Paper/patches/server/0313-Don-t-load-Chunks-from-Hoppers-and-other-things.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Thu, 3 Nov 2016 20:28:12 -0400
Subject: [PATCH] Don't load Chunks from Hoppers and other things

Hoppers call this to I guess "get the primary side" of a double sided chest.

If the double sided chest crosses chunk lines, it causes the chunk to load.
This will end up causing sync chunk loads, which will unload with Chunk GC,
only to be reloaded again the next tick.

This of course is undesirable, so just return the loaded side as "primary"
and treat it as a single chest if the other sides are unloaded

diff --git a/src/main/java/net/minecraft/world/level/block/DoubleBlockCombiner.java b/src/main/java/net/minecraft/world/level/block/DoubleBlockCombiner.java
index 0a40d9b7e394fa10d6bfb0057440e1b0e55d1fc4..c889d2e08b9e7c8ee374f0148e72bb3bc9a1d826 100644
--- a/src/main/java/net/minecraft/world/level/block/DoubleBlockCombiner.java
+++ b/src/main/java/net/minecraft/world/level/block/DoubleBlockCombiner.java
@@ -25,7 +25,12 @@ public class DoubleBlockCombiner {
                 return new DoubleBlockCombiner.NeighborCombineResult.Single<>(blockEntity);
             } else {
                 BlockPos blockPos = pos.relative(directionMapper.apply(state));
-                BlockState blockState = world.getBlockState(blockPos);
+                // Paper start - Don't load Chunks from Hoppers and other things
+                BlockState blockState = world.getBlockStateIfLoaded(blockPos);
+                if (blockState == null) {
+                    return new DoubleBlockCombiner.NeighborCombineResult.Single<>(blockEntity);
+                }
+                // Paper end - Don't load Chunks from Hoppers and other things
                 if (blockState.is(state.getBlock())) {
                     DoubleBlockCombiner.BlockType blockType2 = typeMapper.apply(blockState);
                     if (blockType2 != DoubleBlockCombiner.BlockType.SINGLE && blockType != blockType2 && blockState.getValue(directionProperty) == state.getValue(directionProperty)) {