Possible fix for spawning bugs... TODO implement better

src/main/java/net/citizensnpcs/Citizens.java

@@ -210,17 +210,9 @@ public class Citizens extends JavaPlugin implements CitizensPlugin {
         CitizensAPI.setImplementation(this);
 
         getServer().getPluginManager().registerEvents(new EventListen(), this);
+
         if (Setting.NPC_COST.asDouble() > 0) {
-            try {
+            setupEconomy();
-                RegisteredServiceProvider<Economy> provider = Bukkit.getServicesManager().getRegistration(
-                        Economy.class);
-                if (provider != null && provider.getProvider() != null) {
-                    Economy economy = provider.getProvider();
-                    Bukkit.getPluginManager().registerEvents(new PaymentListener(economy), this);
-                }
-            } catch (NoClassDefFoundError e) {
-                Messaging.log("Unable to use economy handling. Has Vault been enabled?");
-            }
         }
 
         registerCommands();
@@ -244,6 +236,19 @@ public class Citizens extends JavaPlugin implements CitizensPlugin {
         }
     }
 
+    private void setupEconomy() {
+        try {
+            RegisteredServiceProvider<Economy> provider = Bukkit.getServicesManager().getRegistration(
+                    Economy.class);
+            if (provider != null && provider.getProvider() != null) {
+                Economy economy = provider.getProvider();
+                Bukkit.getPluginManager().registerEvents(new PaymentListener(economy), this);
+            }
+        } catch (NoClassDefFoundError e) {
+            Messaging.log("Unable to use economy handling. Has Vault been enabled?");
+        }
+    }
+
     @Override
     public void onImplementationChanged() {
         Messaging.severe("Citizens implementation changed, disabling plugin.");

src/main/java/net/citizensnpcs/EventListen.java

@@ -55,6 +55,10 @@ public class EventListen implements Listener {
     private final NPCRegistry npcRegistry = CitizensAPI.getNPCRegistry();
     private final ListMultimap<ChunkCoord, Integer> toRespawn = ArrayListMultimap.create();
 
+    public EventListen() {
+        instance = this;
+    }
+
     /*
      * Chunk events
      */
@@ -283,4 +287,12 @@ public class EventListen implements Listener {
             return prime * (prime + x) + z;
         }
     }
+
+    public static void add(Location loc, int id) {
+        if (instance == null)
+            return;
+        instance.toRespawn.put(instance.toCoord(loc.getChunk()), id);
+    }
+
+    private static EventListen instance;
 }

src/main/java/net/citizensnpcs/npc/CitizensNPC.java

@@ -1,5 +1,6 @@
 package net.citizensnpcs.npc;
 
+import net.citizensnpcs.EventListen;
 import net.citizensnpcs.api.CitizensAPI;
 import net.citizensnpcs.api.ai.Navigator;
 import net.citizensnpcs.api.event.NPCDespawnEvent;
@@ -132,15 +133,25 @@ public abstract class CitizensNPC extends AbstractNPC {
             Messaging.debug("NPC (ID: " + getId() + ") is already spawned.");
             return false;
         }
-        NPCSpawnEvent spawnEvent = new NPCSpawnEvent(this, loc);
-        Bukkit.getPluginManager().callEvent(spawnEvent);
-        if (spawnEvent.isCancelled())
-            return false;
 
         mcEntity = createHandle(loc);
 
-        mcEntity.world.addEntity(mcEntity, SpawnReason.CUSTOM);
+        boolean couldSpawn = mcEntity.world.addEntity(mcEntity, SpawnReason.CUSTOM);
+        if (!couldSpawn) {
+            // we need to wait for a chunk load before trying to spawn
+            mcEntity = null;
+            EventListen.add(loc, getId());
+            return true;
+        }
         mcEntity.world.players.remove(mcEntity);
+
+        NPCSpawnEvent spawnEvent = new NPCSpawnEvent(this, loc);
+        Bukkit.getPluginManager().callEvent(spawnEvent);
+        if (spawnEvent.isCancelled()) {
+            mcEntity = null;
+            return false;
+        }
+
         getBukkitEntity().setMetadata(NPC_METADATA_MARKER,
                 new FixedMetadataValue(CitizensAPI.getPlugin(), true));
 

src/main/java/net/citizensnpcs/npc/ai/MCTargetStrategy.java

@@ -5,6 +5,7 @@ import net.citizensnpcs.api.ai.NavigatorParameters;
 import net.citizensnpcs.api.ai.TargetType;
 import net.citizensnpcs.api.ai.event.CancelReason;
 import net.citizensnpcs.npc.CitizensNPC;
+import net.citizensnpcs.util.NMS;
 import net.citizensnpcs.util.Util;
 import net.minecraft.server.EntityLiving;
 import net.minecraft.server.EntityMonster;
@@ -90,12 +91,12 @@ public class MCTargetStrategy implements PathStrategy, EntityTarget {
         }
         if (cancelReason != null)
             return true;
+        navigation.a(parameters.avoidWater());
         navigation.a(target, parameters.speed());
-        handle.getControllerLook().a(target, 10.0F, handle.bf());
+        NMS.look(handle.getControllerLook(), handle, target);
         if (aggro && canAttack()) {
             if (handle instanceof EntityMonster) {
-                ((EntityMonster) handle).k(target);
+                NMS.attack(handle, target);
-                // the cast is necessary to resolve overloaded method a
             } else if (handle instanceof EntityPlayer) {
                 EntityPlayer humanHandle = (EntityPlayer) handle;
                 humanHandle.attack(target);

src/main/java/net/citizensnpcs/util/NMS.java

@@ -5,6 +5,7 @@ import java.util.List;
 import java.util.Map;
 
 import net.citizensnpcs.npc.CitizensNPC;
+import net.minecraft.server.ControllerLook;
 import net.minecraft.server.Entity;
 import net.minecraft.server.EntityLiving;
 import net.minecraft.server.EntityTypes;
@@ -159,4 +160,12 @@ public class NMS {
         } catch (Exception e) {
         }
     }
+
+    public static void attack(EntityLiving handle, EntityLiving target) {
+        handle.k(target);
+    }
+
+    public static void look(ControllerLook controllerLook, EntityLiving handle, EntityLiving target) {
+        controllerLook.a(target, 10.0F, handle.bf());
+    }
 }