
 public class OpenEnderChest implements Container, StackedContentsCompatible, InternalOwned<ServerPlayer>,
     ISpecialEnderChest {
 
-  private CraftInventory inventory;
-  private @NotNull ServerPlayer owner;
+  private @Nullable CraftInventory inventory;
+  private ServerPlayer owner;
   private NonNullList<ItemStack> items;
   private int maxStack = 64;
   private final List<HumanEntity> transaction = new ArrayList<>();
 
-  public OpenEnderChest(@NotNull org.bukkit.entity.Player player) {
+  public OpenEnderChest(org.bukkit.entity.Player player) {
     this.owner = PlayerManager.getHandle(player);
     this.items = getEnderChestItems(owner);
   }
 
   @Override
-  public @NotNull ServerPlayer getOwnerHandle() {
+  public ServerPlayer getOwnerHandle() {
     return owner;
   }
 
   @Override
-  public @NotNull org.bukkit.inventory.Inventory getBukkitInventory() {
+  public org.bukkit.inventory.Inventory getBukkitInventory() {
     if (inventory == null) {
       inventory = new CraftInventory(this) {
         @Override
-        public @NotNull InventoryType getType() {
+        public InventoryType getType() {
           return InventoryType.ENDER_CHEST;
         }
       };
@@ -59,7 +63,7 @@ public class OpenEnderChest implements Container, StackedContentsCompatible, Int
   }
 
   @Override
-  public void setPlayerOnline(@NotNull org.bukkit.entity.Player player) {
+  public void setPlayerOnline(org.bukkit.entity.Player player) {
     owner = PlayerManager.getHandle(player);
     NonNullList<ItemStack> activeItems = getEnderChestItems(owner);
 
@@ -72,12 +76,12 @@ public class OpenEnderChest implements Container, StackedContentsCompatible, Int
     items = activeItems;
   }
 
-  protected @NotNull NonNullList<ItemStack> getEnderChestItems(@NotNull ServerPlayer owner) {
+  protected NonNullList<ItemStack> getEnderChestItems(ServerPlayer owner) {
     return owner.getEnderChestInventory().getItems();
   }
 
   @Override
-  public @NotNull org.bukkit.entity.Player getPlayer() {
+  public org.bukkit.entity.Player getPlayer() {
     return owner.getBukkitEntity();
   }
 
@@ -92,12 +96,12 @@ public class OpenEnderChest implements Container, StackedContentsCompatible, Int
   }
 
   @Override
-  public @NotNull ItemStack getItem(int index) {
+  public ItemStack getItem(int index) {
     return index >= 0 && index < items.size() ? items.get(index) : ItemStack.EMPTY;
   }
 
   @Override
-  public @NotNull ItemStack removeItem(int index, int amount) {
+  public ItemStack removeItem(int index, int amount) {
     ItemStack itemstack = ContainerHelper.removeItem(items, index, amount);
 
     if (!itemstack.isEmpty()) {
@@ -108,12 +112,12 @@ public class OpenEnderChest implements Container, StackedContentsCompatible, Int
   }
 
   @Override
-  public @NotNull ItemStack removeItemNoUpdate(int index) {
+  public ItemStack removeItemNoUpdate(int index) {
     return index >= 0 && index < items.size() ? items.set(index, ItemStack.EMPTY) : ItemStack.EMPTY;
   }
 
   @Override
-  public void setItem(int index, @NotNull ItemStack itemStack) {
+  public void setItem(int index, ItemStack itemStack) {
     if (index >= 0 && index < items.size()) {
       items.set(index, itemStack);
     }
@@ -130,27 +134,27 @@ public class OpenEnderChest implements Container, StackedContentsCompatible, Int
   }
 
   @Override
-  public boolean stillValid(@NotNull Player player) {
+  public boolean stillValid(Player player) {
     return true;
   }
 
   @Override
-  public @NotNull List<ItemStack> getContents() {
+  public List<ItemStack> getContents() {
     return items;
   }
 
   @Override
-  public void onOpen(@NotNull CraftHumanEntity craftHumanEntity) {
+  public void onOpen(CraftHumanEntity craftHumanEntity) {
     transaction.add(craftHumanEntity);
   }
 
   @Override
-  public void onClose(@NotNull CraftHumanEntity craftHumanEntity) {
+  public void onClose(CraftHumanEntity craftHumanEntity) {
     transaction.remove(craftHumanEntity);
   }
 
   @Override
-  public @NotNull List<HumanEntity> getViewers() {
+  public List<HumanEntity> getViewers() {
     return transaction;
   }
 
@@ -176,7 +180,7 @@ public class OpenEnderChest implements Container, StackedContentsCompatible, Int
   }
 
   @Override
-  public void fillStackedContents(@NotNull StackedItemContents stackedContents) {
+  public void fillStackedContents(StackedItemContents stackedContents) {
     for (ItemStack itemstack : items) {
       stackedContents.accountStack(itemstack);
     }
@@ -195,9 +199,14 @@ public class OpenEnderChest implements Container, StackedContentsCompatible, Int
         .append(Component.translatableWithFallback("openinv.container.enderchest.suffix", " - %s", owner.getName()));
   }
 
-  public @Nullable OpenChestMenu<?> createMenu(Player player, int i, boolean viewOnly) {
+  public @Nullable OpenChestMenu<?> createMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      Player player,
+      int i,
+      boolean viewOnly
+  ) {
     if (player instanceof ServerPlayer serverPlayer) {
-      return new OpenEnderChestMenu(this, serverPlayer, i, viewOnly);
+      return new OpenEnderChestMenu(factory, this, serverPlayer, i, viewOnly);
     }
     return null;
   }

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/OpenInventory.java

@@ -1,24 +1,33 @@
-package com.lishid.openinv.internal.paper26_2.container;
+package com.lishid.openinv.internal.paper26_3.container;
 
-import com.lishid.openinv.internal.paper26_2.container.menu.OpenChestMenu;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
 import net.minecraft.ChatFormatting;
 import net.minecraft.network.chat.Component;
 import net.minecraft.network.chat.FontDescription;
 import net.minecraft.network.chat.MutableComponent;
 import net.minecraft.resources.Identifier;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
 import org.bukkit.entity.Player;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
+@NullMarked
 public class OpenInventory extends BaseOpenInventory {
 
-  public OpenInventory(@NotNull Player bukkitPlayer) {
-    super(bukkitPlayer);
+  public OpenInventory(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      Player bukkitPlayer
+  ) {
+    super(factory, bukkitPlayer);
   }
 
   @Override
-  public @NotNull Component getTitle(@Nullable ServerPlayer viewer, @Nullable OpenChestMenu<?> menu) {
+  public Component getTitle(@Nullable ServerPlayer viewer, @Nullable OpenChestMenu<?> menu) {
     MutableComponent component = Component.empty();
     // Prefix for use with custom bitmap image fonts.
     if (owner.equals(viewer)) {

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/bukkit/OpenDummyInventory.java

@@ -1,13 +1,13 @@
-package com.lishid.openinv.internal.paper26_2.container.bukkit;
+package com.lishid.openinv.internal.paper26_3.container.bukkit;
 
-import com.lishid.openinv.internal.ViewOnly;
+import com.github.jikoo.openinv.internal.container.ViewOnly;
 import net.minecraft.world.Container;
 import org.bukkit.Material;
 import org.bukkit.craftbukkit.inventory.CraftInventory;
 import org.bukkit.event.inventory.InventoryType;
 import org.bukkit.inventory.ItemStack;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.Collections;
 import java.util.HashMap;
@@ -16,6 +16,7 @@ import java.util.ListIterator;
 /**
  * A locked down "empty" inventory that rejects plugin interaction.
  */
+@NullMarked
 public class OpenDummyInventory extends CraftInventory implements ViewOnly {
 
   private final InventoryType type;
@@ -26,7 +27,7 @@ public class OpenDummyInventory extends CraftInventory implements ViewOnly {
   }
 
   @Override
-  public @NotNull InventoryType getType() {
+  public InventoryType getType() {
     return type;
   }
 
@@ -42,18 +43,18 @@ public class OpenDummyInventory extends CraftInventory implements ViewOnly {
 
   @SuppressWarnings("NonApiType")
   @Override
-  public @NotNull HashMap<Integer, ItemStack> addItem(@NotNull ItemStack... items) throws IllegalArgumentException {
+  public HashMap<Integer, ItemStack> addItem(ItemStack... items) throws IllegalArgumentException {
     return arrayToHashMap(items);
   }
 
   @SuppressWarnings("NonApiType")
   @Override
-  public @NotNull HashMap<Integer, ItemStack> removeItem(@NotNull ItemStack... items) throws IllegalArgumentException {
+  public HashMap<Integer, ItemStack> removeItem(ItemStack... items) throws IllegalArgumentException {
     return arrayToHashMap(items);
   }
 
   @SuppressWarnings("NonApiType")
-  private static @NotNull HashMap<Integer, ItemStack> arrayToHashMap(@NotNull ItemStack[] items) {
+  private static HashMap<Integer, ItemStack> arrayToHashMap(ItemStack[] items) {
     HashMap<Integer, ItemStack> ignored = new HashMap<>();
     for (int index = 0; index < items.length; ++index) {
       ignored.put(index, items[index]);
@@ -62,27 +63,27 @@ public class OpenDummyInventory extends CraftInventory implements ViewOnly {
   }
 
   @Override
-  public ItemStack @NotNull [] getContents() {
+  public ItemStack[] getContents() {
     return new ItemStack[getSize()];
   }
 
   @Override
-  public void setContents(@NotNull ItemStack[] items) throws IllegalArgumentException {
+  public void setContents(ItemStack[] items) throws IllegalArgumentException {
 
   }
 
   @Override
-  public @NotNull ItemStack @NotNull [] getStorageContents() {
+  public ItemStack[] getStorageContents() {
     return new ItemStack[getSize()];
   }
 
   @Override
-  public void setStorageContents(@NotNull ItemStack[] items) throws IllegalArgumentException {
+  public void setStorageContents(ItemStack[] items) throws IllegalArgumentException {
 
   }
 
   @Override
-  public boolean contains(@NotNull Material material) throws IllegalArgumentException {
+  public boolean contains(Material material) throws IllegalArgumentException {
     return false;
   }
 
@@ -92,7 +93,7 @@ public class OpenDummyInventory extends CraftInventory implements ViewOnly {
   }
 
   @Override
-  public boolean contains(@NotNull Material material, int amount) throws IllegalArgumentException {
+  public boolean contains(Material material, int amount) throws IllegalArgumentException {
     return false;
   }
 
@@ -108,25 +109,25 @@ public class OpenDummyInventory extends CraftInventory implements ViewOnly {
 
   @SuppressWarnings("NonApiType")
   @Override
-  public @NotNull HashMap<Integer, ItemStack> all(
-      @NotNull Material material
+  public HashMap<Integer, ItemStack> all(
+      Material material
   ) throws IllegalArgumentException {
     return new HashMap<>();
   }
 
   @SuppressWarnings("NonApiType")
   @Override
-  public @NotNull HashMap<Integer, ItemStack> all(@Nullable ItemStack item) {
+  public HashMap<Integer, ItemStack> all(@Nullable ItemStack item) {
     return new HashMap<>();
   }
 
