Paper/Spigot-Server-Patches/0315-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/EntityPlayer.java b/src/main/java/net/minecraft/server/level/EntityPlayer.java
index 3e7ac6699ad1f147220c286e251ce0ec1ca25035..e755191435e74246b309f8fe5a668dae2e499df1 100644
--- a/src/main/java/net/minecraft/server/level/EntityPlayer.java
+++ b/src/main/java/net/minecraft/server/level/EntityPlayer.java
@@ -1261,11 +1261,13 @@ public class EntityPlayer extends EntityHuman implements ICrafting {
         }
     }
 
-    @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.playerConnection != null) {
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 0b61d03506bd56cf7e373daacbf4fb2e29bb0a58..1e5930f5ae75b82abf6ea2a50558449fb667016f 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -2040,12 +2040,15 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, ne
 
     }
 
-    public void bf() {
+    // Paper start
+    public void bf() { 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
         }
 
     }
@@ -2100,7 +2103,10 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, ne
         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 {
@@ -2110,7 +2116,7 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, ne
             if (getBukkitEntity() instanceof Vehicle && entity.getBukkitEntity() instanceof LivingEntity) {
                 VehicleExitEvent event = new VehicleExitEvent(
                         (Vehicle) getBukkitEntity(),
-                        (LivingEntity) entity.getBukkitEntity()
+                        (LivingEntity) entity.getBukkitEntity(), !suppressCancellation // Paper
                 );
                 // Suppress during worldgen
                 if (this.valid) {
@@ -2124,7 +2130,7 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, ne
             }
             // 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/EntityLiving.java b/src/main/java/net/minecraft/world/entity/EntityLiving.java
index b3c2976a48c2349e5c22d58dd1ac64a02cd969d5..6ada2fe58966553b52a8a890088c78d5ea0dfd73 100644
--- a/src/main/java/net/minecraft/world/entity/EntityLiving.java
+++ b/src/main/java/net/minecraft/world/entity/EntityLiving.java
@@ -3015,11 +3015,13 @@ public abstract class EntityLiving extends Entity {
         return ((Byte) this.datawatcher.get(EntityLiving.ag) & 4) != 0;
     }
 
-    @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 - suppress
         if (entity != null && entity != this.getVehicle() && !this.world.isClientSide) {
             this.a(entity);
         }
diff --git a/src/main/java/net/minecraft/world/entity/player/EntityHuman.java b/src/main/java/net/minecraft/world/entity/player/EntityHuman.java
index 87374174dcbf9e7ee448a1cdd9a3528557c3a2ea..564dfa98c166fde509044e6e1938efb321ece53d 100644
--- a/src/main/java/net/minecraft/world/entity/player/EntityHuman.java
+++ b/src/main/java/net/minecraft/world/entity/player/EntityHuman.java
@@ -1039,9 +1039,11 @@ public abstract class EntityHuman extends EntityLiving {
         return -0.35D;
     }
 
-    @Override
-    public void bf() {
-        super.bf();
+    // Paper start
+    @Override public void bf() { stopRiding(false); }
+    @Override public void stopRiding(boolean suppressCancellation) {
+        // Paper end
+        super.stopRiding(suppressCancellation); // Paper - suppress
         this.j = 0;
     }