OpenVdra · Alexteens24 · Jul 17, 2026
diff --git a/core/src/main/java/github/nighter/smartspawner/spawner/gui/storage/SpawnerStorageAction.java b/core/src/main/java/github/nighter/smartspawner/spawner/gui/storage/SpawnerStorageAction.java
@@ -43,6 +43,7 @@ public class SpawnerStorageAction implements Listener {
     private final MessageService messageService;
     private final FilterConfigUI filterConfigUI;
     private final SpawnerManager spawnerManager;
+    private final SpawnerStorageUI spawnerStorageUI;
 
     private static final int INVENTORY_SIZE = 54;
     private static final int STORAGE_SLOTS = 45;
@@ -59,6 +60,7 @@ public SpawnerStorageAction(SmartSpawner plugin) {
         this.messageService = plugin.getMessageService();
         this.filterConfigUI = plugin.getFilterConfigUI();
         this.spawnerManager = plugin.getSpawnerManager();
+        this.spawnerStorageUI = plugin.getSpawnerStorageUI();
         loadConfig();
     }
 
@@ -69,8 +71,12 @@ public void loadConfig() {
 
     @EventHandler(priority = EventPriority.LOWEST)
     public void onInventoryClick(InventoryClickEvent event) {
-        if (!(event.getWhoClicked() instanceof Player player) ||
-                !(event.getInventory().getHolder(false) instanceof StoragePageHolder holder)) {
+        if (!(event.getWhoClicked() instanceof Player player)) {
+            return;
+        }
+
+        StoragePageHolder holder = spawnerStorageUI.getStorageHolder(event.getInventory());
+        if (holder == null) {
             return;
         }
 
@@ -252,7 +258,7 @@ private boolean handleCollectExpAction(Player player, SpawnerData spawner, Inven
         boolean collected = plugin.getSpawnerMenuAction().tryCollectExpForPlayer(player, spawner);
         if (collected) {
             // Refresh button display so the XP counter updates to 0
-            StoragePageHolder holder = (StoragePageHolder) inventory.getHolder(false);
+            StoragePageHolder holder = spawnerStorageUI.getStorageHolder(inventory);
             if (holder != null) {
                 plugin.getSpawnerStorageUI().updateDisplay(inventory, spawner, holder.getCurrentPage(), holder.getTotalPages());
             }
@@ -434,7 +440,7 @@ private void updatePageAfterRemoval(Player player, Inventory inventory,
     }
 
     private boolean handleDropPageItems(Player player, SpawnerData spawner, Inventory inventory) {
-        StoragePageHolder holder = (StoragePageHolder) inventory.getHolder(false);
+        StoragePageHolder holder = spawnerStorageUI.getStorageHolder(inventory);
         if (holder == null) {
             return false;
         }
@@ -546,11 +552,13 @@ private void openFilterConfig(Player player, SpawnerData spawner) {
 
     private void updatePageContent(Player player, SpawnerData spawner, int newPage, Inventory inventory) {
         SpawnerStorageUI spawnerStorageUI = plugin.getSpawnerStorageUI();
-        StoragePageHolder holder = (StoragePageHolder) inventory.getHolder(false);
+        StoragePageHolder holder = spawnerStorageUI.getStorageHolder(inventory);
+        if (holder == null) {
+            return;
+        }
 
         int totalPages = calculateTotalPages(spawner);
 
-        assert holder != null;
         holder.setTotalPages(totalPages);
         holder.setCurrentPage(newPage);
         holder.updateOldUsedSlots();
@@ -680,7 +688,7 @@ private boolean handleSortItemsClick(Player player, SpawnerData spawner, Invento
         spawner.getVirtualInventory().sortItems(nextSort);
 
