Folia/patches/server/0016-Do-not-access-POI-data-for-lodestone-compass.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sat, 13 May 2023 17:13:40 -0700
Subject: [PATCH] Do not access POI data for lodestone compass

Instead, we can just check the loaded chunk's block position for
the lodestone block, as that is at least safe enough for the light
engine compared to the POI access. This should make it safe for
off-region access.

diff --git a/src/main/java/net/minecraft/world/item/CompassItem.java b/src/main/java/net/minecraft/world/item/CompassItem.java
index 7c4a2f8bb3efd11db2f8711952cc26a067c6d56b..2a60db30bc113039c03ff10b45d5a704a4106b48 100644
--- a/src/main/java/net/minecraft/world/item/CompassItem.java
+++ b/src/main/java/net/minecraft/world/item/CompassItem.java
@@ -77,7 +77,11 @@ public class CompassItem extends Item implements Vanishable {
                 Optional<ResourceKey<Level>> optional = getLodestoneDimension(compoundTag);
                 if (optional.isPresent() && optional.get() == world.dimension() && compoundTag.contains("LodestonePos")) {
                     BlockPos blockPos = NbtUtils.readBlockPos(compoundTag.getCompound("LodestonePos"));
-                    if (!world.isInWorldBounds(blockPos) || (world.hasChunkAt(blockPos) && !((ServerLevel)world).getPoiManager().existsAtPosition(PoiTypes.LODESTONE, blockPos))) { // Paper
+
+                    // Folia start - do not access the POI data off-region
+                    net.minecraft.world.level.chunk.LevelChunk chunk = world.getChunkIfLoaded(blockPos);
+                    if (!world.isInWorldBounds(blockPos) || chunk != null && chunk.getBlockState(blockPos).getBlock() != Blocks.LODESTONE) { // Paper
+                        // Folia end - do not access the POI data off-region
                         compoundTag.remove("LodestonePos");
                     }
                 }