From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jason Penilla <11360596+jpenilla@users.noreply.github.com>
Date: Tue, 31 Aug 2021 17:12:01 -0700
Subject: [PATCH] Use updatingChunks for saving


diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
index d9f1601c49e7e7fc06a6f9bf0cb13aacd66f190c..730d569bd657049c8165d931ac62bf21c65a3b29 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -950,9 +950,18 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
     }
     // Paper end
 
+    // Paper start
+    public Long2ObjectLinkedOpenHashMap<ChunkHolder> getVisibleChunks() {
+        synchronized (this.updatingChunks) {
+            return this.updatingChunks.getVisibleMap().clone();
+        }
+    }
+    // Paper end
+
     protected void saveAllChunks(boolean flush) {
+        final Long2ObjectLinkedOpenHashMap<ChunkHolder> visibleChunks = this.getVisibleChunks(); // Paper
         if (flush) {
-            List<ChunkHolder> list = (List) this.visibleChunkMap.values().stream().filter(ChunkHolder::wasAccessibleSinceLastSave).peek(ChunkHolder::refreshAccessibility).collect(Collectors.toList());
+            List<ChunkHolder> list = visibleChunks.values().stream().filter(ChunkHolder::wasAccessibleSinceLastSave).peek(ChunkHolder::refreshAccessibility).collect(Collectors.toList()); // Paper
             MutableBoolean mutableboolean = new MutableBoolean();
 
             do {
@@ -983,7 +992,7 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
             this.level.asyncChunkTaskManager.flush(); // Paper - flush to preserve behavior compat with pre-async behaviour
 //            this.i(); // Paper - nuke IOWorker
         } else {
-            this.visibleChunkMap.values().stream().filter(ChunkHolder::wasAccessibleSinceLastSave).forEach((playerchunk) -> {
+            visibleChunks.values().stream().filter(ChunkHolder::wasAccessibleSinceLastSave).forEach((playerchunk) -> { // Paper
                 ChunkAccess ichunkaccess = (ChunkAccess) playerchunk.getChunkToSave().getNow(null); // CraftBukkit - decompile error
 
                 if (ichunkaccess instanceof ImposterProtoChunk || ichunkaccess instanceof LevelChunk) {