         // Update GUI display to reflect VirtualInventory state
-        StoragePageHolder holder = (StoragePageHolder) inventory.getHolder(false);
+        StoragePageHolder holder = spawnerStorageUI.getStorageHolder(inventory);
         if (holder != null) {
             updatePageContent(player, spawner, holder.getCurrentPage(), inventory);
         }
@@ -719,7 +727,10 @@ private void openLootPage(Player player, SpawnerData spawner, int page) {
     }
 
     public boolean handleTakeAllItems(Player player, Inventory sourceInventory) {
-        StoragePageHolder holder = (StoragePageHolder) sourceInventory.getHolder(false);
+        StoragePageHolder holder = spawnerStorageUI.getStorageHolder(sourceInventory);
+        if (holder == null) {
+            return false;
+        }
         SpawnerData spawner = holder.getSpawnerData();
         VirtualInventory virtualInv = spawner.getVirtualInventory();
 
@@ -745,7 +756,7 @@ public boolean handleTakeAllItems(Player player, Inventory sourceInventory) {
         }
 
         // Transfer items and update VirtualInventory
-        TransferResult result = transferItems(player, sourceInventory, sourceItems, virtualInv);
+        TransferResult result = transferItems(player, sourceInventory, sourceItems, virtualInv, holder);
         sendTransferMessage(player, result);
         player.updateInventory();
 
@@ -803,7 +814,8 @@ private void playActionResult(
     }
 
     private TransferResult transferItems(Player player, Inventory sourceInventory,
-                                         Map<Integer, ItemStack> sourceItems, VirtualInventory virtualInv) {
+                                         Map<Integer, ItemStack> sourceItems, VirtualInventory virtualInv,
+                                         StoragePageHolder holder) {
         boolean anyItemMoved = false;
         boolean inventoryFull = false;
         PlayerInventory playerInv = player.getInventory();
@@ -864,7 +876,6 @@ else if (targetItem.isSimilar(itemToMove)) {
 
         // Update VirtualInventory
         if (!itemsToRemove.isEmpty()) {
-            StoragePageHolder holder = (StoragePageHolder) sourceInventory.getHolder(false);
             SpawnerData spawnerData = holder.getSpawnerData();
 
             spawnerData.removeItemsAndUpdateSellValue(itemsToRemove);
@@ -886,7 +897,7 @@ private void sendTransferMessage(Player player, TransferResult result) {
 
     @EventHandler
     public void onInventoryDrag(InventoryDragEvent event) {
-        if (!(event.getInventory().getHolder(false) instanceof StoragePageHolder)) {
+        if (spawnerStorageUI.getStorageHolder(event.getInventory()) == null) {
             return;
         }
         event.setCancelled(true);
@@ -895,14 +906,11 @@ public void onInventoryDrag(InventoryDragEvent event) {
     @EventHandler
     public void onInventoryClose(InventoryCloseEvent event) {
         Inventory inventory = event.getInventory();
-        if (!(inventory.getHolder(false) instanceof StoragePageHolder holder)) {
+        StoragePageHolder holder = spawnerStorageUI.unregisterStorageInventory(inventory);
+        if (holder == null) {
             return;
         }
 
-        // Inventory close events already execute on the owning player's region thread.
-        // Do not defer this work to the player's scheduler: after closing, a block-backed
-        // inventory could belong to a different region and resolving its holder there
-        // violates Folia's thread ownership rules.
         handleInventoryClose(holder);
     }
 

diff --git a/core/src/main/java/github/nighter/smartspawner/spawner/gui/storage/SpawnerStorageUI.java b/core/src/main/java/github/nighter/smartspawner/spawner/gui/storage/SpawnerStorageUI.java
@@ -38,6 +38,7 @@ public class SpawnerStorageUI {
 
     // Precomputed buttons to avoid repeated creation
     private final Map<String, ItemStack> staticButtons;
+    private final Map<Inventory, StoragePageHolder> storageInventories;
 
     // Lightweight caches with better eviction strategies
     private final Map<String, ItemStack> navigationButtonCache;
@@ -59,6 +60,7 @@ public SpawnerStorageUI(SmartSpawner plugin) {
 
         // Initialize caches with appropriate initial capacity
         this.staticButtons = new ConcurrentHashMap<>(16);
+        this.storageInventories = Collections.synchronizedMap(new IdentityHashMap<>());
         this.navigationButtonCache = new ConcurrentHashMap<>(16);
         this.pageIndicatorCache = new ConcurrentHashMap<>(16);
 