   @Override
-  public int first(@NotNull Material material) throws IllegalArgumentException {
+  public int first(Material material) throws IllegalArgumentException {
     return -1;
   }
 
   @Override
-  public int first(@NotNull ItemStack item) {
+  public int first(ItemStack item) {
     return -1;
   }
 
@@ -141,12 +142,12 @@ public class OpenDummyInventory extends CraftInventory implements ViewOnly {
   }
 
   @Override
-  public void remove(@NotNull Material material) throws IllegalArgumentException {
+  public void remove(Material material) throws IllegalArgumentException {
 
   }
 
   @Override
-  public void remove(@NotNull ItemStack item) {
+  public void remove(ItemStack item) {
 
   }
 
@@ -161,12 +162,12 @@ public class OpenDummyInventory extends CraftInventory implements ViewOnly {
   }
 
   @Override
-  public @NotNull ListIterator<ItemStack> iterator() {
+  public ListIterator<ItemStack> iterator() {
     return Collections.emptyListIterator();
   }
 
   @Override
-  public @NotNull ListIterator<ItemStack> iterator(int index) {
+  public ListIterator<ItemStack> iterator(int index) {
     return Collections.emptyListIterator();
   }
 

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/bukkit/OpenDummyPlayerInventory.java

@@ -1,15 +1,15 @@
-package com.lishid.openinv.internal.paper26_2.container.bukkit;
+package com.lishid.openinv.internal.paper26_3.container.bukkit;
 
 import net.minecraft.world.Container;
-import org.bukkit.Material;
 import org.bukkit.entity.HumanEntity;
 import org.bukkit.event.inventory.InventoryType;
 import org.bukkit.inventory.EquipmentSlot;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.PlayerInventory;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
+@NullMarked
 public class OpenDummyPlayerInventory extends OpenDummyInventory implements PlayerInventory {
 
   public OpenDummyPlayerInventory(Container inventory) {
@@ -22,52 +22,52 @@ public class OpenDummyPlayerInventory extends OpenDummyInventory implements Play
   }
 
   @Override
-  public @NotNull ItemStack @NotNull [] getArmorContents() {
+  public ItemStack[] getArmorContents() {
     return new ItemStack[4];
   }
 
   @Override
-  public @NotNull ItemStack @NotNull [] getExtraContents() {
+  public ItemStack[] getExtraContents() {
     return new ItemStack[4];
   }
 
   @Override
-  public @Nullable ItemStack getHelmet() {
-    return null;
+  public ItemStack getHelmet() {
+    return ItemStack.empty();
   }
 
   @Override
-  public @Nullable ItemStack getChestplate() {
-    return null;
+  public ItemStack getChestplate() {
+    return ItemStack.empty();
   }
 
   @Override
-  public @Nullable ItemStack getLeggings() {
-    return null;
+  public ItemStack getLeggings() {
+    return ItemStack.empty();
   }
 
   @Override
-  public @Nullable ItemStack getBoots() {
-    return null;
+  public ItemStack getBoots() {
+    return ItemStack.empty();
   }
 
   @Override
-  public void setItem(@NotNull EquipmentSlot slot, @Nullable ItemStack item) {
+  public void setItem(EquipmentSlot slot, @Nullable ItemStack item) {
 
   }
 
   @Override
-  public @NotNull ItemStack getItem(@NotNull EquipmentSlot slot) {
-    return new ItemStack(Material.AIR);
+  public ItemStack getItem(EquipmentSlot slot) {
+    return ItemStack.empty();
   }
 
   @Override
-  public void setArmorContents(ItemStack @NotNull [] items) {
+  public void setArmorContents(@Nullable ItemStack[] items) {
 
   }
 
   @Override
-  public void setExtraContents(ItemStack @NotNull [] items) {
+  public void setExtraContents(@Nullable ItemStack[] items) {
 
   }
 
@@ -92,8 +92,8 @@ public class OpenDummyPlayerInventory extends OpenDummyInventory implements Play
   }
 
   @Override
-  public @NotNull ItemStack getItemInMainHand() {
-    return new ItemStack(Material.AIR);
+  public ItemStack getItemInMainHand() {
+    return ItemStack.empty();
   }
 
   @Override
@@ -102,8 +102,8 @@ public class OpenDummyPlayerInventory extends OpenDummyInventory implements Play
   }
 
   @Override
-  public @NotNull ItemStack getItemInOffHand() {
-    return new ItemStack(Material.AIR);
+  public ItemStack getItemInOffHand() {
+    return ItemStack.empty();
   }
 
   @Override
@@ -114,8 +114,8 @@ public class OpenDummyPlayerInventory extends OpenDummyInventory implements Play
   @SuppressWarnings("InlineMeSuggester")
   @Deprecated
   @Override
-  public @NotNull ItemStack getItemInHand() {
-    return new ItemStack(Material.AIR);
+  public ItemStack getItemInHand() {
+    return ItemStack.empty();
   }
 
   @Deprecated

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/bukkit/OpenPlayerInventory.java

@@ -1,7 +1,7 @@
-package com.lishid.openinv.internal.paper26_2.container.bukkit;
+package com.lishid.openinv.internal.paper26_3.container.bukkit;
 
 import com.google.common.base.Preconditions;
-import com.lishid.openinv.internal.paper26_2.container.BaseOpenInventory;
+import com.lishid.openinv.internal.paper26_3.container.BaseOpenInventory;
 import net.minecraft.core.NonNullList;
 import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.player.Inventory;
@@ -11,29 +11,30 @@ import org.bukkit.entity.Player;
 import org.bukkit.event.inventory.InventoryType;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.PlayerInventory;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.List;
 
+@NullMarked
 public class OpenPlayerInventory extends CraftInventory implements PlayerInventory {
 
-  public OpenPlayerInventory(@NotNull BaseOpenInventory inventory) {
+  public OpenPlayerInventory(BaseOpenInventory inventory) {
     super(inventory);
   }
 
   @Override
-  public @NotNull BaseOpenInventory getInventory() {
+  public BaseOpenInventory getInventory() {
     return (BaseOpenInventory) super.getInventory();
   }
 
   @Override
-  public ItemStack @NotNull [] getContents() {
+  public ItemStack[] getContents() {
     return asCraftMirror(getInventory().getOwnerHandle().getInventory().getContents());
   }
 
   @Override
-  public void setContents(ItemStack[] items) {
+  public void setContents(@Nullable ItemStack[] items) {
     Inventory internal = getInventory().getOwnerHandle().getInventory();
     int size = internal.getContainerSize();
     Preconditions.checkArgument(items.length <= size, "items.length must be <= %s", size);
@@ -48,12 +49,12 @@ public class OpenPlayerInventory extends CraftInventory implements PlayerInvento
   }
 
   @Override
-  public ItemStack @NotNull [] getStorageContents() {
+  public ItemStack[] getStorageContents() {
     return asCraftMirror(getInventory().getOwnerHandle().getInventory().getNonEquipmentItems());
   }
 
   @Override
-  public void setStorageContents(ItemStack[] items) throws IllegalArgumentException {
+  public void setStorageContents(@Nullable ItemStack[] items) throws IllegalArgumentException {
     NonNullList<net.minecraft.world.item.ItemStack> list = getInventory().getOwnerHandle().getInventory().getNonEquipmentItems();
     int size = list.size();
     Preconditions.checkArgument(items.length <= size, "items.length must be <= %s", size);
@@ -63,22 +64,22 @@ public class OpenPlayerInventory extends CraftInventory implements PlayerInvento
   }
 
   @Override
-  public @NotNull InventoryType getType() {
+  public InventoryType getType() {
     return InventoryType.PLAYER;
   }
 
   @Override
-  public @NotNull Player getHolder() {
+  public Player getHolder() {
     return getInventory().getOwner();
   }
 
   @Override
-  public @NotNull ItemStack @NotNull [] getArmorContents() {
+  public ItemStack[] getArmorContents() {
     return asCraftMirror(getInventory().getOwnerHandle().getInventory().getArmorContents());
   }
 
   @Override
-  public void setArmorContents(ItemStack @NotNull [] items) {
+  public void setArmorContents(@Nullable ItemStack[] items) {
     int size = Inventory.EQUIPMENT_SLOTS_SORTED_BY_INDEX.length;
     Preconditions.checkArgument(items.length <= size, "items.length must be <= %s", size);
     for (int index = 0; index < items.length; ++index) {
@@ -90,12 +91,12 @@ public class OpenPlayerInventory extends CraftInventory implements PlayerInvento
   }
 
   @Override
-  public @NotNull ItemStack @NotNull [] getExtraContents() {
+  public ItemStack[] getExtraContents() {
     return asCraftMirror(List.of(getInventory().getOwnerHandle().getInventory().equipment.get(EquipmentSlot.OFFHAND)));
   }
 
   @Override
-  public void setExtraContents(ItemStack @NotNull [] items) {
+  public void setExtraContents(@Nullable ItemStack[] items) {
     Preconditions.checkArgument(items.length <= 1, "items.length must be <= 1");
     for (ItemStack item : items) {
       getInventory().getOwnerHandle().getInventory().equipment.set(EquipmentSlot.OFFHAND, CraftItemStack.asNMSCopy(item));
@@ -103,81 +104,69 @@ public class OpenPlayerInventory extends CraftInventory implements PlayerInvento
   }
 
   @Override
-  public @NotNull ItemStack getHelmet() {
-    return CraftItemStack.asCraftMirror(getInventory().getOwnerHandle().getInventory().equipment
-        .get(EquipmentSlot.HEAD));
+  public ItemStack getHelmet() {
+    return getInventory().getOwner().getInventory().getHelmet();
   }
 
   @Override
   public void setHelmet(@Nullable ItemStack helmet) {
-    getInventory().getOwnerHandle().getInventory().equipment
-        .set(EquipmentSlot.HEAD, CraftItemStack.asNMSCopy(helmet));
+    getInventory().getOwner().getInventory().setHelmet(helmet);
   }
 
   @Override
-  public @NotNull ItemStack getChestplate() {
-    return CraftItemStack.asCraftMirror(getInventory().getOwnerHandle().getInventory().equipment
-        .get(EquipmentSlot.CHEST));
+  public ItemStack getChestplate() {
+    return getInventory().getOwner().getInventory().getChestplate();
   }
 
   @Override
   public void setChestplate(@Nullable ItemStack chestplate) {
-    getInventory().getOwnerHandle().getInventory().equipment
-        .set(EquipmentSlot.CHEST, CraftItemStack.asNMSCopy(chestplate));
+    getInventory().getOwner().getInventory().setChestplate(chestplate);
   }
 
   @Override
-  public @NotNull ItemStack getLeggings() {
-    return CraftItemStack.asCraftMirror(getInventory().getOwnerHandle().getInventory().equipment
-        .get(EquipmentSlot.LEGS));
+  public ItemStack getLeggings() {
+    return getInventory().getOwner().getInventory().getLeggings();
   }
 
   @Override
   public void setLeggings(@Nullable ItemStack leggings) {
-    getInventory().getOwnerHandle().getInventory().equipment
-        .set(EquipmentSlot.LEGS, CraftItemStack.asNMSCopy(leggings));
+    getInventory().getOwner().getInventory().setLeggings(leggings);
   }
 
