Implement deprecated getItemStack method in ItemTypeRecipeChoice (#13607)

Author: Warriorrrr

paper-api/src/main/java/org/bukkit/inventory/EmptyRecipeChoice.java

@@ -9,6 +9,7 @@ record EmptyRecipeChoice() implements RecipeChoice {
 
     static final RecipeChoice INSTANCE = new EmptyRecipeChoice();
     @Override
+    @Deprecated(since = "1.13.1")
     public ItemStack getItemStack() {
         throw new UnsupportedOperationException("This is an empty RecipeChoice");
     }

paper-api/src/main/java/org/bukkit/inventory/ItemTypeRecipeChoiceImpl.java

@@ -31,8 +31,17 @@ final class ItemTypeRecipeChoiceImpl extends RecipeChoice.MaterialChoice impleme
     }
 
     @Override
+    @Deprecated(since = "1.13.1")
     public ItemStack getItemStack() {
-        throw new UnsupportedOperationException("ItemTypeChoice does not support this");
+        final ItemType type = Registry.ITEM.getOrThrow(this.itemTypes.iterator().next());
+        final ItemStack item = type.createItemStack();
+
+        // legacy compat
+        if (this.itemTypes.size() > 1) {
+            item.setDurability(Short.MAX_VALUE);
+        }
+
+        return item;
     }
 
     @Override

paper-api/src/main/java/org/bukkit/inventory/RecipeChoice.java

@@ -152,6 +152,7 @@ public boolean test(ItemStack t) {
         }
 
         @Override
+        @Deprecated(since = "1.13.1")
         public ItemStack getItemStack() {
             ItemStack stack = new ItemStack(choices.get(0));
 
@@ -247,6 +248,7 @@ public ExactChoice(List<ItemStack> choices) {
         }
 
         @Override
+        @Deprecated(since = "1.13.1")
         public ItemStack getItemStack() {
             return choices.get(0).clone();
         }