Folia/patches/server/0011-Prevent-block-updates-in-non-loaded-or-non-owned-chu.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Mon, 17 Apr 2023 19:47:57 -0700
Subject: [PATCH] Prevent block updates in non-loaded or non-owned chunks

This is to prevent block physics from tripping thread checks by
far exceeding the bounds of the current region. While this does
add explicit block update suppression techniques, it's better
than the server crashing.

diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
index 52a7775e7aa375a043438d23204acd030ad35372..55f4fc731b5bde0bbac681a0902af1506ad87762 100644
--- a/src/main/java/net/minecraft/world/level/Level.java
+++ b/src/main/java/net/minecraft/world/level/Level.java
@@ -1762,7 +1762,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
             Direction enumdirection = (Direction) iterator.next();
             BlockPos blockposition1 = pos.relative(enumdirection);
 
-            if (this.hasChunkAt(blockposition1)) {
+            if (io.papermc.paper.util.TickThread.isTickThreadFor((ServerLevel)this, blockposition1) && this.hasChunkAt(blockposition1)) { // Folia - block updates in unloaded chunks
                 BlockState iblockdata = this.getBlockState(blockposition1);
 
                 if (iblockdata.is(Blocks.COMPARATOR)) {
diff --git a/src/main/java/net/minecraft/world/level/block/DetectorRailBlock.java b/src/main/java/net/minecraft/world/level/block/DetectorRailBlock.java
index 57e542d5c8b887acecedf76c08c8d4379d712c0f..9c0ad01eae1e0d5044669f561587a69b6ca8e237 100644
--- a/src/main/java/net/minecraft/world/level/block/DetectorRailBlock.java
+++ b/src/main/java/net/minecraft/world/level/block/DetectorRailBlock.java
@@ -134,9 +134,9 @@ public class DetectorRailBlock extends BaseRailBlock {
 
         while (iterator.hasNext()) {
             BlockPos blockposition1 = (BlockPos) iterator.next();
-            BlockState iblockdata1 = world.getBlockState(blockposition1);
+            BlockState iblockdata1 = !io.papermc.paper.util.TickThread.isTickThreadFor((ServerLevel)world, blockposition1) ? null : world.getBlockStateIfLoaded(blockposition1); // Folia - block updates in unloaded chunks
 
-            world.neighborChanged(iblockdata1, blockposition1, iblockdata1.getBlock(), pos, false);
+            if (iblockdata1 != null) world.neighborChanged(iblockdata1, blockposition1, iblockdata1.getBlock(), pos, false); // Folia - block updates in unloaded chunks
         }
 
     }
diff --git a/src/main/java/net/minecraft/world/level/block/PoweredRailBlock.java b/src/main/java/net/minecraft/world/level/block/PoweredRailBlock.java
index b84c48902ef24fdae17578a304e6c93dc20c5dce..218c1954a7922c9e6bf6f34f9497f89ce1207eac 100644
--- a/src/main/java/net/minecraft/world/level/block/PoweredRailBlock.java
+++ b/src/main/java/net/minecraft/world/level/block/PoweredRailBlock.java
@@ -104,9 +104,9 @@ public class PoweredRailBlock extends BaseRailBlock {
     }
 
     protected boolean isSameRailWithPower(Level world, BlockPos pos, boolean flag, int distance, RailShape shape) {
-        BlockState iblockdata = world.getBlockState(pos);
+        BlockState iblockdata = !io.papermc.paper.util.TickThread.isTickThreadFor((net.minecraft.server.level.ServerLevel)world, pos) ? null : world.getBlockStateIfLoaded(pos); // Folia - block updates in unloaded chunks
 
-        if (!iblockdata.is((Block) this)) {
+        if (iblockdata == null || !iblockdata.is((Block) this)) { // Folia - block updates in unloaded chunks
             return false;
         } else {
             RailShape blockpropertytrackposition1 = (RailShape) iblockdata.getValue(PoweredRailBlock.SHAPE);
diff --git a/src/main/java/net/minecraft/world/level/block/RedStoneWireBlock.java b/src/main/java/net/minecraft/world/level/block/RedStoneWireBlock.java
index 7f33db05284a957690eac6eb6f5b3b05586727bb..cdf9434635e6d3d15e003f1f6e6a3be7df3f5b04 100644
--- a/src/main/java/net/minecraft/world/level/block/RedStoneWireBlock.java
+++ b/src/main/java/net/minecraft/world/level/block/RedStoneWireBlock.java
@@ -200,8 +200,9 @@ public class RedStoneWireBlock extends Block {
         while (iterator.hasNext()) {
             Direction enumdirection = (Direction) iterator.next();
             RedstoneSide blockpropertyredstoneside = (RedstoneSide) state.getValue((Property) RedStoneWireBlock.PROPERTY_BY_DIRECTION.get(enumdirection));
+            BlockState currState; blockposition_mutableblockposition.setWithOffset(pos, enumdirection); // Folia - block updates in unloaded chunks
 
