From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Zach Brown <zach.brown@destroystokyo.com>
Date: Tue, 1 Mar 2016 23:58:50 -0600
Subject: [PATCH] Configurable top of nether void damage

Co-authored-by: Jake Potrebic <jake.m.potrebic@gmail.com>

diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index dbe5239b1a1769ef9f2ef66c32b1a68cd684428e..d5f5864b7c1ad4c30f37b360b317b63c129e3a3f 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -706,7 +706,11 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
     }
 
     public void checkBelowWorld() {
-        if (this.getY() < (double) (this.level().getMinBuildHeight() - 64)) {
+        // Paper start - Configurable nether ceiling damage
+        if (this.getY() < (double) (this.level.getMinBuildHeight() - 64) || (this.level.getWorld().getEnvironment() == org.bukkit.World.Environment.NETHER
+            && this.level.paperConfig().environment.netherCeilingVoidDamageHeight.test(v -> this.getY() >= v)
+            && (!(this instanceof Player player) || !player.getAbilities().invulnerable))) {
+            // Paper end - Configurable nether ceiling damage
             this.onBelowWorld();
         }
 
diff --git a/src/main/java/net/minecraft/world/level/portal/PortalForcer.java b/src/main/java/net/minecraft/world/level/portal/PortalForcer.java
index 46448259cd60ea5e2e08fb58cd2b2b7f8a4ec3cc..aef1dd28da7e0c0a13a0a7a5b52daa27635c48ea 100644
--- a/src/main/java/net/minecraft/world/level/portal/PortalForcer.java
+++ b/src/main/java/net/minecraft/world/level/portal/PortalForcer.java
@@ -58,7 +58,7 @@ public class PortalForcer {
         }, blockposition, i, PoiManager.Occupancy.ANY).map(PoiRecord::getPos);
 
         Objects.requireNonNull(worldborder);
-        return stream.filter(worldborder::isWithinBounds).filter((blockposition1) -> {
+        return stream.filter(worldborder::isWithinBounds).filter(pos -> !(this.level.getTypeKey() == net.minecraft.world.level.dimension.LevelStem.NETHER && this.level.paperConfig().environment.netherCeilingVoidDamageHeight.test(v -> pos.getY() >= v))).filter((blockposition1) -> { // Paper - Configurable nether ceiling damage
             return this.level.getBlockState(blockposition1).hasProperty(BlockStateProperties.HORIZONTAL_AXIS);
         }).min(Comparator.comparingDouble((BlockPos blockposition1) -> { // CraftBukkit - decompile error
             return blockposition1.distSqr(blockposition);
@@ -79,6 +79,11 @@ public class PortalForcer {
         BlockPos blockposition2 = null;
         WorldBorder worldborder = this.level.getWorldBorder();
         int i = Math.min(this.level.getMaxBuildHeight(), this.level.getMinBuildHeight() + this.level.getLogicalHeight()) - 1;
+        // Paper start - Configurable nether ceiling damage; make sure the max height doesn't exceed the void damage height
+        if (this.level.getTypeKey() == net.minecraft.world.level.dimension.LevelStem.NETHER && this.level.paperConfig().environment.netherCeilingVoidDamageHeight.enabled()) {
+            i = Math.min(i, this.level.paperConfig().environment.netherCeilingVoidDamageHeight.intValue() - 1);
+        }
+        // Paper end - Configurable nether ceiling damage
         boolean flag = true;
         BlockPos.MutableBlockPos blockposition_mutableblockposition = blockposition.mutable();
         Iterator iterator = BlockPos.spiralAround(blockposition, createRadius, Direction.EAST, Direction.SOUTH).iterator(); // CraftBukkit