Paper/patches/server/0268-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 dad9d89d77001d2c84fbae7a8a4a4312cc5953dc..ae7a5e65b9183338ce5ed44807a493ce1f3e8c93 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
@@ -2522,9 +2522,15 @@ 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 43eddcd8496ff2f089119f6632acfe1b56466c3d..e047911c7faa3cdcd3df8899857fcadf3eec3d89 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -3619,9 +3619,15 @@ 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 b70fbc1a93271bbf28402afbe9c6e538a4b6e9aa..fa906334a1c569748d3f2dc073ec03a85bd09d3b 100644
--- a/src/main/java/net/minecraft/world/entity/player/Player.java
+++ b/src/main/java/net/minecraft/world/entity/player/Player.java
@@ -1161,7 +1161,13 @@ 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;
     }