@@ -209,17 +211,38 @@ public Inventory createStorageInventory(Player player, SpawnerData spawner, int
         GuiLayout layout = layoutConfig.getStorageLayout(spawner, player);
 
         // Create inventory with title including page info using placeholder-based format
+        StoragePageHolder holder = new StoragePageHolder(spawner, page, totalPages, layout);
         Inventory pageInv = Bukkit.createInventory(
-                new StoragePageHolder(spawner, page, totalPages, layout),
+                holder,
                 INVENTORY_SIZE,
                 getStorageTitle(spawner, page, totalPages)
         );
+        storageInventories.put(pageInv, holder);
 
-        // Populate the inventory
-        updateDisplay(pageInv, spawner, page, totalPages);
+        // Populate the inventory. If construction fails, do not retain a
+        // registry entry for an inventory that will never be opened.
+        try {
+            updateDisplay(pageInv, spawner, page, totalPages);
+        } catch (RuntimeException | Error failure) {
+            storageInventories.remove(pageInv);
+            throw failure;
+        }
         return pageInv;
     }
 
+    /**
+     * Resolves holders only for virtual storage inventories created by this UI.
+     * This deliberately avoids Inventory#getHolder(), which may access a block
+     * inventory in a region not owned by the current Folia thread.
+     */
+    public StoragePageHolder getStorageHolder(Inventory inventory) {
+        return storageInventories.get(inventory);
+    }
+
+    public StoragePageHolder unregisterStorageInventory(Inventory inventory) {
+        return storageInventories.remove(inventory);
+    }
+
     public void updateDisplay(Inventory inventory, SpawnerData spawner, int page, int totalPages) {
         if (!spawner.getInventoryLock().tryLock()) {
             if (plugin.isDebugMode()) {
@@ -242,8 +265,11 @@ public void updateDisplay(Inventory inventory, SpawnerData spawner, int page, in
         }
 
         // Also mark all button slots for potential clearing (fixes visual bug where buttons remain when they shouldn't)
-        StoragePageHolder holder = (StoragePageHolder) inventory.getHolder(false);
-        assert holder != null;
+        StoragePageHolder holder = getStorageHolder(inventory);
+        if (holder == null) {
+            spawner.getInventoryLock().unlock();
+            return;
+        }
         GuiLayout layout = holder.getLayout();
         if (layout != null) {
             slotsToEmpty.addAll(layout.getUsedSlots());

diff --git a/...n/java/github/nighter/smartspawner/spawner/gui/synchronization/SpawnerGuiViewManager.java b/...n/java/github/nighter/smartspawner/spawner/gui/synchronization/SpawnerGuiViewManager.java
@@ -13,7 +13,6 @@
 import github.nighter.smartspawner.spawner.gui.synchronization.services.TimerUpdateService;
 import github.nighter.smartspawner.spawner.properties.SpawnerData;
 import org.bukkit.Bukkit;
-import org.bukkit.Location;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.Inventory;
 
@@ -204,36 +203,39 @@ public void updateSpawnerMenuViewers(SpawnerData spawner) {
                 continue;
             }
 
-            // Schedule batched GUI update for main menu viewers
-            guiUpdateService.scheduleUpdate(viewerId, GuiUpdateService.UPDATE_ALL);
+            ViewerTrackingManager.ViewerInfo viewerInfo = viewerTrackingManager.getViewerInfo(viewerId);
+            if (viewerInfo == null) {
+                continue;
+            }
 
-            // Handle storage page updates - calculate pages on the correct thread
-            Inventory openInv = viewer.getOpenInventory().getTopInventory();
-            if (openInv.getHolder(false) instanceof StoragePageHolder holder) {
-                // Schedule storage update - page calculation happens inside
-                Location loc = viewer.getLocation();
+            if (viewerInfo.getViewerType() == ViewerTrackingManager.ViewerType.MAIN_MENU) {
+                guiUpdateService.scheduleUpdate(viewerId, GuiUpdateService.UPDATE_ALL);
+                continue;
+            }
+            if (viewerInfo.getViewerType() != ViewerTrackingManager.ViewerType.STORAGE) {
+                continue;
+            }
 