   @Override
-  public @NotNull ItemStack getBoots() {
-    return CraftItemStack.asCraftMirror(getInventory().getOwnerHandle().getInventory().equipment
-        .get(EquipmentSlot.FEET));
+  public ItemStack getBoots() {
+    return getInventory().getOwner().getInventory().getBoots();
   }
 
   @Override
   public void setBoots(@Nullable ItemStack boots) {
-    getInventory().getOwnerHandle().getInventory().equipment
-        .set(EquipmentSlot.FEET, CraftItemStack.asNMSCopy(boots));
+    getInventory().getOwner().getInventory().setBoots(boots);
   }
 
   @Override
-  public @NotNull ItemStack getItemInMainHand() {
-    Inventory internal = getInventory().getOwnerHandle().getInventory();
-    return CraftItemStack.asCraftMirror(internal.getSelectedItem());
+  public ItemStack getItemInMainHand() {
+    return getInventory().getOwner().getInventory().getItemInMainHand();
   }
 
   @Override
   public void setItemInMainHand(@Nullable ItemStack item) {
-    Inventory internal = getInventory().getOwnerHandle().getInventory();
-    internal.setSelectedItem(CraftItemStack.asNMSCopy(item));
+    getInventory().getOwner().getInventory().setItemInMainHand(item);
   }
 
   @Override
-  public @NotNull ItemStack getItemInOffHand() {
-    return CraftItemStack.asCraftMirror(getInventory().getOwnerHandle().getInventory().equipment
-        .get(EquipmentSlot.OFFHAND));
+  public ItemStack getItemInOffHand() {
+    return getInventory().getOwner().getInventory().getItemInOffHand();
   }
 
   @Override
   public void setItemInOffHand(@Nullable ItemStack item) {
-    getInventory().getOwnerHandle().getInventory().equipment
-        .set(EquipmentSlot.OFFHAND, CraftItemStack.asNMSCopy(item));
+    getInventory().getOwner().getInventory().setItemInOffHand(item);
   }
 
   @SuppressWarnings("InlineMeSuggester")
   @Deprecated
   @Override
-  public @NotNull ItemStack getItemInHand() {
+  public ItemStack getItemInHand() {
     return getItemInMainHand();
   }
 
@@ -201,7 +190,7 @@ public class OpenPlayerInventory extends CraftInventory implements PlayerInvento
   }
 
   @Override
-  public @NotNull ItemStack getItem(@NotNull org.bukkit.inventory.EquipmentSlot slot) {
+  public ItemStack getItem(org.bukkit.inventory.EquipmentSlot slot) {
     return switch (slot) {
       case HAND -> getItemInMainHand();
       case OFF_HAND -> getItemInOffHand();
@@ -214,7 +203,7 @@ public class OpenPlayerInventory extends CraftInventory implements PlayerInvento
   }
 
   @Override
-  public void setItem(@NotNull org.bukkit.inventory.EquipmentSlot slot, @Nullable ItemStack item) {
+  public void setItem(org.bukkit.inventory.EquipmentSlot slot, @Nullable ItemStack item) {
     switch (slot) {
       case HAND -> setItemInMainHand(item);
       case OFF_HAND -> setItemInOffHand(item);

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/bukkit/OpenPlayerInventorySelf.java

@@ -0,0 +1,28 @@
+package com.lishid.openinv.internal.paper26_3.container.bukkit;
+
+import com.lishid.openinv.internal.paper26_3.container.BaseOpenInventory;
+import org.bukkit.inventory.ItemStack;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+public class OpenPlayerInventorySelf extends OpenPlayerInventory {
+
+  private final int offset;
+
+  public OpenPlayerInventorySelf(BaseOpenInventory inventory, int offset) {
+    super(inventory);
+    this.offset = offset;
+  }
+
+  @Override
+  public @Nullable ItemStack getItem(int index) {
+    return super.getItem(offset + index);
+  }
+
+  @Override
+  public void setItem(int index, @Nullable ItemStack item) {
+    super.setItem(offset + index, item);
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/menu/BaseOpenInventoryMenu.java

@@ -1,14 +1,16 @@
-package com.lishid.openinv.internal.paper26_2.container.menu;
+package com.lishid.openinv.internal.paper26_3.container.menu;
 
 import com.google.common.base.Preconditions;
-import com.lishid.openinv.internal.paper26_2.container.BaseOpenInventory;
-import com.lishid.openinv.internal.paper26_2.container.bukkit.OpenDummyPlayerInventory;
-import com.lishid.openinv.internal.paper26_2.container.bukkit.OpenPlayerInventorySelf;
-import com.lishid.openinv.internal.paper26_2.container.slot.ContentDrop;
-import com.lishid.openinv.internal.paper26_2.container.slot.ContentEquipment;
-import com.lishid.openinv.internal.paper26_2.container.slot.SlotViewOnly;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.BaseOpenInventory;
+import com.lishid.openinv.internal.paper26_3.container.bukkit.OpenDummyPlayerInventory;
+import com.lishid.openinv.internal.paper26_3.container.bukkit.OpenPlayerInventorySelf;
+import com.lishid.openinv.internal.paper26_3.container.slot.ContentDrop;
+import com.lishid.openinv.internal.paper26_3.container.slot.SlotEquipment;
+import com.lishid.openinv.internal.paper26_3.container.slot.SlotViewOnly;
 import com.lishid.openinv.util.Permissions;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
 import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.inventory.ChestMenu;
@@ -16,7 +18,6 @@ import net.minecraft.world.inventory.MenuType;
 import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.item.ItemStack;
 import org.bukkit.craftbukkit.inventory.CraftInventoryView;
-import org.bukkit.craftbukkit.inventory.CraftItemStack;
 import org.bukkit.event.inventory.InventoryType;
 import org.bukkit.inventory.Inventory;
 import org.bukkit.inventory.InventoryView;
@@ -28,8 +29,14 @@ public class BaseOpenInventoryMenu extends OpenSyncMenu<BaseOpenInventory> {
 
   private int offset;
 
-  public BaseOpenInventoryMenu(BaseOpenInventory inventory, ServerPlayer viewer, int i, boolean viewOnly) {
-    super(getMenuType(inventory, viewer), i, inventory, viewer, viewOnly);
+  public BaseOpenInventoryMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      BaseOpenInventory inventory,
+      ServerPlayer viewer,
+      int i,
+      boolean viewOnly
+  ) {
+    super(getMenuType(inventory, viewer), i, factory, inventory, viewer, viewOnly);
   }
 
   private static MenuType<ChestMenu> getMenuType(BaseOpenInventory inventory, ServerPlayer viewer) {
@@ -64,9 +71,9 @@ public class BaseOpenInventoryMenu extends OpenSyncMenu<BaseOpenInventory> {
       return new SlotViewOnly(container, index, x, y);
     }
 
-    if (slot instanceof ContentEquipment.SlotEquipment equipment) {
+    if (slot instanceof SlotEquipment equipment) {
       if (viewOnly) {
-        return SlotViewOnly.wrap(slot);
+        return factory.wrapViewOnly(slot);
       }
 
       Permissions perm = switch (equipment.getEquipmentSlot()) {
@@ -93,7 +100,7 @@ public class BaseOpenInventoryMenu extends OpenSyncMenu<BaseOpenInventory> {
     }
 
     if (viewOnly) {
-      return SlotViewOnly.wrap(slot);
+      return factory.wrapViewOnly(slot);
     }
 
     return slot;
@@ -118,7 +125,7 @@ public class BaseOpenInventoryMenu extends OpenSyncMenu<BaseOpenInventory> {
         }
 
         Slot slot = slots.get(index);
-        return CraftItemStack.asCraftMirror(slot.hasItem() ? slot.getItem() : ItemStack.EMPTY);
+        return factory.asBukkitMirror(slot.hasItem() ? slot.getItem() : ItemStack.EMPTY);
       }
 
       @Override
@@ -227,7 +234,7 @@ public class BaseOpenInventoryMenu extends OpenSyncMenu<BaseOpenInventory> {
           // Locate the correct slot in the contents following the main inventory.
           for (int extra = container.getOwnerHandle().getInventory().getNonEquipmentItems().size() - offset; extra < topSize; ++extra) {
             Slot extraSlot = getSlot(extra);
-            if (extraSlot instanceof ContentEquipment.SlotEquipment equipSlot
+            if (extraSlot instanceof SlotEquipment equipSlot
                 && equipSlot.getEquipmentSlot() == equipmentSlot) {
               // If we've found a matching slot, try to move to it.
               // If this succeeds, even partially, we will not attempt to move to other slots.

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/menu/OpenChestMenu.java

@@ -1,11 +1,13 @@
-package com.lishid.openinv.internal.paper26_2.container.menu;
+package com.lishid.openinv.internal.paper26_3.container.menu;
 
 import com.lishid.openinv.internal.ISpecialInventory;
-import com.lishid.openinv.internal.InternalOwned;
-import com.lishid.openinv.internal.paper26_2.container.bukkit.OpenDummyInventory;
-import com.lishid.openinv.internal.paper26_2.container.slot.SlotViewOnly;
+import com.github.jikoo.openinv.internal.container.InternalOwned;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.bukkit.OpenDummyInventory;
+import com.lishid.openinv.internal.paper26_3.container.slot.SlotViewOnly;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.inventory.AbstractContainerMenu;
 import net.minecraft.world.inventory.ChestMenu;
@@ -28,6 +30,7 @@ public abstract class OpenChestMenu<T extends Container & ISpecialInventory & In
 
   protected static final int BOTTOM_INVENTORY_SIZE = 36;
 
+  protected final InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory;
   protected final T container;
   protected final ServerPlayer viewer;
   protected final boolean viewOnly;
@@ -38,11 +41,13 @@ public abstract class OpenChestMenu<T extends Container & ISpecialInventory & In
   protected OpenChestMenu(
       MenuType<ChestMenu> type,
       int containerCounter,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
       T container,
       ServerPlayer viewer,
       boolean viewOnly
   ) {
     super(type, containerCounter);
+    this.factory = factory;
     this.container = container;
     this.viewer = viewer;
     this.viewOnly = viewOnly;
@@ -109,7 +114,7 @@ public abstract class OpenChestMenu<T extends Container & ISpecialInventory & In
   protected Slot getUpperSlot(int index, int x, int y) {
     Slot slot = new Slot(container, index, x, y);
     if (viewOnly) {
-      return SlotViewOnly.wrap(slot);
+      return factory.wrapViewOnly(slot);
     }
     return slot;
   }
@@ -163,17 +168,17 @@ public abstract class OpenChestMenu<T extends Container & ISpecialInventory & In
 
   private int getTopSize(ServerPlayer viewer) {
     MenuType<?> menuType = getType();
-    if (menuType == MenuType.GENERIC_9x1) {
+    if (MenuType.GENERIC_9x1.equals(menuType)) {
       return 9;
-    } else if (menuType == MenuType.GENERIC_9x2) {
+    } else if (MenuType.GENERIC_9x2.equals(menuType)) {
       return 18;
-    } else if (menuType == MenuType.GENERIC_9x3) {
+    } else if (MenuType.GENERIC_9x3.equals(menuType)) {
       return 27;
-    } else if (menuType == MenuType.GENERIC_9x4) {
+    } else if (MenuType.GENERIC_9x4.equals(menuType)) {
       return 36;
-    } else if (menuType == MenuType.GENERIC_9x5) {
+    } else if (MenuType.GENERIC_9x5.equals(menuType)) {
       return 45;
-    } else if (menuType == MenuType.GENERIC_9x6) {
+    } else if (MenuType.GENERIC_9x6.equals(menuType)) {
       return 54;
     }
     // This is a bit gross, but allows us a safe fallthrough.

