Paper/patches/server/0269-force-entity-dismount-during-teleportation.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Shane Freeder <theboyetronic@gmail.com>
Date: Thu, 15 Nov 2018 13:38:37 +0000
Subject: [PATCH] force entity dismount during teleportation

Entities must be dismounted before teleportation in order to avoid
multiple issues in the server with regards to teleportation, shamefully,
too many plugins rely on the events firing, which means that not firing
these events caues more issues than it solves;

In order to counteract this, Entity dismount/exit vehicle events have
been modified to supress cancellation (and has a method to allow plugins
to check if this has been set), noting that cancellation will be silently
surpressed given that plugins are not expecting this event to not be cancellable.

This is a far from ideal scenario, however: given the current state of this
event and other alternatives causing issues elsewhere, I believe that
this is going to be the best soultion all around.

Improvements/suggestions welcome!

diff --git a/src/main/java/net/minecraft/server/level/ServerPlayer.java b/src/main/java/net/minecraft/server/level/ServerPlayer.java
index b4240bdd2d2baf91f52458602e0063f746dcfb6d..39504d27b8e0bae74c41e89ebabced1c25d30a7b 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
@@ -2518,9 +2518,15 @@ public class ServerPlayer extends net.minecraft.world.entity.player.Player {
 
     @Override
     public void stopRiding() {
+        // Paper start - Force entity dismount during teleportation
+        this.stopRiding(false);
+    }
+    @Override
+    public void stopRiding(boolean suppressCancellation) {
+        // Paper end - Force entity dismount during teleportation
         Entity entity = this.getVehicle();
 
-        super.stopRiding();
+        super.stopRiding(suppressCancellation); // Paper - Force entity dismount during teleportation
         if (entity instanceof LivingEntity entityliving) {
             Iterator iterator = entityliving.getActiveEffects().iterator();
 
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 131eda47e7a9f90a4057607870acbcb8fecfbf0b..2e376b0b2bf2d49ad0669b6e6fd287628a72ea64 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -2705,17 +2705,28 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
     }
 
     public void removeVehicle() {
+        // Paper start - Force entity dismount during teleportation
+        this.removeVehicle(false);
+    }
+    public void removeVehicle(boolean suppressCancellation) {
+        // Paper end - Force entity dismount during teleportation
         if (this.vehicle != null) {
             Entity entity = this.vehicle;
 
             this.vehicle = null;
-            if (!entity.removePassenger(this)) this.vehicle = entity; // CraftBukkit
+            if (!entity.removePassenger(this, suppressCancellation)) this.vehicle = entity; // CraftBukkit // Paper - Force entity dismount during teleportation
         }
 
     }
 
     public void stopRiding() {
-        this.removeVehicle();
+        // Paper start - Force entity dismount during teleportation
+        this.stopRiding(false);
+    }
+
+    public void stopRiding(boolean suppressCancellation) {
+        this.removeVehicle(suppressCancellation);
+        // Paper end - Force entity dismount during teleportation
     }
 
     protected void addPassenger(Entity passenger) {
@@ -2740,7 +2751,10 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
         }
     }
 
-    protected boolean removePassenger(Entity entity) { // CraftBukkit
+    // Paper start - Force entity dismount during teleportation
+    protected boolean removePassenger(Entity entity) { return removePassenger(entity, false);}
+    protected boolean removePassenger(Entity entity, boolean suppressCancellation) { // CraftBukkit
+        // Paper end - Force entity dismount during teleportation
         if (entity.getVehicle() == this) {
             throw new IllegalStateException("Use x.stopRiding(y), not y.removePassenger(x)");
         } else {
@@ -2750,7 +2764,7 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
             if (this.getBukkitEntity() instanceof Vehicle && entity.getBukkitEntity() instanceof LivingEntity) {
                 VehicleExitEvent event = new VehicleExitEvent(
                         (Vehicle) this.getBukkitEntity(),
-                        (LivingEntity) entity.getBukkitEntity()
+                        (LivingEntity) entity.getBukkitEntity(), !suppressCancellation // Paper - Force entity dismount during teleportation
                 );
                 // Suppress during worldgen
                 if (this.valid) {
@@ -2763,7 +2777,7 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
                 }
             }
 
-            EntityDismountEvent event = new EntityDismountEvent(entity.getBukkitEntity(), this.getBukkitEntity());
+            EntityDismountEvent event = new EntityDismountEvent(entity.getBukkitEntity(), this.getBukkitEntity(), !suppressCancellation); // Paper - Force entity dismount during teleportation
             // Suppress during worldgen
             if (this.valid) {
                 Bukkit.getPluginManager().callEvent(event);
diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index 314fcbeffe3b0adcfbd59b744001b520d6d64a0c..1ac5e457257748261088f582ed26b94e0e18eced 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -3591,9 +3591,15 @@ public abstract class LivingEntity extends Entity implements Attackable {
 
     @Override
     public void stopRiding() {
+        // Paper start - Force entity dismount during teleportation
+        this.stopRiding(false);
+    }
+    @Override
+    public void stopRiding(boolean suppressCancellation) {
+        // Paper end - Force entity dismount during teleportation
         Entity entity = this.getVehicle();
 
-        super.stopRiding();
+        super.stopRiding(suppressCancellation); // Paper - Force entity dismount during teleportation
         if (entity != null && entity != this.getVehicle() && !this.level().isClientSide) {
             this.dismountVehicle(entity);
         }
diff --git a/src/main/java/net/minecraft/world/entity/monster/Shulker.java b/src/main/java/net/minecraft/world/entity/monster/Shulker.java
index 882236c8ebad90ed2adc873de4dda3b7f3f869d9..632b74e84d6ee58da8806e30b75e16fb864afa64 100644
--- a/src/main/java/net/minecraft/world/entity/monster/Shulker.java
+++ b/src/main/java/net/minecraft/world/entity/monster/Shulker.java
@@ -288,7 +288,13 @@ public class Shulker extends AbstractGolem implements VariantHolder<Optional<Dye
 
     @Override
     public void stopRiding() {
-        super.stopRiding();
+        // Paper start - Force entity dismount during teleportation
+        this.stopRiding(false);
+    }
+    @Override
+    public void stopRiding(boolean suppressCancellation) {
+        super.stopRiding(suppressCancellation);
+        // Paper end - Force entity dismount during teleportation
         if (this.level().isClientSide) {
             this.clientOldAttachPosition = this.blockPosition();
         }
diff --git a/src/main/java/net/minecraft/world/entity/player/Player.java b/src/main/java/net/minecraft/world/entity/player/Player.java
index e60da80cbc2d2dbb98287470e1741fa2a3f95335..e7fc0f6d1a50e82c4c9fc75ca9190f63c5964f3b 100644
--- a/src/main/java/net/minecraft/world/entity/player/Player.java
+++ b/src/main/java/net/minecraft/world/entity/player/Player.java
@@ -1160,7 +1160,13 @@ public abstract class Player extends LivingEntity {
 
     @Override
     public void removeVehicle() {
-        super.removeVehicle();
+        // Paper start - Force entity dismount during teleportation
+        this.removeVehicle(false);
+    }
+    @Override
+    public void removeVehicle(boolean suppressCancellation) {
+        super.removeVehicle(suppressCancellation);
+        // Paper end - Force entity dismount during teleportation
         this.boardingCooldown = 0;
     }