Paper/patches/server/0409-Fix-Entity-Teleportation-and-cancel-velocity-if-tele.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Tue, 25 Aug 2020 20:45:36 -0400
Subject: [PATCH] Fix Entity Teleportation and cancel velocity if teleported

Uses correct setPositionRotation for Entity teleporting instead of setLocation
as this is how Vanilla teleports entities.

Cancel any pending motion when teleported.

diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
index f0e60add7df4d00ee5b84164a532b75f9d90cfa8..a7b270c0ba76f25876c4bb7bda60e61a670d15d9 100644
--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
@@ -679,7 +679,7 @@ public class ServerGamePacketListenerImpl extends ServerCommonPacketListenerImpl
                 return;
             }
 
-            this.player.absMoveTo(this.awaitingPositionFromClient.x, this.awaitingPositionFromClient.y, this.awaitingPositionFromClient.z, this.player.getYRot(), this.player.getXRot());
+            this.player.moveTo(this.awaitingPositionFromClient.x, this.awaitingPositionFromClient.y, this.awaitingPositionFromClient.z, this.player.getYRot(), this.player.getXRot()); // Paper - Fix Entity Teleportation and cancel velocity if teleported
             this.lastGoodX = this.awaitingPositionFromClient.x;
             this.lastGoodY = this.awaitingPositionFromClient.y;
             this.lastGoodZ = this.awaitingPositionFromClient.z;
@@ -1594,7 +1594,7 @@ public class ServerGamePacketListenerImpl extends ServerCommonPacketListenerImpl
         // CraftBukkit end
 
         this.awaitingTeleportTime = this.tickCount;
-        this.player.absMoveTo(d0, d1, d2, f, f1);
+        this.player.moveTo(d0, d1, d2, f, f1); // Paper - Fix Entity Teleportation and cancel velocity if teleported
         this.player.connection.send(new ClientboundPlayerPositionPacket(d0 - d3, d1 - d4, d2 - d5, f - f2, f1 - f3, set, this.awaitingTeleport));
     }
 
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 284d0f88968d386559be94d1e1e7af361658da3f..8a1014d7181b493a24692271aa9c561c159801d3 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -171,6 +171,7 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
 
     // CraftBukkit start
     private static final int CURRENT_LEVEL = 2;
+    public boolean preserveMotion = true; // Paper - Fix Entity Teleportation and cancel velocity if teleported; keep initial motion on first setPositionRotation
     static boolean isLevelAtLeast(CompoundTag tag, int level) {
         return tag.contains("Bukkit.updateLevel") && tag.getInt("Bukkit.updateLevel") >= level;
     }
@@ -1873,6 +1874,13 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
     }
 
     public void moveTo(double x, double y, double z, float yaw, float pitch) {
+        // Paper start - Fix Entity Teleportation and cancel velocity if teleported
+        if (!preserveMotion) {
+            this.deltaMovement = Vec3.ZERO;
+        } else {
+            this.preserveMotion = false;
+        }
+        // Paper end - Fix Entity Teleportation and cancel velocity if teleported
         this.setPosRaw(x, y, z);
         this.setYRot(yaw);
         this.setXRot(pitch);
diff --git a/src/main/java/net/minecraft/world/entity/boss/enderdragon/phases/DragonStrafePlayerPhase.java b/src/main/java/net/minecraft/world/entity/boss/enderdragon/phases/DragonStrafePlayerPhase.java
index a28e6b6a50cfd9191732ad2e4aca5f639a1fae75..244e328c6f67cfa543ee283715bb3b89dbaa0f0c 100644
--- a/src/main/java/net/minecraft/world/entity/boss/enderdragon/phases/DragonStrafePlayerPhase.java
+++ b/src/main/java/net/minecraft/world/entity/boss/enderdragon/phases/DragonStrafePlayerPhase.java
@@ -78,6 +78,7 @@ public class DragonStrafePlayerPhase extends AbstractDragonPhaseInstance {
                         }
 
                         DragonFireball dragonFireball = new DragonFireball(this.dragon.level(), this.dragon, vec34.normalize());
+                        dragonFireball.preserveMotion = true; // Paper - Fix Entity Teleportation and cancel velocity if teleported
                         dragonFireball.moveTo(o, p, q, 0.0F, 0.0F);
                         if (new com.destroystokyo.paper.event.entity.EnderDragonShootFireballEvent((org.bukkit.entity.EnderDragon) dragon.getBukkitEntity(), (org.bukkit.entity.DragonFireball) dragonFireball.getBukkitEntity()).callEvent()) // Paper - EnderDragon Events
                         this.dragon.level().addFreshEntity(dragonFireball);
diff --git a/src/main/java/net/minecraft/world/level/BaseSpawner.java b/src/main/java/net/minecraft/world/level/BaseSpawner.java
index b90127f9f805fdb5bb43a4b8ad2b10499b0b6b78..8efc06d29c62fa2be8515ed3359d52a6d4b807d2 100644
--- a/src/main/java/net/minecraft/world/level/BaseSpawner.java
+++ b/src/main/java/net/minecraft/world/level/BaseSpawner.java
@@ -164,6 +164,7 @@ public abstract class BaseSpawner {
                             return;
                         }
 
+                        entity.preserveMotion = true; // Paper - Fix Entity Teleportation and cancel velocity if teleported; preserve entity motion from tag
                         entity.moveTo(entity.getX(), entity.getY(), entity.getZ(), randomsource.nextFloat() * 360.0F, 0.0F);
                         if (entity instanceof Mob) {
                             Mob entityinsentient = (Mob) entity;
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
index 34321f095e12ea0cca34ff1ec00819c6350205a8..5f5788a502642463091fb76e98703aaec7a86836 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
@@ -240,7 +240,7 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
         }
 
         // entity.setLocation() throws no event, and so cannot be cancelled
-        this.entity.absMoveTo(location.getX(), location.getY(), location.getZ(), location.getYaw(), location.getPitch());
+        entity.moveTo(location.getX(), location.getY(), location.getZ(), location.getYaw(), location.getPitch()); // Paper - use proper moveTo, as per vanilla teleporting
         // SPIGOT-619: Force sync head rotation also
         this.entity.setYHeadRot(location.getYaw());
 
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
index 344ef786330d1247fdfb56ef04be130c9ffb7d8f..af5aab1755f80222a249b1cc7da595af78dccbbd 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
@@ -590,6 +590,7 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {
             }
 
             ((AbstractHurtingProjectile) launch).projectileSource = this;
+            launch.preserveMotion = true; // Paper - Fix Entity Teleportation and cancel velocity if teleported
             launch.moveTo(location.getX(), location.getY(), location.getZ(), location.getYaw(), location.getPitch());
         } else if (LlamaSpit.class.isAssignableFrom(projectile)) {
             Location location = this.getEyeLocation();