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/menu/OpenEnderChestMenu.java

@@ -1,7 +1,10 @@
-package com.lishid.openinv.internal.paper26_2.container.menu;
+package com.lishid.openinv.internal.paper26_3.container.menu;
 
-import com.lishid.openinv.internal.paper26_2.container.OpenEnderChest;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.OpenEnderChest;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.inventory.ContainerInput;
 import net.minecraft.world.inventory.Slot;
@@ -12,12 +15,13 @@ import org.jspecify.annotations.NullMarked;
 public class OpenEnderChestMenu extends OpenSyncMenu<OpenEnderChest> {
 
   public OpenEnderChestMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
       OpenEnderChest enderChest,
       ServerPlayer viewer,
       int containerId,
       boolean viewOnly
   ) {
-    super(getChestMenuType(enderChest.getContainerSize()), containerId, enderChest, viewer, viewOnly);
+    super(getChestMenuType(enderChest.getContainerSize()), containerId, factory, enderChest, viewer, viewOnly);
   }
 
   @Override

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/menu/OpenInventoryMenu.java

@@ -0,0 +1,37 @@
+package com.lishid.openinv.internal.paper26_3.container.menu;
+
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.BaseOpenInventory;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.ContainerInput;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+public class OpenInventoryMenu extends BaseOpenInventoryMenu {
+
+  public OpenInventoryMenu(
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
+      BaseOpenInventory inventory,
+      ServerPlayer viewer,
+      int i,
+      boolean viewOnly
+  ) {
+    super(factory, inventory, viewer, i, viewOnly);
+  }
+
+  @Override
+  public void clicked(int slotIndex, int buttonNum, ContainerInput containerInput, Player player) {
+    if (viewOnly) {
+      if (containerInput == ContainerInput.QUICK_CRAFT) {
+        sendAllDataToRemote();
+      }
+    }
+    super.clicked(slotIndex, buttonNum, containerInput, player);
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/menu/OpenSyncMenu.java

@@ -1,11 +1,13 @@
-package com.lishid.openinv.internal.paper26_2.container.menu;
+package com.lishid.openinv.internal.paper26_3.container.menu;
 
 import com.google.common.base.Suppliers;
 import com.lishid.openinv.internal.ISpecialInventory;
-import com.lishid.openinv.internal.InternalOwned;
-import com.lishid.openinv.internal.paper26_2.container.slot.SlotPlaceholder;
+import com.github.jikoo.openinv.internal.container.InternalOwned;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.slot.SlotPlaceholder;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.inventory.AbstractContainerMenu;
 import net.minecraft.world.inventory.ChestMenu;
 import net.minecraft.world.inventory.ContainerListener;
@@ -41,11 +43,12 @@ public abstract class OpenSyncMenu<T extends Container & ISpecialInventory & Int
   protected OpenSyncMenu(
       MenuType<ChestMenu> type,
       int containerCounter,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory,
       T container,
       ServerPlayer viewer,
       boolean viewOnly
   ) {
-    super(type, containerCounter, container, viewer, viewOnly);
+    super(type, containerCounter, factory, container, viewer, viewOnly);
   }
 
   @Override

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentCrafting.java

@@ -1,37 +1,36 @@
-package com.lishid.openinv.internal.paper26_2.container.slot;
+package com.lishid.openinv.internal.paper26_3.container.slot;
 
-import com.lishid.openinv.internal.paper26_2.container.slot.placeholder.Placeholders;
-import com.lishid.openinv.internal.paper26_2.player.OpenPlayer;
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import com.lishid.openinv.internal.paper26_3.player.OpenPlayer;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.util.Prediction;
 import net.minecraft.world.Container;
 import net.minecraft.world.ContainerHelper;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.item.ItemStack;
 import org.bukkit.event.inventory.InventoryType;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.List;
 
 /**
  * A slot in a survival crafting inventory. Unavailable when not online in a survival mode.
  */
-public class ContentCrafting implements Content {
+@NullMarked
+public class ContentCrafting implements Content<ServerPlayer, ItemStack, Container, Slot> {
 
   private final int index;
-  private ServerPlayer holder;
-  private List<ItemStack> items;
+  protected ServerPlayer holder;
+  protected List<ItemStack> items;
 
-  public ContentCrafting(@NotNull ServerPlayer holder, int index) {
+  protected ContentCrafting(ServerPlayer holder, int index) {
     setHolder(holder);
     this.index = index;
   }
 
-  private boolean isAvailable() {
-    return isAvailable(holder);
-  }
-
-  public static boolean isAvailable(@NotNull ServerPlayer holder) {
+  public static boolean isAvailable(ServerPlayer holder) {
     // Player must be online and not in creative - since the creative client is (semi-)authoritative,
     // it ignores changes without extra help, and will delete the item as a result.
     // Spectator mode is technically possible but may cause the item to be dropped if the client opens an inventory.
@@ -39,7 +38,7 @@ public class ContentCrafting implements Content {
   }
 
   @Override
-  public void setHolder(@NotNull ServerPlayer holder) {
+  public void setHolder(ServerPlayer holder) {
     this.holder = holder;
     // Note: CraftingContainer#getItems is immutable! Be careful with updates.
     this.items = holder.inventoryMenu.getCraftSlots().getContents();
@@ -47,12 +46,12 @@ public class ContentCrafting implements Content {
 
   @Override
   public ItemStack get() {
-    return isAvailable() ? items.get(index) : ItemStack.EMPTY;
+    return isAvailable(holder) ? items.get(index) : ItemStack.EMPTY;
   }
 
   @Override
   public ItemStack remove() {
-    if (!this.isAvailable()) {
+    if (!isAvailable(holder)) {
       return ItemStack.EMPTY;
     }
     ItemStack removed = items.remove(index);
@@ -65,7 +64,7 @@ public class ContentCrafting implements Content {
 
   @Override
   public ItemStack removePartial(int amount) {
-    if (!this.isAvailable()) {
+    if (!isAvailable(holder)) {
       return ItemStack.EMPTY;
     }
     ItemStack removed = ContainerHelper.removeItem(items, index, amount);
@@ -78,11 +77,11 @@ public class ContentCrafting implements Content {
 
   @Override
   public void set(ItemStack itemStack) {
-    if (isAvailable()) {
+    if (isAvailable(holder)) {
       items.set(index, itemStack);
       holder.inventoryMenu.slotsChanged(holder.inventoryMenu.getCraftSlots());
     } else {
-      holder.drop(itemStack, false);
+      this.holder.drop(itemStack, false, Prediction.SERVER_ONLY);
     }
   }
 
@@ -93,7 +92,7 @@ public class ContentCrafting implements Content {
 
   @Override
   public InventoryType.SlotType getSlotType() {
-    return isAvailable() ? InventoryType.SlotType.CRAFTING : InventoryType.SlotType.OUTSIDE;
+    return isAvailable(holder) ? InventoryType.SlotType.CRAFTING : InventoryType.SlotType.OUTSIDE;
   }
 
   public class SlotCrafting extends SlotPlaceholder {
@@ -104,27 +103,27 @@ public class ContentCrafting implements Content {
 
     @Override
     public ItemStack getOrDefault() {
-      return isAvailable() ? items.get(ContentCrafting.this.index) : Placeholders.survivalOnly(holder);
+      return isAvailable(holder) ? items.get(ContentCrafting.this.index) : Placeholders.survivalOnly(holder);
     }
 
     @Override
-    public boolean mayPickup(@NotNull Player player) {
-      return isAvailable();
+    public boolean mayPickup(Player player) {
+      return isAvailable(holder);
     }
 
     @Override
-    public boolean mayPlace(@NotNull ItemStack itemStack) {
-      return isAvailable();
+    public boolean mayPlace(ItemStack itemStack) {
+      return isAvailable(holder);
     }
 
     @Override
     public boolean hasItem() {
-      return isAvailable() && super.hasItem();
+      return isAvailable(holder) && super.hasItem();
     }
 
     @Override
     public boolean isFake() {
-      return !isAvailable();
+      return !isAvailable(holder);
     }
 
   }

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentCraftingResult.java

@@ -1,22 +1,23 @@
-package com.lishid.openinv.internal.paper26_2.container.slot;
+package com.lishid.openinv.internal.paper26_3.container.slot;
 
-import com.lishid.openinv.internal.paper26_2.container.slot.placeholder.Placeholders;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.Container;
 import net.minecraft.world.inventory.InventoryMenu;
 import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.item.ItemStack;
 import org.bukkit.event.inventory.InventoryType;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * A slot allowing viewing of the crafting result.
  *
  * <p>Unmodifiable because I said so. Use your own crafting grid.</p>
  */
-public class ContentCraftingResult extends ContentViewOnly {
+@NullMarked
+class ContentCraftingResult extends ContentViewOnly {
 
-  public ContentCraftingResult(@NotNull ServerPlayer holder) {
+  ContentCraftingResult(ServerPlayer holder) {
     super(holder);
   }
 

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentCursor.java

@@ -1,28 +1,31 @@
-package com.lishid.openinv.internal.paper26_2.container.slot;
+package com.lishid.openinv.internal.paper26_3.container.slot;
 
-import com.lishid.openinv.internal.paper26_2.container.slot.placeholder.Placeholders;
-import com.lishid.openinv.internal.paper26_2.player.OpenPlayer;
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import com.lishid.openinv.internal.paper26_3.player.OpenPlayer;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.util.Prediction;
 import net.minecraft.world.Container;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.item.ItemStack;
 import org.bukkit.event.inventory.InventoryType;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * A slot wrapping the active menu's cursor. Unavailable when not online in a survival mode.
  */
-public class ContentCursor implements Content {
+@NullMarked
+public class ContentCursor implements Content<ServerPlayer, ItemStack, Container, Slot> {
 
-  private @NotNull ServerPlayer holder;
+  protected ServerPlayer holder;
 
-  public ContentCursor(@NotNull ServerPlayer holder) {
+  protected ContentCursor(ServerPlayer holder) {
     this.holder = holder;
   }
 
   @Override
-  public void setHolder(@NotNull ServerPlayer holder) {
+  public void setHolder(ServerPlayer holder) {
     this.holder = holder;
   }
 
@@ -56,11 +59,11 @@ public class ContentCursor implements Content {
     if (isAvailable()) {
       holder.containerMenu.setCarried(itemStack);
     } else {
-      holder.drop(itemStack, false);
+      this.holder.drop(itemStack, false, Prediction.SERVER_ONLY);
     }
   }
 
