From 89a09f326e5e0b18db40b594a4a0beff1f5c9fb6 Mon Sep 17 00:00:00 2001
From: Konstantin Shandurenko <iam@kostya.sexy>
Date: Sat, 30 Jul 2022 19:54:10 +0300
Subject: [PATCH] Fix for inventory window id generation (#1292)

---
 .../java/net/minestom/server/inventory/Inventory.java     | 6 +++++-
 .../java/net/minestom/server/inventory/InventoryTest.java | 8 ++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/main/java/net/minestom/server/inventory/Inventory.java b/src/main/java/net/minestom/server/inventory/Inventory.java
index 1a0df8c04..9bfa8617d 100644
--- a/src/main/java/net/minestom/server/inventory/Inventory.java
+++ b/src/main/java/net/minestom/server/inventory/Inventory.java
@@ -58,7 +58,11 @@ public non-sealed class Inventory extends AbstractInventory implements Viewable
     }
 
     private static byte generateId() {
-        return (byte) Math.abs((byte) ID_COUNTER.incrementAndGet());
+        final byte id = (byte) Math.abs((byte) ID_COUNTER.incrementAndGet());
+        if (id == 0) { // zero is player's inventory id
+            return generateId();
+        }
+        return id;
     }
 
     /**
diff --git a/src/test/java/net/minestom/server/inventory/InventoryTest.java b/src/test/java/net/minestom/server/inventory/InventoryTest.java
index fa3f976bc..f8cb90317 100644
--- a/src/test/java/net/minestom/server/inventory/InventoryTest.java
+++ b/src/test/java/net/minestom/server/inventory/InventoryTest.java
@@ -75,4 +75,12 @@ public class InventoryTest {
         assertTrue(inventory.addItemStack(ItemStack.of(Material.ANDESITE, 32), TransactionOption.ALL_OR_NOTHING));
         assertFalse(inventory.addItemStack(ItemStack.of(Material.BLUE_CONCRETE, 32), TransactionOption.ALL_OR_NOTHING));
     }
+
+    @Test
+    public void testIds() {
+        for (int i = 0; i <= 256; ++i) {
+            final Inventory inventory = new Inventory(InventoryType.CHEST_1_ROW, "title");
+            assertTrue(inventory.getWindowId() != 0);
+        }
+    }
 }