From fcff84de917329dcc53f25e0b63b209dc8032afd Mon Sep 17 00:00:00 2001
From: DerFrZocker <derrieple@gmail.com>
Date: Sat, 17 Jun 2023 11:41:38 +0200
Subject: [PATCH] SPIGOT-7399: Revert null check in CraftMetaItem#safelyAdd

---
 .../org/bukkit/craftbukkit/inventory/CraftMetaItem.java    | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java
index a584c1a03..bf5fb7516 100644
--- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java
+++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java
@@ -1329,7 +1329,12 @@ class CraftMetaItem implements ItemMeta, Damageable, Repairable, BlockDataMeta {
 
         for (Object object : addFrom) {
             if (!(object instanceof String)) {
-                Preconditions.checkArgument(object == null, "%s cannot contain non-string %s", addFrom, object.getClass().getName());
+                if (object != null) {
+                    // SPIGOT-7399: Null check via if is important,
+                    // otherwise object.getClass().getName() could throw an error for a valid argument -> when it is null which is valid,
+                    // when using Preconditions
+                    throw new IllegalArgumentException(addFrom + " cannot contain non-string " + object.getClass().getName());
+                }
 
                 addTo.add(CraftChatMessage.toJSON(IChatBaseComponent.empty()));
             } else {