-  private boolean isAvailable() {
+  protected boolean isAvailable() {
     // Player must be online and not in creative - since the creative client is (semi-)authoritative,
     // it ignores changes without extra help, and will delete the item as a result.
     // Spectator mode is technically possible but may cause the item to be dropped if the client opens an inventory.
@@ -94,12 +97,12 @@ public class ContentCursor implements Content {
     }
 
     @Override
-    public boolean mayPickup(@NotNull Player player) {
+    public boolean mayPickup(Player player) {
       return isAvailable();
     }
 
     @Override
-    public boolean mayPlace(@NotNull ItemStack itemStack) {
+    public boolean mayPlace(ItemStack itemStack) {
       return isAvailable();
     }
 

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentDrop.java

@@ -1,27 +1,30 @@
-package com.lishid.openinv.internal.paper26_2.container.slot;
+package com.lishid.openinv.internal.paper26_3.container.slot;
 
-import com.lishid.openinv.internal.paper26_2.container.slot.placeholder.Placeholders;
-import com.lishid.openinv.internal.paper26_2.player.OpenPlayer;
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import com.lishid.openinv.internal.paper26_3.player.OpenPlayer;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.util.Prediction;
 import net.minecraft.world.Container;
 import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.item.ItemStack;
 import org.bukkit.event.inventory.InventoryType;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * A fake slot used to drop items. Unavailable offline.
  */
-public class ContentDrop implements Content {
+@NullMarked
+public class ContentDrop implements Content<ServerPlayer, ItemStack, Container, Slot> {
 
-  private ServerPlayer holder;
+  protected ServerPlayer holder;
 
-  public ContentDrop(@NotNull ServerPlayer holder) {
+  protected ContentDrop(ServerPlayer holder) {
     this.holder = holder;
   }
 
   @Override
-  public void setHolder(@NotNull ServerPlayer holder) {
+  public void setHolder(ServerPlayer holder) {
     this.holder = holder;
   }
 
@@ -42,7 +45,7 @@ public class ContentDrop implements Content {
 
   @Override
   public void set(ItemStack itemStack) {
-    holder.drop(itemStack, true);
+    this.holder.drop(itemStack, false, Prediction.SERVER_ONLY);
   }
 
   @Override
@@ -70,7 +73,7 @@ public class ContentDrop implements Content {
     }
 
     @Override
-    public boolean mayPlace(@NotNull ItemStack itemStack) {
+    public boolean mayPlace(ItemStack itemStack) {
       return OpenPlayer.isConnected(holder.connection);
     }
 

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentEquipment.java

@@ -1,6 +1,7 @@
-package com.lishid.openinv.internal.paper26_2.container.slot;
+package com.lishid.openinv.internal.paper26_3.container.slot;
 
-import com.lishid.openinv.internal.paper26_2.container.slot.placeholder.Placeholders;
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.Container;
 import net.minecraft.world.entity.EntityEquipment;
@@ -8,18 +9,19 @@ import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.item.ItemStack;
 import org.bukkit.event.inventory.InventoryType;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * A slot for equipment that displays placeholders if empty.
  */
-public class ContentEquipment implements Content {
+@NullMarked
+class ContentEquipment implements Content<ServerPlayer, ItemStack, Container, Slot> {
 
   private EntityEquipment equipment;
   private final ItemStack placeholder;
   private final EquipmentSlot equipmentSlot;
 
-  public ContentEquipment(ServerPlayer holder, EquipmentSlot equipmentSlot) {
+  ContentEquipment(ServerPlayer holder, EquipmentSlot equipmentSlot) {
     setHolder(holder);
     placeholder = switch (equipmentSlot) {
       case HEAD -> Placeholders.emptyHelmet;
@@ -32,7 +34,7 @@ public class ContentEquipment implements Content {
   }
 
   @Override
-  public void setHolder(@NotNull ServerPlayer holder) {
+  public void setHolder(ServerPlayer holder) {
     this.equipment = holder.getInventory().equipment;
   }
 
@@ -62,7 +64,7 @@ public class ContentEquipment implements Content {
 
   @Override
   public Slot asSlot(Container container, int slot, int x, int y) {
-    return new SlotEquipment(container, slot, x, y);
+    return new SlotEquipment(container, slot, x, y, placeholder, equipmentSlot);
   }
 
   @Override
@@ -70,40 +72,4 @@ public class ContentEquipment implements Content {
     return InventoryType.SlotType.ARMOR;
   }
 
-  public class SlotEquipment extends SlotPlaceholder {
-
-    private ServerPlayer viewer;
-
-    SlotEquipment(Container container, int index, int x, int y) {
-      super(container, index, x, y);
-    }
-
-    @Override
-    public ItemStack getOrDefault() {
-      ItemStack itemStack = getItem();
-      if (!itemStack.isEmpty()) {
-        return itemStack;
-      }
-      return placeholder;
-    }
-
-    public EquipmentSlot getEquipmentSlot() {
-      return equipmentSlot;
-    }
-
-    public void onlyEquipmentFor(ServerPlayer viewer) {
-      this.viewer = viewer;
-    }
-
-    @Override
-    public boolean mayPlace(@NotNull ItemStack itemStack) {
-      if (viewer == null) {
-        return true;
-      }
-
-      return equipmentSlot == EquipmentSlot.OFFHAND || viewer.getEquipmentSlotForItem(itemStack) == equipmentSlot;
-    }
-
-  }
-
 }

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentList.java

@@ -1,29 +1,39 @@
-package com.lishid.openinv.internal.paper26_2.container.slot;
+package com.lishid.openinv.internal.paper26_3.container.slot;
 
+import com.github.jikoo.openinv.internal.container.slot.Content;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.Container;
 import net.minecraft.world.ContainerHelper;
 import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.item.ItemStack;
 import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.List;
 
 /**
  * A normal slot backed by an item list.
  */
-public abstract class ContentList implements Content {
+@NullMarked
+abstract class ContentList implements Content<ServerPlayer, ItemStack, Container, Slot> {
 
   private final int index;
   private final InventoryType.SlotType slotType;
-  protected List<ItemStack> items;
+  private List<ItemStack> items;
 
-  public ContentList(ServerPlayer holder, int index, InventoryType.SlotType slotType) {
+  ContentList(ServerPlayer holder, int index, InventoryType.SlotType slotType) {
     this.index = index;
     this.slotType = slotType;
     setHolder(holder);
   }
 
+  @Override
+  public void setHolder(ServerPlayer holder) {
+    this.items = getItems(holder);
+  }
+
+  protected abstract List<ItemStack> getItems(ServerPlayer holder);
+
   @Override
   public ItemStack get() {
     return items.get(index);
@@ -32,7 +42,7 @@ public abstract class ContentList implements Content {
   @Override
   public ItemStack remove() {
     ItemStack removed = items.remove(index);
-    return removed == null || removed.isEmpty() ? ItemStack.EMPTY : removed;
+    return removed.isEmpty() ? ItemStack.EMPTY : removed;
   }
 
   @Override

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentOffHand.java

@@ -1,6 +1,7 @@
-package com.lishid.openinv.internal.paper26_2.container.slot;
+package com.lishid.openinv.internal.paper26_3.container.slot;
 
-import com.lishid.openinv.internal.paper26_2.player.OpenPlayer;
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import com.lishid.openinv.internal.paper26_3.player.OpenPlayer;
 import net.minecraft.network.protocol.game.ClientboundContainerSetSlotPacket;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.Container;
@@ -8,21 +9,25 @@ import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.inventory.InventoryMenu;
 import net.minecraft.world.inventory.Slot;
 import org.bukkit.event.inventory.InventoryType;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.Objects;
 
 /**
  * A slot for equipment that updates held items if necessary.
  */
-public class ContentOffHand extends ContentEquipment {
+@NullMarked
+class ContentOffHand extends ContentEquipment {
 
   private ServerPlayer holder;
 
-  public ContentOffHand(ServerPlayer holder) {
+  ContentOffHand(ServerPlayer holder) {
     super(holder, EquipmentSlot.OFFHAND);
+    this.holder = holder; // Redundant, but silences nullity warning.
   }
 
   @Override
-  public void setHolder(@NotNull ServerPlayer holder) {
+  public void setHolder(ServerPlayer holder) {
     super.setHolder(holder);
     this.holder = holder;
   }
@@ -34,10 +39,10 @@ public class ContentOffHand extends ContentEquipment {
 
   @Override
   public Slot asSlot(Container container, int slot, int x, int y) {
-    return new SlotEquipment(container, slot, x, y) {
+    return new SlotEquipment(container, slot, x, y, Placeholders.emptyOffHand, EquipmentSlot.OFFHAND) {
       @Override
       public void setChanged() {
-        if (OpenPlayer.isConnected(holder.connection) && holder.containerMenu != holder.inventoryMenu) {
+        if (OpenPlayer.isConnected(holder.connection) && !Objects.equals(holder.containerMenu, holder.inventoryMenu)) {
           holder.connection.send(
               new ClientboundContainerSetSlotPacket(
                   holder.inventoryMenu.containerId,

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/ContentViewOnly.java

@@ -1,25 +1,28 @@
-package com.lishid.openinv.internal.paper26_2.container.slot;
+package com.lishid.openinv.internal.paper26_3.container.slot;
 
+import com.github.jikoo.openinv.internal.container.slot.Content;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.util.Prediction;
 import net.minecraft.world.Container;
 import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.item.ItemStack;
 import org.bukkit.event.inventory.InventoryType;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * A view-only slot that can't be interacted with.
  */
-public class ContentViewOnly implements Content {
+@NullMarked
+public class ContentViewOnly implements Content<ServerPlayer, ItemStack, Container, Slot> {
 
-  protected @NotNull ServerPlayer holder;
+  protected ServerPlayer holder;
 
-  public ContentViewOnly(@NotNull ServerPlayer holder) {
+  protected ContentViewOnly(ServerPlayer holder) {
     this.holder = holder;
   }
 
   @Override
-  public void setHolder(@NotNull ServerPlayer holder) {
+  public void setHolder(ServerPlayer holder) {
     this.holder = holder;
   }
 
@@ -40,7 +43,7 @@ public class ContentViewOnly implements Content {
 
   @Override
   public void set(ItemStack itemStack) {
-    this.holder.drop(itemStack, false);
+    this.holder.drop(itemStack, false, Prediction.SERVER_ONLY);
   }
 
