Fixed from and to worlds being the same for a PlayerTeleportEvent for crossworld teleports. Thanks for the help Rigby and Verrier! Tahg is responsible for the mess.

src/main/java/net/minecraft/server/NetServerHandler.java

@@ -358,30 +358,27 @@ public class NetServerHandler extends NetHandler implements ICommandListener {
 
     public void a(double d0, double d1, double d2, float f, float f1) {
         // CraftBukkit start - Delegate to teleport(Location)
-        teleport(new Location(getPlayer().getWorld(), d0, d1, d2, f, f1));
-    }
-
-    public boolean teleport(Location dest) {
-        // Note: the world in location is used only for the event
-        // Inter-world teleportation is handled in CraftPlayer.teleport()
-
         Player player = getPlayer();
         Location from = player.getLocation();
-        Location to = dest.clone();
+        Location to = new Location(getPlayer().getWorld(), d0, d1, d2, f, f1);
         PlayerTeleportEvent event = new PlayerTeleportEvent(player, from, to);
         server.getPluginManager().callEvent(event);
 
         from = event.getFrom();
         to = event.isCancelled() ? from : event.getTo();
 
+        teleport(to);
+    }
+
+    public void teleport(Location dest) {
         double d0, d1, d2;
         float f, f1;
 
-        d0 = to.getX();
+        d0 = dest.getX();
-        d1 = to.getY();
+        d1 = dest.getY();
-        d2 = to.getZ();
+        d2 = dest.getZ();
-        f = to.getYaw();
+        f = dest.getYaw();
-        f1 = to.getPitch();
+        f1 = dest.getPitch();
 
         // TODO: make sure this is the best way to address this.
         if (Float.isNaN(f)) {
@@ -399,9 +396,6 @@ public class NetServerHandler extends NetHandler implements ICommandListener {
         this.z = d2;
         this.player.setLocation(d0, d1, d2, f, f1);
         this.player.netServerHandler.sendPacket(new Packet13PlayerLookMove(d0, d1 + 1.6200000047683716D, d1, d2, f, f1, false));
-
-        // CraftBukkit - Returns TRUE if the teleport was successful
-        return !event.isCancelled();
     }
 
     public void a(Packet14BlockDig packet14blockdig) {

src/main/java/net/minecraft/server/ServerConfigurationManager.java

@@ -17,6 +17,7 @@ import org.bukkit.Location;
 import org.bukkit.craftbukkit.CraftServer;
 import org.bukkit.craftbukkit.CraftWorld;
 import org.bukkit.craftbukkit.command.ColouredConsoleSender;
+import org.bukkit.craftbukkit.entity.CraftPlayer;
 import org.bukkit.entity.Player;
 import org.bukkit.event.player.PlayerPortalEvent;
 import org.bukkit.event.player.PlayerQuitEvent;
@@ -256,8 +257,8 @@ public class ServerConfigurationManager {
         entityplayer1.netServerHandler.sendPacket(new Packet9Respawn(actualDimension));
         entityplayer1.a(worldserver);
         entityplayer1.dead = false;
+        entityplayer1.netServerHandler.teleport(new Location(worldserver.getWorld(), entityplayer1.locX, entityplayer1.locY, entityplayer1.locZ, entityplayer1.yaw, entityplayer1.pitch));
         // CraftBukkit end
-        entityplayer1.netServerHandler.a(entityplayer1.locX, entityplayer1.locY, entityplayer1.locZ, entityplayer1.yaw, entityplayer1.pitch);
         this.a(entityplayer1, worldserver);
         this.a(entityplayer1.dimension).addPlayer(entityplayer1);
         worldserver.addEntity(entityplayer1);
@@ -268,9 +269,10 @@ public class ServerConfigurationManager {
     }
 
     public void f(EntityPlayer entityplayer) {
+         // CraftBukkit start
         WorldServer worldserver = this.server.a(entityplayer.dimension);
-        boolean flag = false;
+        boolean flag = false; // Unused
-        byte b0;
+        int b0; // byte -> int
 
         if (entityplayer.dimension == -1) {
             b0 = 0;
@@ -278,32 +280,17 @@ public class ServerConfigurationManager {
             b0 = -1;
         }
 
-        // CraftBukkit start
-        CraftWorld oldCraftWorld =  worldserver.getWorld();
-        CraftWorld newCraftWorld =  this.server.a(b0).getWorld();
-        Location startLocation = new Location(oldCraftWorld, entityplayer.locX, entityplayer.locY, entityplayer.locZ);
-        Location endLocation;
-        if (b0 == -1) {
-            endLocation = new Location(newCraftWorld, entityplayer.locX / 8.0D, entityplayer.locY, entityplayer.locZ / 8.0D,entityplayer.yaw,entityplayer.pitch);
-        } else {
-            endLocation = new Location(newCraftWorld, entityplayer.locX * 8.0D, entityplayer.locY, entityplayer.locZ * 8.0D,entityplayer.yaw,entityplayer.pitch);
-        }
-        PlayerPortalEvent event = new PlayerPortalEvent((Player)entityplayer.getBukkitEntity(),startLocation,endLocation);
-        Bukkit.getServer().getPluginManager().callEvent(event);
-        if (event.isCancelled()) {
-            return;
-        }
-
         // entityplayer.dimension = b0;
-        WorldServer worldserver1 = this.server.a(b0);
+        // WorldServer worldserver1 = this.server.a(entityplayer.dimension);
 
-        // entityplayer.netServerHandler.sendPacket(new Packet9Respawn((byte) ((WorldServer)entityplayer.world).getWorld().getEnvironment().getId()));
+        // entityplayer.netServerHandler.sendPacket(new Packet9Respawn((byte) entityplayer.dimension));
-        // Craftbukkit end
+        // worldserver.removeEntity(entityplayer);
+        // entityplayer.dead = false;
         double d0 = entityplayer.locX;
         double d1 = entityplayer.locZ;
         double d2 = 8.0D;
 
