From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sun, 23 Apr 2023 07:08:26 -0700
Subject: [PATCH] Block reading in-world tile entities on worldgen threads

The returned TE may be in the world, in which case it is unsafe
for the current thread to modify or access its contents.

diff --git a/src/main/java/net/minecraft/world/level/chunk/ImposterProtoChunk.java b/src/main/java/net/minecraft/world/level/chunk/ImposterProtoChunk.java
index 6359d2d80f4c1360f8450bf6555ccfea3b69daa5..0d5797cbc0c054d64e54accbe3285854752be267 100644
--- a/src/main/java/net/minecraft/world/level/chunk/ImposterProtoChunk.java
+++ b/src/main/java/net/minecraft/world/level/chunk/ImposterProtoChunk.java
@@ -92,6 +92,11 @@ public class ImposterProtoChunk extends ProtoChunk {
     @Nullable
     @Override
     public BlockEntity getBlockEntity(BlockPos pos) {
+        // Folia start - block reading possibly in-world block data for worldgen threads
+        if (!this.allowWrites && !io.papermc.paper.util.TickThread.isTickThread()) {
+            return null;
+        }
+        // Folia end - block reading possibly in-world block data for worldgen threads
         return this.wrapped.getBlockEntity(pos);
     }