-                if (!holder.getSpawnerData().getSpawnerId().equals(spawner.getSpawnerId())) {
-                    continue;
+            // Entity schedulers follow players across region changes. Resolve the
+            // inventory only after the task owns the player, then use our registry
+            // rather than querying a potentially block-backed inventory holder.
+            Scheduler.runEntityTask(viewer, () -> {
+                if (!viewer.isOnline()) {
+                    return;
                 }
-                Scheduler.runLocationTask(loc, () -> {
-                    if (!viewer.isOnline()) {
-                        return;
-                    }
 
-                    Inventory inv = viewer.getOpenInventory().getTopInventory();
-                    if (inv.getHolder(false) instanceof StoragePageHolder spHolder) {
-
-                        if (!spHolder.getSpawnerData().getSpawnerId().equals(spawner.getSpawnerId())) {
-                            return;
-                        }
-                        int oldPages = storageUpdateService.calculateTotalPages(holder.getOldUsedSlots());
-                        int newPages = storageUpdateService.calculateTotalPages(spawner.getVirtualInventory().getUsedSlots());
+                Inventory inv = viewer.getOpenInventory().getTopInventory();
+                StoragePageHolder holder = plugin.getSpawnerStorageUI().getStorageHolder(inv);
+                if (holder == null ||
+                        !holder.getSpawnerData().getSpawnerId().equals(spawner.getSpawnerId())) {
+                    return;
+                }
 
-                        storageUpdateService.processStorageUpdateDirect(viewer, inv, spawner, spHolder, oldPages, newPages);
-                    }
-                });
-            }
+                int oldPages = storageUpdateService.calculateTotalPages(holder.getOldUsedSlots());
+                int newPages = storageUpdateService.calculateTotalPages(spawner.getVirtualInventory().getUsedSlots());
+                storageUpdateService.processStorageUpdateDirect(
+                        viewer, inv, spawner, holder, oldPages, newPages);
+            });
         }
     }
 

diff --git a/...ithub/nighter/smartspawner/spawner/gui/synchronization/services/StorageUpdateService.java b/...ithub/nighter/smartspawner/spawner/gui/synchronization/services/StorageUpdateService.java
@@ -6,7 +6,6 @@
 import github.nighter.smartspawner.spawner.gui.storage.SpawnerStorageUI;
 import github.nighter.smartspawner.spawner.gui.storage.StoragePageHolder;
 import github.nighter.smartspawner.spawner.properties.SpawnerData;
-import org.bukkit.Location;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.Inventory;
 
@@ -58,22 +57,19 @@ public void reloadCache() {
      * @param newTotalPages New total pages
      */
     public void processStorageUpdate(Player viewer, SpawnerData spawner, int oldTotalPages, int newTotalPages) {
-        Location loc = viewer.getLocation();
-        if (loc != null) {
-            Scheduler.runLocationTask(loc, () -> {
-                if (!viewer.isOnline()) {
-                    return;
-                }
-
-                Inventory openInv = viewer.getOpenInventory().getTopInventory();
-                if (openInv == null || !(openInv.getHolder(false) instanceof StoragePageHolder)) {
-                    return;
-                }
-
-                StoragePageHolder holder = (StoragePageHolder) openInv.getHolder(false);
-                processStorageUpdateDirect(viewer, openInv, spawner, holder, oldTotalPages, newTotalPages);
-            });
-        }
+        Scheduler.runEntityTask(viewer, () -> {
+            if (!viewer.isOnline()) {
+                return;
+            }
+
+            Inventory openInv = viewer.getOpenInventory().getTopInventory();
+            StoragePageHolder holder = spawnerStorageUI.getStorageHolder(openInv);
+            if (holder == null) {
+                return;
+            }
+
+            processStorageUpdateDirect(viewer, openInv, spawner, holder, oldTotalPages, newTotalPages);
+        });
     }
 
     /**