PaperMC/nms-patches/ItemMapEmpty.patch

--- ../work/decompile-8eb82bde//net/minecraft/server/ItemMapEmpty.java	Wed Dec 17 16:16:12 2014
+++ src/main/java/net/minecraft/server/ItemMapEmpty.java	Wed Dec 17 16:16:12 2014
@@ -7,15 +7,19 @@
     }
 
     public ItemStack a(ItemStack itemstack, World world, EntityHuman entityhuman) {
-        ItemStack itemstack1 = new ItemStack(Items.FILLED_MAP, 1, world.b("map"));
+        World worldMain = world.getServer().getServer().worlds.get(0); // CraftBukkit - store reference to primary world
+        ItemStack itemstack1 = new ItemStack(Items.FILLED_MAP, 1, worldMain.b("map")); // CraftBukkit - use primary world for maps
         String s = "map_" + itemstack1.getData();
         WorldMap worldmap = new WorldMap(s);
 
-        world.a(s, (PersistentBase) worldmap);
+        worldMain.a(s, (PersistentBase) worldmap);
         worldmap.scale = 0;
         worldmap.a(entityhuman.locX, entityhuman.locZ, worldmap.scale);
-        worldmap.map = (byte) world.worldProvider.getDimension();
+        worldmap.map = (byte) ((WorldServer) world).dimension; // CraftBukkit - use bukkit dimension
         worldmap.c();
+        
+        org.bukkit.craftbukkit.event.CraftEventFactory.callEvent(new org.bukkit.event.server.MapInitializeEvent(worldmap.mapView)); // CraftBukkit
+        
         --itemstack.count;
         if (itemstack.count <= 0) {
             return itemstack1;