   @Override

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/OpenInventoryFactory.java

@@ -0,0 +1,115 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import com.github.jikoo.openinv.internal.container.slot.Content;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.List;
+import java.util.function.Function;
+
+@NullMarked
+public class OpenInventoryFactory implements InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> {
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newCrafting(ServerPlayer holder, int index) {
+    return new ContentCrafting(holder, index);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newCraftingResult(ServerPlayer holder) {
+    return new ContentCraftingResult(holder);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newCursor(ServerPlayer holder) {
+    return new ContentCursor(holder);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newDrop(ServerPlayer holder) {
+    return new ContentDrop(holder);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newEquipment(
+      ServerPlayer holder,
+      EquipmentSlot equipmentSlot
+  ) {
+    return new ContentEquipment(holder, equipmentSlot);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newList(
+      ServerPlayer holder,
+      int index,
+      InventoryType.SlotType slotType,
+      Function<ServerPlayer, List<ItemStack>> listSupplier
+  ) {
+    return new ContentList(holder, index, slotType) {
+      @Override
+      protected List<ItemStack> getItems(ServerPlayer holder) {
+        return listSupplier.apply(holder);
+      }
+    };
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newOffHand(ServerPlayer holder) {
+    return new ContentOffHand(holder);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newViewOnly(ServerPlayer holder) {
+    return new ContentViewOnly(holder);
+  }
+
+  @Override
+  public Content<ServerPlayer, ItemStack, Container, Slot> newViewOnly(ServerPlayer holder, ItemStack itemStack) {
+    return new ContentViewOnly(holder) {
+      @Override
+      public Slot asSlot(Container container, int slot, int x, int y) {
+        return new SlotViewOnly(container, slot, x, y) {
+          @Override
+          public ItemStack getOrDefault() {
+            return itemStack;
+          }
+        };
+      }
+    };
+  }
+
+  @Override
+  public Slot wrapViewOnly(Slot wrapped) {
+    SlotViewOnly wrapper;
+    if (wrapped instanceof SlotPlaceholder placeholder) {
+      wrapper = new SlotViewOnly(wrapped.container, wrapped.getContainerSlot(), wrapped.x, wrapped.y) {
+        @Override
+        public ItemStack getOrDefault() {
+          return placeholder.getOrDefault();
+        }
+      };
+    } else {
+      wrapper = new SlotViewOnly(wrapped.container, wrapped.getContainerSlot(), wrapped.x, wrapped.y) {
+        @Override
+        public ItemStack getOrDefault() {
+          return wrapped.getItem();
+        }
+      };
+    }
+    wrapper.index = wrapped.index;
+    return wrapper;
+  }
+
+  @Override
+  public org.bukkit.inventory.ItemStack asBukkitMirror(ItemStack itemStack) {
+    return CraftItemStack.asBukkitMirror(itemStack);
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/SlotEquipment.java

@@ -0,0 +1,49 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+public class SlotEquipment extends SlotPlaceholder {
+
+  private final ItemStack placeholder;
+  private final EquipmentSlot equipmentSlot;
+  private @Nullable ServerPlayer viewer;
+
+  SlotEquipment(Container container, int index, int x, int y, ItemStack placeholder, EquipmentSlot equipmentSlot) {
+    super(container, index, x, y);
+    this.placeholder = placeholder;
+    this.equipmentSlot = equipmentSlot;
+  }
+
+  @Override
+  public ItemStack getOrDefault() {
+    ItemStack itemStack = getItem();
+    if (!itemStack.isEmpty()) {
+      return itemStack;
+    }
+    return placeholder;
+  }
+
+  public EquipmentSlot getEquipmentSlot() {
+    return equipmentSlot;
+  }
+
+  public void onlyEquipmentFor(ServerPlayer viewer) {
+    this.viewer = viewer;
+  }
+
+  @Override
+  public boolean mayPlace(ItemStack itemStack) {
+    if (viewer == null) {
+      return true;
+    }
+
+    return equipmentSlot == EquipmentSlot.OFFHAND || viewer.getEquipmentSlotForItem(itemStack) == equipmentSlot;
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/SlotPlaceholder.java

@@ -1,17 +1,19 @@
-package com.lishid.openinv.internal.paper26_2.container.slot;
+package com.lishid.openinv.internal.paper26_3.container.slot;
 
 import net.minecraft.world.Container;
 import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * An implementation of a slot as used by a menu that may have fake placeholder items.
  *
  * <p>Used to prevent plugins (particularly sorting plugins) from adding placeholders to inventories.</p>
  */
+@NullMarked
 public abstract class SlotPlaceholder extends Slot {
 
-  public SlotPlaceholder(Container container, int index, int x, int y) {
+  SlotPlaceholder(Container container, int index, int x, int y) {
     super(container, index, x, y);
   }
 

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/SlotViewOnly.java

@@ -0,0 +1,131 @@
+package com.lishid.openinv.internal.paper26_3.container.slot;
+
+import com.lishid.openinv.internal.paper26_3.container.slot.placeholder.Placeholders;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.Optional;
+
+/**
+ * A view-only {@link Slot}. "Blank" by default, but can wrap another slot to display its content.
+ */
+@NullMarked
+public class SlotViewOnly extends SlotPlaceholder {
+
+  public SlotViewOnly(Container container, int index, int x, int y) {
+    super(container, index, x, y);
+  }
+
+  @Override
+  public ItemStack getOrDefault() {
+    return Placeholders.notSlot;
+  }
+
+  @Override
+  public void onQuickCraft(ItemStack itemStack1, ItemStack itemStack2) {
+  }
+
+  @Override
+  public void onTake(Player player, ItemStack itemStack) {
+  }
+
+  @Override
+  public boolean mayPlace(ItemStack itemStack) {
+    return false;
+  }
+
+  @Override
+  public ItemStack getItem() {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public boolean hasItem() {
+    return false;
+  }
+
+  @Override
+  public void setByPlayer(ItemStack newStack) {
+  }
+
+  @Override
+  public void setByPlayer(ItemStack newStack, ItemStack oldStack) {
+  }
+
+  @Override
+  public void set(ItemStack itemStack) {
+  }
+
+  @Override
+  public void setChanged() {
+  }
+
+  @Override
+  public int getMaxStackSize() {
+    return 0;
+  }
+
+  @Override
+  public int getMaxStackSize(ItemStack itemStack) {
+    return 0;
+  }
+
+  @Override
+  public ItemStack remove(int amount) {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public boolean mayPickup(Player player) {
+    return false;
+  }
+
+  @Override
+  public boolean isActive() {
+    return false;
+  }
+
+  @Override
+  public Optional<ItemStack> tryRemove(int var0, int var1, Player player) {
+    return Optional.empty();
+  }
+
+  @Override
+  public ItemStack safeTake(int var0, int var1, Player player) {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack safeClone(Player player) {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack safeInsert(ItemStack itemStack) {
+    return itemStack;
+  }
+
+  @Override
+  public ItemStack safeInsert(ItemStack itemStack, int amount) {
+    return itemStack;
+  }
+
+  @Override
+  public boolean allowModification(Player player) {
+    return false;
+  }
+
+  @Override
+  public boolean isHighlightable() {
+    return false;
+  }
+
+  @Override
+  public boolean isFake() {
+    return true;
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/placeholder/PlaceholderLoader.java

@@ -1,4 +1,4 @@
-package com.lishid.openinv.internal.paper26_2.container.slot.placeholder;
+package com.lishid.openinv.internal.paper26_3.container.slot.placeholder;
 
 import com.mojang.serialization.DataResult;
 import net.minecraft.core.Registry;
@@ -23,12 +23,13 @@ import net.minecraft.world.level.block.entity.BannerPatternLayers;
 import net.minecraft.world.level.block.entity.BannerPatterns;
 import org.bukkit.configuration.ConfigurationSection;
 import org.bukkit.craftbukkit.CraftRegistry;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.LinkedHashSet;
 import java.util.List;
 
+@NullMarked
 public class PlaceholderLoader {
 
   public void load(@Nullable ConfigurationSection section) throws Exception {
@@ -57,10 +58,10 @@ public class PlaceholderLoader {
     Placeholders.BLOCKED_GAME_TYPE.put(GameType.SPECTATOR, parse(section, "blocked.spectator", Placeholders.BLOCKED_GAME_TYPE.get(GameType.SPECTATOR)));
   }
 
-  protected @NotNull ItemStack parse(
+  protected ItemStack parse(
       @Nullable ConfigurationSection section,
-      @NotNull String path,
-      @NotNull ItemStack defaultStack
+      String path,
+      ItemStack defaultStack
   ) throws Exception {
     if (section == null) {
       return defaultStack;
@@ -86,15 +87,15 @@ public class PlaceholderLoader {
   private static final CustomModelData DEFAULT_CUSTOM_MODEL_DATA = new CustomModelData(List.of(), List.of(), List.of("openinv:custom"), List.of());
   private static final TooltipDisplay HIDE_TOOLTIP = new TooltipDisplay(true, new LinkedHashSet<>());
 
-  protected void addModelData(@NotNull ItemStack itemStack) {
+  protected void addModelData(ItemStack itemStack) {
     itemStack.set(DataComponents.CUSTOM_MODEL_DATA, DEFAULT_CUSTOM_MODEL_DATA);
   }
 
-  protected void hideTooltip(@NotNull ItemStack itemStack) {
+  protected void hideTooltip(ItemStack itemStack) {
     itemStack.set(DataComponents.TOOLTIP_DISPLAY, HIDE_TOOLTIP);
   }
 
-  protected @NotNull ItemStack defaultCraftingOutput() {
+  protected ItemStack defaultCraftingOutput() {
     // Crafting table: "Crafting"
     ItemStack itemStack = new ItemStack(Items.CRAFTING_TABLE);
     itemStack.set(DataComponents.ITEM_NAME, Component.translatable("container.crafting"));
@@ -102,7 +103,7 @@ public class PlaceholderLoader {
     return itemStack;
   }
 
-  protected @NotNull ItemStack defaultCursor() {
+  protected ItemStack defaultCursor() {
     // Cursor-like banner with no tooltip
     ItemStack itemStack = new ItemStack(getDefaultCursorItem());
     RegistryAccess minecraftRegistry = CraftRegistry.getMinecraftRegistry();
@@ -122,7 +123,7 @@ public class PlaceholderLoader {
     return itemStack;
   }
 
-  protected @NotNull ItemStack defaultDrop() {
+  protected ItemStack defaultDrop() {
     // Dropper: "Drop Selected Item"
     ItemStack itemStack = new ItemStack(Items.DROPPER);
     // Note: translatable component, not keybind component! We want the text identifying the keybind, not the key.
@@ -131,7 +132,7 @@ public class PlaceholderLoader {
     return itemStack;
   }
 
-  protected @NotNull ItemStack getEmptyArmor(@NotNull ItemLike item) {
+  protected ItemStack getEmptyArmor(ItemLike item) {
     // Inventory-background-grey-ish leather armor with no tooltip
     ItemStack itemStack = new ItemStack(item);
     DyedItemColor color = new DyedItemColor(0xC8C8C8);
@@ -141,7 +142,7 @@ public class PlaceholderLoader {
     return itemStack;
   }
 
-  protected @NotNull ItemStack defaultShield() {
+  protected ItemStack defaultShield() {
     // Shield with "missing texture" pattern, magenta and black squares.
     ItemStack itemStack = new ItemStack(Items.SHIELD);
     itemStack.set(DataComponents.BASE_COLOR, DyeColor.MAGENTA);
@@ -166,7 +167,7 @@ public class PlaceholderLoader {
     return itemStack;
   }
 
-  protected @NotNull ItemStack defaultNotSlot() {
+  protected ItemStack defaultNotSlot() {
     // White pane with no tooltip
     ItemStack itemStack = new ItemStack(getDefaultNotSlotItem());
     hideTooltip(itemStack);
@@ -174,15 +175,15 @@ public class PlaceholderLoader {
     return itemStack;
   }
 
-  protected @NotNull Item getDefaultCursorItem() {
+  protected Item getDefaultCursorItem() {
     return Items.BANNER.white();
   }
 