-        if (b0 == -1) { // CraftBukkit
+        if (b0 == -1) { // entityplayer.dimension -> b0
             d0 /= d2;
             d1 /= d2;
             entityplayer.setPositionRotation(d0, entityplayer.locY, d1, entityplayer.yaw, entityplayer.pitch);
@@ -319,26 +306,43 @@ public class ServerConfigurationManager {
             }
         }
 
+        CraftWorld fromCraftWorld =  worldserver.getWorld();
+        CraftWorld toCraftWorld =  this.server.a(b0).getWorld();
+        Location startLocation = new Location(fromCraftWorld, entityplayer.locX, entityplayer.locY, entityplayer.locZ, entityplayer.yaw, entityplayer.pitch);
+        Location endLocation = new Location(toCraftWorld, d0, entityplayer.locY, d1, entityplayer.yaw, entityplayer.pitch);
+
+        PlayerPortalEvent event = new PlayerPortalEvent((Player)entityplayer.getBukkitEntity(),startLocation,endLocation);
+        Bukkit.getServer().getPluginManager().callEvent(event);
+        if (event.isCancelled()) {
+            return;
+        }
+        endLocation = event.getTo();
+
+        b0 = ((CraftWorld) endLocation.getWorld()).getHandle().dimension;
+
+        WorldServer worldserver1 = this.server.a(b0);
+
         if (entityplayer.S()) {
-            // worldserver1.addEntity(entityplayer); // CraftBukkit
+            // worldserver1.addEntity(entityplayer);
-            entityplayer.setPositionRotation(d0, entityplayer.locY, d1, entityplayer.yaw, entityplayer.pitch);
+            entityplayer.setPositionRotation(endLocation.getX(), endLocation.getY(), endLocation.getZ(), endLocation.getYaw(), endLocation.getPitch());
             worldserver1.entityJoinedWorld(entityplayer, false);
-            // CraftBukkit start - added conditional
             if (event.useTravelAgent()) {
                 worldserver1.chunkProviderServer.a = true;
                 (new PortalTravelAgent()).a(worldserver1, entityplayer);
                 worldserver1.chunkProviderServer.a = false;
-            } // CraftBukkit end
+                endLocation.setX(entityplayer.locX);
+                endLocation.setY(entityplayer.locY);
+                endLocation.setZ(entityplayer.locZ);
             }
-        /* CraftBukkit start
+        }
-        this.a(entityplayer);
+
-        entityplayer.netServerHandler.a(entityplayer.locX, entityplayer.locY, entityplayer.locZ, entityplayer.yaw, entityplayer.pitch);
+        // this.a(entityplayer);
-        entityplayer.a((World) worldserver1);
+        // entityplayer.netServerHandler.a(entityplayer.locX, entityplayer.locY, entityplayer.locZ, entityplayer.yaw, entityplayer.pitch);
-        this.a(entityplayer, worldserver1);
+        // entityplayer.a((World) worldserver1);
-        this.g(entityplayer);
+        // this.a(entityplayer, worldserver1);
-        */ // CraftBukkit end
+        // this.g(entityplayer);
-        // CraftBukkit - defer for actual teleportation
+        this.a(entityplayer, b0, endLocation);
-        a(entityplayer, b0, new Location(null, entityplayer.locX, entityplayer.locY, entityplayer.locZ));
+        // CraftBukkit end
     }
 
     public void b() {

src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java

@@ -21,6 +21,7 @@ import org.bukkit.Statistic;
 import org.bukkit.craftbukkit.CraftServer;
 import org.bukkit.craftbukkit.CraftWorld;
 import org.bukkit.entity.Player;
+import org.bukkit.event.player.PlayerTeleportEvent;
 
 public class CraftPlayer extends CraftHumanEntity implements Player {
 
@@ -198,17 +199,33 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
 
     @Override
     public boolean teleport(Location location) {
-        WorldServer oldWorld = ((CraftWorld)getWorld()).getHandle();
+        // From = Players current Location
-        WorldServer newWorld = ((CraftWorld)location.getWorld()).getHandle();
+        Location from = this.getLocation();
-        ServerConfigurationManager manager = server.getHandle();
+        // To = Players new Location if Teleport is Successful
-        EntityPlayer entity = getHandle();
+        Location to = location;
-
+        // Create & Call the Teleport Event.
-        if (oldWorld != newWorld) {
+        PlayerTeleportEvent event = new PlayerTeleportEvent((Player) this, from, to);
-            manager.a(entity, newWorld.dimension, location);
+        server.getPluginManager().callEvent(event);
-            return true; //best guess
+        // Return False to inform the Plugin that the Teleport was unsuccessful/cancelled.
-        } else {
+        if (event.isCancelled() == true) {
-            return entity.netServerHandler.teleport(location);
+            return false;
         }
+        // Update the From Location
+        from = event.getFrom();
+        // Grab the new To Location dependent on whether the event was cancelled.
+        to = event.getTo();
+        // Grab the To and From World Handles.
+        WorldServer fromWorld = ((CraftWorld) from.getWorld()).getHandle();
+        WorldServer toWorld = ((CraftWorld) to.getWorld()).getHandle();
+        // Grab the EntityPlayer
+        EntityPlayer entity = getHandle();
+        // Check if the fromWorld and toWorld are the same.
+        if (fromWorld == toWorld){
+            entity.netServerHandler.teleport(to);
+        } else {
+            server.getHandle().a(entity, toWorld.dimension, to);
+        }
+        return true;
     }
 
     public void setSneaking(boolean sneak) {