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 8de0b92285fe2413a4e2fb52fc7bc7a13dad5e90..fcbb0b64feb8d5624de3805d4db6d489110b4e69 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
@@ -2519,9 +2519,15 @@ 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 3830440b913bd2693f2922483e57419c76117315..5b3de422b07f680e6639ee84f076bffb3c901d0e 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -2706,17 +2706,28 @@ 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) {
@@ -2741,7 +2752,10 @@ 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 {
@@ -2751,7 +2765,7 @@ 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) {
@@ -2764,7 +2778,7 @@ 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 bf493378dca5f9ebb4e098c7552d9fdb1ea1822d..d73f3ca9ff9584628ab9b0434d76368a20bca51e 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 28cbe9ac2b8d5a21dba11b4162d187a9333e1ddb..e8fb36582430332e511c2d7ac1e604763f4052e3 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;
     }