-  protected @NotNull Item getDefaultNotSlotItem() {
+  protected Item getDefaultNotSlotItem() {
     return Items.STAINED_GLASS_PANE.white();
   }
 
-  protected @NotNull ItemStack defaultBlockedOffline() {
+  protected ItemStack defaultBlockedOffline() {
     // Barrier: "Not available - Offline"
     ItemStack itemStack = new ItemStack(Items.BARRIER);
     itemStack.set(DataComponents.ITEM_NAME,

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/container/slot/placeholder/Placeholders.java

@@ -0,0 +1,42 @@
+package com.lishid.openinv.internal.paper26_3.container.slot.placeholder;
+
+import com.lishid.openinv.internal.paper26_3.player.OpenPlayer;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.GameType;
+import org.jspecify.annotations.NullMarked;
+
+import java.util.EnumMap;
+
+@NullMarked
+public final class Placeholders {
+
+  // N.B. Slot#getNoItemIcon is still clientside, unfortunately.
+  // Worth checking every few updates just in case - it would be nice to
+  // get rid of some of the placeholders.
+
+  static final EnumMap<GameType, ItemStack> BLOCKED_GAME_TYPE = new EnumMap<>(GameType.class);
+  public static ItemStack craftingOutput = ItemStack.EMPTY;
+  public static ItemStack cursor = ItemStack.EMPTY;
+  public static ItemStack drop = ItemStack.EMPTY;
+  public static ItemStack emptyHelmet = ItemStack.EMPTY;
+  public static ItemStack emptyChestplate = ItemStack.EMPTY;
+  public static ItemStack emptyLeggings = ItemStack.EMPTY;
+  public static ItemStack emptyBoots = ItemStack.EMPTY;
+  public static ItemStack emptyOffHand = ItemStack.EMPTY;
+  public static ItemStack notSlot = ItemStack.EMPTY;
+  public static ItemStack blockedOffline = ItemStack.EMPTY;
+
+  public static ItemStack survivalOnly(ServerPlayer serverPlayer) {
+    if (!OpenPlayer.isConnected(serverPlayer.connection)) {
+      return blockedOffline;
+    }
+
+    return BLOCKED_GAME_TYPE.getOrDefault(serverPlayer.gameMode.getGameModeForPlayer(), ItemStack.EMPTY);
+  }
+
+  private Placeholders() {
+    throw new IllegalStateException("Cannot create instance of utility class.");
+  }
+
+}

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/player/OpenPlayer.java

@@ -1,4 +1,4 @@
-package com.lishid.openinv.internal.paper26_2.player;
+package com.lishid.openinv.internal.paper26_3.player;
 
 import com.lishid.openinv.event.OpenEvents;
 import com.mojang.logging.LogUtils;
@@ -15,9 +15,9 @@ import net.minecraft.world.level.storage.ValueOutput;
 import org.bukkit.craftbukkit.CraftServer;
 import org.bukkit.craftbukkit.entity.CraftPlayer;
 import org.jetbrains.annotations.Contract;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 import org.jetbrains.annotations.Unmodifiable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.slf4j.Logger;
 
 import java.io.IOException;
@@ -25,6 +25,7 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Set;
 
+@NullMarked
 public class OpenPlayer extends CraftPlayer {
 
   /**
@@ -39,6 +40,7 @@ public class OpenPlayer extends CraftPlayer {
   @Unmodifiable
   protected static final Set<String> RESET_TAGS = Set.of(
       // Entity#saveWithoutId(CompoundTag)
+      "invulnerable_time",
       "CustomName",
       "CustomNameVisible",
       "Silent",
@@ -51,7 +53,6 @@ public class OpenPlayer extends CraftPlayer {
       "Passengers",
       // ServerPlayer#addAdditionalSaveData(CompoundTag)
       // Intentional omissions to prevent mount loss: Attach, Entity, and RootVehicle
-      "warden_spawn_tracker", // No longer needed as of 1.21.11
       "entered_nether_pos",
       "last_explosion_impact_pos",
       "respawn",
@@ -112,10 +113,10 @@ public class OpenPlayer extends CraftPlayer {
   }
 
   protected void saveSafe(
-      @NotNull ServerPlayer player,
+      ServerPlayer player,
       @Nullable CompoundTag oldData,
-      @NotNull CompoundTag playerData,
-      @NotNull PlayerDataStorage worldNbtStorage
+      CompoundTag playerData,
+      PlayerDataStorage worldNbtStorage
   ) throws IOException {
     // Revert certain special data values when offline.
     revertSpecialValues(playerData, oldData);
@@ -129,15 +130,15 @@ public class OpenPlayer extends CraftPlayer {
   }
 
   protected void safeReplaceFile(
-      @NotNull Path dataFile,
-      @NotNull Path tempFile,
-      @NotNull Path backupFile
+      Path dataFile,
+      Path tempFile,
+      Path backupFile
   ) {
     net.minecraft.util.Util.safeReplaceFile(dataFile, tempFile, backupFile);
   }
 
   @Contract("null -> new")
-  protected @NotNull CompoundTag getWritableTag(@Nullable CompoundTag oldData) {
+  protected CompoundTag getWritableTag(@Nullable CompoundTag oldData) {
     if (oldData == null) {
       return new CompoundTag();
     }
@@ -155,7 +156,7 @@ public class OpenPlayer extends CraftPlayer {
     return oldData;
   }
 
-  protected void revertSpecialValues(@NotNull CompoundTag newData, @Nullable CompoundTag oldData) {
+  protected void revertSpecialValues(CompoundTag newData, @Nullable CompoundTag oldData) {
     if (oldData == null) {
       return;
     }
@@ -167,11 +168,11 @@ public class OpenPlayer extends CraftPlayer {
   }
 
   private <T extends Tag> void copyValue(
-      @NotNull CompoundTag source,
-      @NotNull CompoundTag target,
-      @NotNull String container,
-      @NotNull String key,
-      @SuppressWarnings("SameParameterValue") @NotNull Class<T> tagType
+      CompoundTag source,
+      CompoundTag target,
+      String container,
+      String key,
+      @SuppressWarnings("SameParameterValue") Class<T> tagType
   ) {
     CompoundTag oldContainer = getTag(source, container, CompoundTag.class);
     CompoundTag newContainer = getTag(target, container, CompoundTag.class);
@@ -187,8 +188,8 @@ public class OpenPlayer extends CraftPlayer {
 
   private <T extends Tag> @Nullable T getTag(
       @Nullable CompoundTag container,
-      @NotNull String key,
-      @NotNull Class<T> dataType
+      String key,
+      Class<T> dataType
   ) {
     if (container == null) {
       return null;
@@ -201,8 +202,8 @@ public class OpenPlayer extends CraftPlayer {
   }
 
   private <T extends Tag> void setTag(
-      @NotNull CompoundTag container,
-      @NotNull String key,
+      CompoundTag container,
+      String key,
       @Nullable T data
   ) {
     if (data == null) {
@@ -212,7 +213,7 @@ public class OpenPlayer extends CraftPlayer {
     }
   }
 
-  protected void remove(@NotNull CompoundTag tag, @NotNull String key) {
+  protected void remove(CompoundTag tag, String key) {
     tag.remove(key);
   }
 

internal/paper26_3/src/main/java/com/lishid/openinv/internal/paper26_3/player/PlayerManager.java

@@ -1,10 +1,11 @@
-package com.lishid.openinv.internal.paper26_2.player;
+package com.lishid.openinv.internal.paper26_3.player;
 
 import com.lishid.openinv.internal.ISpecialInventory;
-import com.lishid.openinv.internal.paper26_2.container.BaseOpenInventory;
-import com.lishid.openinv.internal.paper26_2.container.OpenEnderChest;
-import com.lishid.openinv.internal.paper26_2.container.menu.OpenChestMenu;
-import com.lishid.openinv.util.JulLoggerAdapter;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.lishid.openinv.internal.paper26_3.container.BaseOpenInventory;
+import com.lishid.openinv.internal.paper26_3.container.OpenEnderChest;
+import com.lishid.openinv.internal.paper26_3.container.menu.OpenChestMenu;
+import com.github.jikoo.openinv.util.JulLoggerAdapter;
 import com.mojang.authlib.GameProfile;
 import com.mojang.logging.LogUtils;
 import io.papermc.paper.adventure.PaperAdventure;
@@ -17,9 +18,13 @@ import net.minecraft.server.level.ParticleStatus;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.util.ProblemReporter;
+import net.minecraft.world.Container;
 import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.player.ChatVisiblity;
 import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.storage.LevelData;
 import net.minecraft.world.level.storage.TagValueInput;
@@ -46,13 +51,18 @@ import java.util.UUID;
 import java.util.logging.Logger;
 
 @NullMarked
-public class PlayerManager implements com.lishid.openinv.internal.PlayerManager {
+public class PlayerManager implements com.github.jikoo.openinv.internal.PlayerManager {
 
   protected final Logger logger;
+  protected final InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory;
   protected @Nullable Field bukkitEntity;
 
-  public PlayerManager(Logger logger) {
+  public PlayerManager(
+      Logger logger,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory
+  ) {
     this.logger = logger;
+    this.factory = factory;
     try {
       bukkitEntity = Entity.class.getDeclaredField("bukkitEntity");
     } catch (NoSuchFieldException e) {
@@ -249,8 +259,9 @@ public class PlayerManager implements com.lishid.openinv.internal.PlayerManager
         CompoundTag extraData = new CompoundTag();
 
         // Copy extra data out of existing player.
+        CraftPlayer oldPlayer = nmsPlayer.getBukkitEntity();
         ValueOutput output = TagValueOutput.createWrappingWithContext(scopedCollector, nmsPlayer.registryAccess(), extraData);
-        nmsPlayer.getBukkitEntity().setExtraData(output);
+        oldPlayer.setExtraData(output);
 
         MinecraftServer server = nmsPlayer.level().getServer();
         injectPlayer(server, nmsPlayer);
@@ -259,6 +270,9 @@ public class PlayerManager implements com.lishid.openinv.internal.PlayerManager
         // Set extra data in new player.
         ValueInput input = TagValueInput.create(scopedCollector, nmsPlayer.registryAccess(), extraData);
         newPlayer.readExtraData(input);
+        // The persistent data container belongs to the Bukkit wrapper, not the ServerPlayer.
+        // Without copying it, saving drops all plugin data from the player file
+        newPlayer.getPersistentDataContainer().putAll(oldPlayer.getPersistentDataContainer().toTagCompound());
 
         return newPlayer;
       }
@@ -291,7 +305,7 @@ public class PlayerManager implements com.lishid.openinv.internal.PlayerManager
       menu = playerInv.createMenu(player, player.nextContainerCounter(), viewOnly);
       title = playerInv.getTitle(player, menu);
     } else if (inventory instanceof OpenEnderChest enderChest) {
-      menu = enderChest.createMenu(player, player.nextContainerCounter(), viewOnly);
+      menu = enderChest.createMenu(factory, player, player.nextContainerCounter(), viewOnly);
       title = enderChest.getTitle(menu);
     } else {
       return null;

internal/spigot26_1/build.gradle.kts

@@ -33,4 +33,7 @@ dependencies {
   compileOnly(project(":openinvadapterspigot26_2")) {
     exclude(group = "org.spigotmc", module = "spigot")
   }
+  compileOnly(project(":openinvadapterspigot26_3")) {
+    exclude(group = "org.spigotmc", module = "spigot")
+  }
 }

internal/spigot26_1/src/main/java/com/github/jikoo/openinv/internal/spigot26_1/InternalAccessor.java