-            if (blockpropertyredstoneside != RedstoneSide.NONE && !world.getBlockState(blockposition_mutableblockposition.setWithOffset(pos, enumdirection)).is((Block) this)) {
+            if (blockpropertyredstoneside != RedstoneSide.NONE && (currState = (world instanceof net.minecraft.server.level.ServerLevel serverLevel && !io.papermc.paper.util.TickThread.isTickThreadFor(serverLevel, pos) ? null : world.getBlockStateIfLoaded(blockposition_mutableblockposition))) != null && !currState.is((Block) this)) { // Folia - block updates in unloaded chunks
                 blockposition_mutableblockposition.move(Direction.DOWN);
                 BlockState iblockdata1 = world.getBlockState(blockposition_mutableblockposition);
 
diff --git a/src/main/java/net/minecraft/world/level/redstone/CollectingNeighborUpdater.java b/src/main/java/net/minecraft/world/level/redstone/CollectingNeighborUpdater.java
index de048d920452b04922871eaaafacd1abd0ee21b7..7c3688849eaad93085cd3510a5a62823a19d649f 100644
--- a/src/main/java/net/minecraft/world/level/redstone/CollectingNeighborUpdater.java
+++ b/src/main/java/net/minecraft/world/level/redstone/CollectingNeighborUpdater.java
@@ -119,7 +119,8 @@ public class CollectingNeighborUpdater implements NeighborUpdater {
         @Override
         public boolean runNext(Level world) {
             BlockPos blockPos = this.sourcePos.relative(NeighborUpdater.UPDATE_ORDER[this.idx++]);
-            BlockState blockState = world.getBlockState(blockPos);
+            BlockState blockState = !io.papermc.paper.util.TickThread.isTickThreadFor((net.minecraft.server.level.ServerLevel)world, blockPos) ? null : world.getBlockStateIfLoaded(blockPos); // Folia - block updates in unloaded chunks
+            if (blockState != null) { // Folia - block updates in unloaded chunks
             // Paper start - Call BlockPhysicsEvent
             try {
                 org.bukkit.event.block.BlockPhysicsEvent event = new org.bukkit.event.block.BlockPhysicsEvent(
@@ -134,6 +135,7 @@ public class CollectingNeighborUpdater implements NeighborUpdater {
                 world.lastPhysicsProblem = blockPos;
             }
             // Paper end - Call BlockPhysicsEvent
+            } // Folia - block updates in unloaded chunks
             if (this.idx < NeighborUpdater.UPDATE_ORDER.length && NeighborUpdater.UPDATE_ORDER[this.idx] == this.skipDirection) {
                 ++this.idx;
             }
@@ -149,7 +151,9 @@ public class CollectingNeighborUpdater implements NeighborUpdater {
     static record ShapeUpdate(Direction direction, BlockState state, BlockPos pos, BlockPos neighborPos, int updateFlags, int updateLimit) implements CollectingNeighborUpdater.NeighborUpdates {
         @Override
         public boolean runNext(Level world) {
+            if (io.papermc.paper.util.TickThread.isTickThreadFor((net.minecraft.server.level.ServerLevel)world, this.pos) && world.getChunkIfLoaded(this.pos) != null) { // Folia - block updates in unloaded chunks
             NeighborUpdater.executeShapeUpdate(world, this.direction, this.state, this.pos, this.neighborPos, this.updateFlags, this.updateLimit);
+            } // Folia - block updates in unloaded chunks
             return false;
         }
     }
@@ -157,8 +161,8 @@ public class CollectingNeighborUpdater implements NeighborUpdater {
     static record SimpleNeighborUpdate(BlockPos pos, Block block, BlockPos neighborPos) implements CollectingNeighborUpdater.NeighborUpdates {
         @Override
         public boolean runNext(Level world) {
-            BlockState blockState = world.getBlockState(this.pos);
-            NeighborUpdater.executeUpdate(world, blockState, this.pos, this.block, this.neighborPos, false);
+            BlockState blockState = !io.papermc.paper.util.TickThread.isTickThreadFor((net.minecraft.server.level.ServerLevel)world, this.pos) ? null : world.getBlockStateIfLoaded(this.pos); // Folia - block updates in unloaded chunks
+            if (blockState != null) NeighborUpdater.executeUpdate(world, blockState, this.pos, this.block, this.neighborPos, false); // Folia - block updates in unloaded chunks
             return false;
         }
     }