From 38dc14eca1712f7989bf4aa641d4d3d2b502e9fc Mon Sep 17 00:00:00 2001
From: slprime <31038811+slprime@users.noreply.github.com>
Date: Fri, 11 Sep 2026 08:30:49 +0300
Subject: [PATCH] Fix concurrent modification crash in API.hideItem (#1030)

---
 src/main/java/codechicken/nei/api/API.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/codechicken/nei/api/API.java b/src/main/java/codechicken/nei/api/API.java
index 38113916..dd5af1f1 100644
--- a/src/main/java/codechicken/nei/api/API.java
+++ b/src/main/java/codechicken/nei/api/API.java
@@ -146,14 +146,14 @@ public class API {
      * Hide an item from the item panel Damage values of OreDictionary.WILDCARD_VALUE and ItemStackMap.WILDCARD_TAG tags
      * function as wildcards for their respective variables
      */
-    public static void hideItem(ItemStack item) {
+    public static synchronized void hideItem(ItemStack item) {
         if (!ItemInfo.hiddenItems.contains(item)) {
             ItemInfo.hiddenItems.add(item);
             LayoutManager.markItemsDirty();
         }
     }
 
-    public static void hideItem(String rule) {
+    public static synchronized void hideItem(String rule) {
         ItemFilter filter = ItemStackFilterParser.parse(rule);
         if (filter != null) {
             ItemInfo.hiddenItemsRules.filters.add(filter);