@@ -1,8 +1,14 @@
 package com.github.jikoo.openinv.internal.spigot26_1;
 
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
 import com.github.jikoo.openinv.internal.spigot26_1.container.slot.placeholder.PlaceholderLoader;
 import com.github.jikoo.openinv.internal.spigot26_1.player.PlayerManager;
-import com.lishid.openinv.util.lang.LanguageManager;
+import com.github.jikoo.openinv.lang.LanguageManager;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
 import org.bukkit.configuration.ConfigurationSection;
 import org.jspecify.annotations.NullMarked;
 
@@ -12,16 +18,16 @@ import java.util.logging.Logger;
 @NullMarked
 public class InternalAccessor extends com.github.jikoo.openinv.internal.spigot26_2.InternalAccessor {
 
-  private final PlayerManager manager;
-
   public InternalAccessor(Logger logger, LanguageManager lang) {
     super(logger, lang);
-    this.manager = new PlayerManager(logger);
   }
 
   @Override
-  public PlayerManager getPlayerManager() {
-    return manager;
+  protected PlayerManager createPlayerManager(
+      Logger logger,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory
+  ) {
+    return new PlayerManager(logger, factory);
   }
 
   @Override

internal/spigot26_1/src/main/java/com/github/jikoo/openinv/internal/spigot26_1/container/slot/placeholder/PlaceholderLoader.java

@@ -1,6 +1,6 @@
 package com.github.jikoo.openinv.internal.spigot26_1.container.slot.placeholder;
 
-import com.github.jikoo.openinv.internal.spigot26_2.container.slot.placeholder.PlaceholderLoaderBase;
+import com.github.jikoo.openinv.internal.spigot26_3.container.slot.placeholder.PlaceholderLoaderBase;
 import net.minecraft.world.item.Item;
 import net.minecraft.world.item.Items;
 import org.jspecify.annotations.NullMarked;

internal/spigot26_1/src/main/java/com/github/jikoo/openinv/internal/spigot26_1/player/PlayerManager.java

@@ -1,15 +1,24 @@
 package com.github.jikoo.openinv.internal.spigot26_1.player;
 
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
 import net.minecraft.server.PlayerAdvancements;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
 import org.jspecify.annotations.NullMarked;
 
 import java.util.logging.Logger;
 
 @NullMarked
-public class PlayerManager extends com.github.jikoo.openinv.internal.spigot26_2.player.PlayerManager {
+public class PlayerManager extends com.github.jikoo.openinv.internal.spigot26_3.player.PlayerManager {
 
-  public PlayerManager(Logger logger) {
-    super(logger);
+  public PlayerManager(
+      Logger logger,
+      InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> factory
+  ) {
+    super(logger, factory);
   }
 
   @Override

internal/spigot26_2/build.gradle.kts

@@ -22,11 +22,15 @@ apply<SpigotSetup>()
 dependencies {
   compileOnly(libs.spigotapi)
   extensions.getByType(SpigotDependencyExtension::class.java).version = "26.2-R0.1-SNAPSHOT"
-  compileOnly("com.mojang:logging:1.6.11")
+  compileOnly("com.mojang:logging:1.7.12")
   compileOnly("com.mojang:brigadier:1.3.10")
-  compileOnly("com.mojang:datafixerupper:9.0.19")
-  compileOnly("com.mojang:authlib:7.0.62")
+  compileOnly("com.mojang:datafixerupper:10.0.21")
+  compileOnly("com.mojang:authlib:9.0.75")
 
   compileOnly(project(":openinvapi"))
   compileOnly(project(":openinvcommon"))
+
+  compileOnly(project(":openinvadapterspigot26_3")) {
+    exclude(group = "org.spigotmc", module = "spigot")
+  }
 }

internal/spigot26_2/src/main/java/com/github/jikoo/openinv/internal/spigot26_2/InternalAccessor.java

@@ -1,80 +1,27 @@
 package com.github.jikoo.openinv.internal.spigot26_2;
 
-import com.github.jikoo.openinv.internal.spigot26_2.container.AnySilentContainer;
-import com.github.jikoo.openinv.internal.spigot26_2.container.OpenInventory;
-import com.github.jikoo.openinv.internal.spigot26_2.container.OpenEnderChest;
-import com.github.jikoo.openinv.internal.spigot26_2.container.slot.placeholder.PlaceholderLoader;
-import com.github.jikoo.openinv.internal.spigot26_2.player.PlayerManager;
-import com.lishid.openinv.internal.Accessor;
-import com.lishid.openinv.internal.IAnySilentContainer;
-import com.lishid.openinv.internal.ISpecialEnderChest;
-import com.lishid.openinv.internal.ISpecialInventory;
-import com.lishid.openinv.internal.ISpecialPlayerInventory;
-import com.lishid.openinv.util.lang.LanguageManager;
+import com.github.jikoo.openinv.internal.container.slot.InventoryFactory;
+import com.github.jikoo.openinv.internal.spigot26_2.container.slot.OpenInventoryFactory;
+import com.github.jikoo.openinv.lang.LanguageManager;
+import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.Container;
-import org.bukkit.configuration.ConfigurationSection;
-import org.bukkit.craftbukkit.inventory.CraftInventory;
-import org.bukkit.entity.Player;
-import org.bukkit.inventory.Inventory;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jspecify.annotations.NullMarked;
 
-import java.util.logging.Level;
 import java.util.logging.Logger;
 
-public class InternalAccessor implements Accessor {
+@NullMarked
+public class InternalAccessor extends com.github.jikoo.openinv.internal.spigot26_3.InternalAccessor {
 
-  protected final @NotNull Logger logger;
-  private final @NotNull PlayerManager manager;
-  private final @NotNull AnySilentContainer anySilentContainer;
-
-  public InternalAccessor(@NotNull Logger logger, @NotNull LanguageManager lang) {
-    this.logger = logger;
-    manager = new PlayerManager(logger);
-    anySilentContainer = new AnySilentContainer(logger, lang);
+  public InternalAccessor(Logger logger, LanguageManager lang) {
+    super(logger, lang);
   }
 
   @Override
-  public @NotNull PlayerManager getPlayerManager() {
-    return manager;
-  }
-
-  @Override
-  public @NotNull IAnySilentContainer getAnySilentContainer() {
-    return anySilentContainer;
-  }
-
-  @Override
-  public @NotNull ISpecialPlayerInventory createPlayerInventory(@NotNull Player player) {
-    return new OpenInventory(player);
-  }
-
-  @Override
-  public @NotNull ISpecialEnderChest createEnderChest(@NotNull Player player) {
-    return new OpenEnderChest(player);
-  }
-
-  @Override
-  public <T extends ISpecialInventory> @Nullable T get(@NotNull Inventory bukkitInventory, @NotNull Class<T> clazz) {
-    if (!(bukkitInventory instanceof CraftInventory craftInventory)) {
-      return null;
-    }
-    Container container = craftInventory.getInventory();
-    if (clazz.isInstance(container)) {
-      return clazz.cast(container);
-    }
-    return null;
-  }
-
-  @Override
-  public void reload(@NotNull ConfigurationSection config) {
-    ConfigurationSection placeholders = config.getConfigurationSection("placeholders");
-    try {
-      // Reset placeholders to defaults and try to load configuration.
-      new PlaceholderLoader().load(placeholders);
-    } catch (Exception e) {
-      logger.log(Level.WARNING, "Caught exception loading placeholder overrides!", e);
-    }
+  protected InventoryFactory<ServerPlayer, ItemStack, Container, Slot, EquipmentSlot> createInventoryFactory() {
+    return new OpenInventoryFactory();
   }
 
 }

internal/spigot26_2/src/main/java/com/github/jikoo/openinv/internal/spigot26_2/container/bukkit/OpenPlayerInventorySelf.java

@@ -1,26 +0,0 @@
-package com.github.jikoo.openinv.internal.spigot26_2.container.bukkit;
-
-import com.github.jikoo.openinv.internal.spigot26_2.container.OpenInventory;
-import org.bukkit.inventory.ItemStack;
-import org.jetbrains.annotations.NotNull;
-
-public class OpenPlayerInventorySelf extends OpenPlayerInventory {
-
-  private final int offset;
-
-  public OpenPlayerInventorySelf(@NotNull OpenInventory inventory, int offset) {
-    super(inventory);
-    this.offset = offset;
-  }
-
-  @Override
-  public ItemStack getItem(int index) {
-    return super.getItem(offset + index);
-  }
-
-  @Override
-  public void setItem(int index, ItemStack item) {
-    super.setItem(offset + index, item);
-  }
-
-}

internal/spigot26_2/src/main/java/com/github/jikoo/openinv/internal/spigot26_2/container/slot/Content.java

@@ -1,69 +0,0 @@
-package com.github.jikoo.openinv.internal.spigot26_2.container.slot;
-
-import net.minecraft.server.level.ServerPlayer;
-import net.minecraft.world.Container;
-import net.minecraft.world.inventory.Slot;
-import net.minecraft.world.item.ItemStack;
-import org.jetbrains.annotations.NotNull;
-
-/**
- * An interface defining behaviors for entries in a {@link Container}. Used to reduce duplicate content reordering.
- */
-public interface Content {
-
-  /**
-   * Update internal holder.
-   *
-   * @param holder the new holder
-   */
-  void setHolder(@NotNull ServerPlayer holder);
-
-  /**
-   * Get the current item.
-   *
-   * @return the current item
-   */
-  ItemStack get();
-
-  /**
-   * Remove the current item.
-   *
-   * @return the current item
-   */
-  ItemStack remove();
-
-  /**
-   * Remove some of the current item.
-   *
-   * @return the current item
-   */
-  ItemStack removePartial(int amount);
-
-  /**
-   * Set the current item. If slot is currently not usable, will drop item instead.
-   *
-   * @param itemStack the item to set
-   */
-  void set(ItemStack itemStack);
-
-  /**
-   * Get a {@link Slot} for use in a {@link net.minecraft.world.inventory.AbstractContainerMenu ContainerMenu}. Will
-   * impose any specific restrictions to insertion or removal.
-   *
-   * @param container the backing container
-   * @param slot the slot of the backing container represented
-   * @param x clientside x dimension from top left of inventory, not used
-   * @param y clientside y dimension from top left of inventory, not used
-   * @return a menu slot
-   */
-  Slot asSlot(Container container, int slot, int x, int y);
-
-  /**
-   * Get a loose Bukkit translation of what this slot stores. For example, any slot that drops items at the owner rather
-   * than insert them will report itself as being {@link org.bukkit.event.inventory.InventoryType.SlotType#OUTSIDE}.
-   *
-   * @return the closes Bukkit slot type
-   */
-  org.bukkit.event.inventory.InventoryType.SlotType getSlotType();
-
-}