Paper/patches/server/0289-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 222452a5549e29ef43d183390cc41783aeb8f3e9..3e50915041041486dc6dd939609bcd2673cd2ad2 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
@@ -1336,11 +1336,13 @@ public class ServerPlayer extends Player {
         }
     }
 
-    @Override
-    public void stopRiding() {
+    // Paper start
+    @Override public void stopRiding() { stopRiding(false); }
+    @Override public void stopRiding(boolean suppressCancellation) {
+        // Paper end
         Entity entity = this.getVehicle();
 
-        super.stopRiding();
+        super.stopRiding(suppressCancellation); // Paper
         Entity entity1 = this.getVehicle();
 
         if (entity1 != entity && this.connection != null) {
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index a279b7473a4e3397898707bf232c7866aacee9d1..18fe107cee949495d2eb7525526d96390c04b0d6 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -2278,11 +2278,16 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
     }
 
     public void removeVehicle() {
+        // Paper start
+        stopRiding(false);
+    }
+    public void stopRiding(boolean suppressCancellation) {
+        // Paper end
         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
         }
 
     }
@@ -2345,7 +2350,10 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
         return true; // CraftBukkit
     }
 
-    protected boolean removePassenger(Entity entity) { // CraftBukkit
+    // Paper start
+    protected boolean removePassenger(Entity entity) { return removePassenger(entity, false);}
+    protected boolean removePassenger(Entity entity, boolean suppressCancellation) { // CraftBukkit
+        // Paper end
         if (entity.getVehicle() == this) {
             throw new IllegalStateException("Use x.stopRiding(y), not y.removePassenger(x)");
         } else {
@@ -2355,7 +2363,7 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
             if (this.getBukkitEntity() instanceof Vehicle && entity.getBukkitEntity() instanceof LivingEntity) {
                 VehicleExitEvent event = new VehicleExitEvent(
                         (Vehicle) this.getBukkitEntity(),
-                        (LivingEntity) entity.getBukkitEntity()
+                        (LivingEntity) entity.getBukkitEntity(), !suppressCancellation // Paper
                 );
                 // Suppress during worldgen
                 if (this.valid) {
@@ -2369,7 +2377,7 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
             }
             // CraftBukkit end
             // Spigot start
-            org.spigotmc.event.entity.EntityDismountEvent event = new org.spigotmc.event.entity.EntityDismountEvent(entity.getBukkitEntity(), this.getBukkitEntity());
+            org.spigotmc.event.entity.EntityDismountEvent event = new org.spigotmc.event.entity.EntityDismountEvent(entity.getBukkitEntity(), this.getBukkitEntity(), !suppressCancellation); // Paper
             // 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 370ec54f5c6741e7c9f3630e7f42ea7d7a7d1423..3ea28ff50d409d1d234d17f62207b0585386a607 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -3379,9 +3379,15 @@ public abstract class LivingEntity extends Entity {
 
     @Override
     public void stopRiding() {
+        // Paper start
+        stopRiding(false);
+    }
+    @Override
+    public void stopRiding(boolean suppressCancellation) {
+        // Paper end
         Entity entity = this.getVehicle();
 
-        super.stopRiding();
+        super.stopRiding(suppressCancellation); // Paper - suppress
         if (entity != null && entity != this.getVehicle() && !this.level.isClientSide) {
             this.dismountVehicle(entity);
         }
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 d44d472326d70fe60c5c975109aa7dc5f1971b5d..9b8c73b06850e40f69b70bdb6c8a3a86d678b645 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
+        stopRiding(false);
+    }
+    @Override
+    public void stopRiding(boolean suppressCancellation) {
+        // Paper end
+        super.stopRiding(suppressCancellation); // Paper - suppress
         this.boardingCooldown = 0;
     }