From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sat, 1 Apr 2023 00:34:29 -0700
Subject: [PATCH] Acquire scheduling lock in
 NewChunkHolder#onFullChunkLoadChange

It modifies data that should be held by the lock: pending
chunk status

diff --git a/src/main/java/io/papermc/paper/chunk/system/scheduling/NewChunkHolder.java b/src/main/java/io/papermc/paper/chunk/system/scheduling/NewChunkHolder.java
index 3b70ccd8e0b1ada943f57faf99c23b2935249cf6..12feb739a784a0108256451a37d94d041b7a5cdc 100644
--- a/src/main/java/io/papermc/paper/chunk/system/scheduling/NewChunkHolder.java
+++ b/src/main/java/io/papermc/paper/chunk/system/scheduling/NewChunkHolder.java
@@ -1203,8 +1203,12 @@ public final class NewChunkHolder {
         }
     }
 
-    // only call on main thread, must hold ticket level and scheduling lock
+    // only call on main thread // Folia - update comment
     private void onFullChunkLoadChange(final boolean loaded, final List<NewChunkHolder> changedFullStatus) {
+        // Folia start - chunk system fix - acquire scheduling lock
+        this.scheduler.schedulingLock.lock();
+        try {
+        // Folia end - chunk system fix - acquire scheduling lock
         for (int dz = -NEIGHBOUR_RADIUS; dz <= NEIGHBOUR_RADIUS; ++dz) {
             for (int dx = -NEIGHBOUR_RADIUS; dx <= NEIGHBOUR_RADIUS; ++dx) {
                 final NewChunkHolder holder = (dx | dz) == 0 ? this : this.scheduler.chunkHolderManager.getChunkHolder(dx + this.chunkX, dz + this.chunkZ);
@@ -1219,6 +1223,11 @@ public final class NewChunkHolder {
                 }
             }
         }
+        // Folia start - chunk system fix - acquire scheduling lock
+        } finally {
+            this.scheduler.schedulingLock.unlock();
+        }
+        // Folia end - chunk system fix - acquire scheduling lock
     }
 
     private ChunkHolder.FullChunkStatus updateCurrentState(final ChunkHolder.FullChunkStatus to) {