Adds some debug messages and makes sure to listen to the vehicle teleport event result

src/main/java/net/knarcraft/stargate/listener/PlayerEventListener.java

@@ -33,6 +33,7 @@ import org.bukkit.event.player.PlayerJoinEvent;
 import org.bukkit.event.player.PlayerMoveEvent;
 import org.bukkit.inventory.EquipmentSlot;
 import org.bukkit.inventory.ItemStack;
+import org.bukkit.util.Vector;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -131,6 +132,7 @@ public class PlayerEventListener implements Listener {
                 horse.setOwner(player);
             }
             //Teleport the player's vehicle
+            player.setVelocity(new Vector());
             new VehicleTeleporter(destination, (Vehicle) playerVehicle).teleportEntity(entrancePortal);
         } else {
             //Just teleport the player like normal

src/main/java/net/knarcraft/stargate/portal/teleporter/VehicleTeleporter.java

@@ -12,6 +12,7 @@ import org.bukkit.entity.Boat;
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.LivingEntity;
 import org.bukkit.entity.Vehicle;
+import org.bukkit.event.player.PlayerTeleportEvent;
 import org.bukkit.util.Vector;
 
 import java.util.List;
@@ -57,7 +58,10 @@ public class VehicleTeleporter extends EntityTeleporter {
         Vector newVelocity = newVelocityDirection.multiply(velocity);
 
         //Call the StargateEntityPortalEvent to allow plugins to change destination
-        triggerPortalEvent(origin, new StargateEntityPortalEvent(teleportingVehicle, origin, portal, exit));
+        exit = triggerPortalEvent(origin, new StargateEntityPortalEvent(teleportingVehicle, origin, portal, exit));
+        if (exit == null) {
+            return false;
+        }
 
         //Teleport the vehicle
         return teleportVehicle(exit, newVelocity, origin);
@@ -131,9 +135,15 @@ public class VehicleTeleporter extends EntityTeleporter {
         if (teleportingVehicle.eject()) {
             TeleportHelper.handleEntityPassengers(passengers, teleportingVehicle, origin, portal, exit.getDirection());
         }
-        teleportingVehicle.teleport(exit);
+        Stargate.debug("VehicleTeleporter::teleportVehicle", "Teleporting " + teleportingVehicle +
+                " to final location " + exit + " with direction " + exit.getDirection());
+        teleportingVehicle.teleport(exit, PlayerTeleportEvent.TeleportCause.PLUGIN);
         scheduler.scheduleSyncDelayedTask(Stargate.getInstance(),
-                () -> teleportingVehicle.setVelocity(newVelocity), 1);
+                () -> {
+                    Stargate.debug("VehicleTeleporter::teleportVehicle", "Setting velocity " + newVelocity +
+                            " for vehicle " + teleportingVehicle);
+                    teleportingVehicle.setVelocity(newVelocity);
+                }, 1);
     }
 
     /**

src/main/java/net/knarcraft/stargate/utility/TeleportHelper.java

@@ -4,6 +4,7 @@ import net.knarcraft.stargate.Stargate;
 import net.knarcraft.stargate.portal.Portal;
 import net.knarcraft.stargate.portal.teleporter.EntityTeleporter;
 import org.bukkit.Bukkit;
+import org.bukkit.Location;
 import org.bukkit.entity.Creature;
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.Player;
@@ -80,11 +81,20 @@ public final class TeleportHelper {
      * @param exitDirection <p>The direction of any passengers exiting the stargate</p>
      */
     public static void teleportAndAddPassenger(Entity targetVehicle, Entity passenger, Vector exitDirection) {
-        if (!passenger.teleport(targetVehicle.getLocation().clone().setDirection(exitDirection))) {
+        Location passengerExit = targetVehicle.getLocation().clone().setDirection(exitDirection);
-            Stargate.debug("handleVehiclePassengers", "Failed to teleport passenger" + passenger);
+        if (!passenger.teleport(passengerExit)) {
+            Stargate.debug("TeleportHelper::handleVehiclePassengers", "Failed to teleport passenger" +
+                    passenger);
+        } else {
+            Stargate.debug("TeleportHelper::handleVehiclePassengers", "Teleported " + passenger +
+                    " to " + passengerExit);
         }
         if (!targetVehicle.addPassenger(passenger)) {
-            Stargate.debug("handleVehiclePassengers", "Failed to add passenger" + passenger);
+            Stargate.debug("TeleportHelper::handleVehiclePassengers", "Failed to add passenger" +
+                    passenger);
+        } else {
+            Stargate.debug("TeleportHelper::handleVehiclePassengers", "Added passenger " + passenger +
+                    " to " + targetVehicle);
         }
     }
 
@@ -114,7 +124,7 @@ public final class TeleportHelper {
                     //Teleport any creatures leashed by the player in a 15-block range
                     teleportLeashedCreatures(player, origin, target);
                 }
-                TeleportHelper.teleportAndAddPassenger(entity, passenger, exitRotation);
+                teleportAndAddPassenger(entity, passenger, exitRotation);
             }, passenger instanceof Player ? Stargate.getGateConfig().waitForPlayerAfterTeleportDelay() : 0);
         }
     }