Paper/Spigot-Server-Patches/0316-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 f05f24f2a5c4ba8dbb8572d113afc404259e73ed..cf63703f5f38b1531912d413b0ac16c23627ca34 100644
--- a/src/main/java/net/minecraft/server/level/EntityPlayer.java
+++ b/src/main/java/net/minecraft/server/level/EntityPlayer.java
@@ -1252,11 +1252,13 @@ 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 1f5ab7d43315fa3a67297eabea3bda257ed24a44..dca0bab93b5a1460c4741b0517b41490eb62703e 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -2039,12 +2039,15 @@ 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
         }
 
     }
@@ -2099,7 +2102,10 @@ 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 {
@@ -2109,7 +2115,7 @@ 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) {
@@ -2123,7 +2129,7 @@ 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 c189a7051240bb357acf5075c98206a258409b0c..58270f45de665b5c1cfd9fc548eadb263ad230e9 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 bed54f9732bbfe9edab81744276643da482785d3..6dc1d03e755cd4c268de71ebba7e771a640938c2 100644
--- a/src/main/java/net/minecraft/world/entity/player/EntityHuman.java
+++ b/src/main/java/net/minecraft/world/entity/player/EntityHuman.java
@@ -1036,9 +1036,11 @@ 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;
     }