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 c038be43af1af9b077060ae26bb63756de02cdd0..3a1f9598c3e25a061ac934102bd86b8c9c8332a1 100644
--- a/src/main/java/net/minecraft/world/level/Level.java
+++ b/src/main/java/net/minecraft/world/level/Level.java
@@ -1758,7 +1758,7 @@ 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 9d69e439ff853465303c2abd896e6c5314752e1e..8313d0a927b693fb355c9d6bd5284c5a78d5f322 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 9603d8c84ff483030dc08e82d3579b89e5c1f6e9..4148a7fa8ba249d34ba670b015b123c943a225e8 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 c4471342eea4f9e2b0916fc1c5f1b24bc07757fd..32bf3d9b5482a85e23e7f6ad21392a5d16ba3fee 100644
--- a/src/main/java/net/minecraft/world/level/block/RedStoneWireBlock.java
+++ b/src/main/java/net/minecraft/world/level/block/RedStoneWireBlock.java
@@ -199,8 +199,9 @@ 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 67be58de9f684e440b62541365c079cfffe30e51..a6bc5c5053f1fce822166d0cd1ea67dc490dc0af 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++;
             }
@@ -150,7 +152,9 @@ public class CollectingNeighborUpdater implements NeighborUpdater {
         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;
         }
     }
@@ -158,8 +162,8 @@ 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;
         }
     }