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 706af1c9ec5c115e727753bf75d1fda01accaeca..06e8a82d2001e2a8dd381f3be20ee7442e1d1178 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -663,7 +663,11 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
     }
 
     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
             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 02e3322ec41108fe9275510e2daa833d180353dc..0762bb248b3bd43a06e89aa1893a6189f0e13866 100644
--- a/src/main/java/net/minecraft/world/level/portal/PortalForcer.java
+++ b/src/main/java/net/minecraft/world/level/portal/PortalForcer.java
@@ -55,7 +55,7 @@ public class PortalForcer {
         Optional<PoiRecord> optional = villageplace.getInSquare((holder) -> {
             return holder.is(PoiTypes.NETHER_PORTAL);
         }, blockposition, i, PoiManager.Occupancy.ANY).filter((villageplacerecord) -> {
-            return worldborder.isWithinBounds(villageplacerecord.getPos());
+            return worldborder.isWithinBounds(villageplacerecord.getPos()) && !(this.level.getTypeKey() == net.minecraft.world.level.dimension.LevelStem.NETHER && this.level.paperConfig().environment.netherCeilingVoidDamageHeight.test(v -> villageplacerecord.getPos().getY() >= v)); // Paper - don't teleport into void damage
         }).sorted(Comparator.comparingDouble((PoiRecord villageplacerecord) -> { // CraftBukkit - decompile error
             return villageplacerecord.getPos().distSqr(blockposition);
         }).thenComparingInt((villageplacerecord) -> {
@@ -90,6 +90,11 @@ 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 - if ceiling void damage is enabled, 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
         BlockPos.MutableBlockPos blockposition_mutableblockposition = blockposition.mutable();
         Iterator iterator = BlockPos.spiralAround(blockposition, createRadius, Direction.EAST, Direction.SOUTH).iterator(); // CraftBukkit