Fix merchant inventories with custom titles

nms-patches/InventoryMerchant.patch

@@ -55,6 +55,15 @@
      public InventoryMerchant(EntityHuman entityhuman, IMerchant imerchant) {
          this.itemsInSlots = NonNullList.a(3, ItemStack.a);
          this.player = entityhuman;
+@@ -78,7 +119,7 @@
+     }
+ 
+     public IChatBaseComponent getDisplayName() {
+-        return new ChatMessage("mob.villager", new Object[0]);
++        return merchant.getScoreboardDisplayName(); // CraftBukkit
+     }
+ 
+     public boolean hasCustomName() {
 @@ -91,7 +132,7 @@
      }
  

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

@@ -270,6 +270,7 @@ public class CraftHumanEntity extends CraftLivingEntity implements HumanEntity {
                 break;
             case CREATIVE:
             case CRAFTING:
+            case MERCHANT:
                 throw new IllegalArgumentException("Can't open a " + type + " inventory!");
         }
         if (getHandle().activeContainer == formerContainer) {

src/main/java/org/bukkit/craftbukkit/inventory/CraftMerchantCustom.java

@@ -1,5 +1,6 @@
 package org.bukkit.craftbukkit.inventory;
 
+import org.apache.commons.lang.Validate;
 import net.minecraft.server.BlockPosition;
 import net.minecraft.server.ChatComponentText;
 import net.minecraft.server.EntityHuman;
@@ -23,12 +24,13 @@ public class CraftMerchantCustom extends CraftMerchant {
 
     private static class MinecraftMerchant implements IMerchant {
 
-        private final String title;
+        private final IChatBaseComponent title;
         private final MerchantRecipeList trades = new MerchantRecipeList();
         private EntityHuman tradingPlayer;
 
         public MinecraftMerchant(String title) {
-            this.title = title;
+            Validate.notNull(title, "Title cannot be null");
+            this.title = new ChatComponentText(title);
         }
 
         @Override
@@ -58,7 +60,7 @@ public class CraftMerchantCustom extends CraftMerchant {
 
         @Override
         public IChatBaseComponent getScoreboardDisplayName() {
-            return new ChatComponentText(title);
+            return title;
         }
 
         @Override