PaperMC · Machine-Maker · May 20, 2024 · May 12, 2024
@@ -1,11 +1,20 @@
 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
 From: Jake Potrebic <jake.m.potrebic@gmail.com>
 Date: Sun, 12 May 2024 10:42:42 -0700
-Subject: [PATCH] Improve Recipe validation
+Subject: [PATCH] Fix issues with recipe API
 
+Improves the validation when creating recipes
+and RecipeChoices to closer match what is
+allowed by the Codecs and StreamCodecs internally.
+
+Adds RecipeChoice#empty which is allowed in specific
+recipes and ingredient slots.
+
+Also fixes some issues regarding mutability of both ItemStack
+and implementations of RecipeChoice.
 
 diff --git a/src/main/java/org/bukkit/inventory/CookingRecipe.java b/src/main/java/org/bukkit/inventory/CookingRecipe.java
-index f7fa79393aef40027446b78bac8e9490cfafd8bc..a64dae15db89038f3eb599f2a41edf45990f4fda 100644
+index f7fa79393aef40027446b78bac8e9490cfafd8bc..07906ca1a9b39fcc6774870daa498402f7f37917 100644
 --- a/src/main/java/org/bukkit/inventory/CookingRecipe.java
 +++ b/src/main/java/org/bukkit/inventory/CookingRecipe.java
 @@ -44,10 +44,10 @@ public abstract class CookingRecipe<T extends CookingRecipe> implements Recipe,
@@ -17,7 +26,7 @@ index f7fa79393aef40027446b78bac8e9490cfafd8bc..a64dae15db89038f3eb599f2a41edf45
          this.key = key;
          this.output = new ItemStack(result);
 -        this.ingredient = input;
-+        this.ingredient = input.validate().clone(); // Paper
++        this.ingredient = input.validate(false).clone(); // Paper
          this.experience = experience;
          this.cookingTime = cookingTime;
      }
@@ -26,7 +35,7 @@ index f7fa79393aef40027446b78bac8e9490cfafd8bc..a64dae15db89038f3eb599f2a41edf45
      @NotNull
      public T setInputChoice(@NotNull RecipeChoice input) {
 -        this.ingredient = input;
-+        this.ingredient = input.validate().clone(); // Paper
++        this.ingredient = input.validate(false).clone(); // Paper
          return (T) this;
      }
 
@@ -43,6 +52,45 @@ index e4bf772f7e06f38215bee68f089b15a4fcb12817..37024b4736dd3897490ca51d08cf0790
          this.key = key;
          this.output = new ItemStack(result);
      }
+diff --git a/src/main/java/org/bukkit/inventory/EmptyRecipeChoice.java b/src/main/java/org/bukkit/inventory/EmptyRecipeChoice.java
+new file mode 100644
+index 0000000000000000000000000000000000000000..ed0ab6163f47ec843ba4f7ea4a98bb2fa315eaa1
+--- /dev/null
++++ b/src/main/java/org/bukkit/inventory/EmptyRecipeChoice.java
+@@ -0,0 +1,33 @@
++package org.bukkit.inventory;
++
++import org.checkerframework.checker.nullness.qual.NonNull;
++import org.checkerframework.framework.qual.DefaultQualifier;
++import org.jetbrains.annotations.ApiStatus;
++
++@ApiStatus.Internal
++@DefaultQualifier(NonNull.class)
++record EmptyRecipeChoice() implements RecipeChoice {
++
++    static final RecipeChoice INSTANCE = new EmptyRecipeChoice();
++    @Override
++    public ItemStack getItemStack() {
++        throw new UnsupportedOperationException("This is an empty RecipeChoice");
++    }
++
++    @SuppressWarnings("MethodDoesntCallSuperMethod")
++    @Override
++    public RecipeChoice clone() {
++        return this;
++    }
++
++    @Override
++    public boolean test(final ItemStack itemStack) {
++        return false;
++    }
++
++    @Override
++    public RecipeChoice validate(final boolean allowEmptyRecipes) {
++        if (allowEmptyRecipes) return this;
++        throw new IllegalArgumentException("empty RecipeChoice isn't allowed here");
++    }
++}
 diff --git a/src/main/java/org/bukkit/inventory/MerchantRecipe.java b/src/main/java/org/bukkit/inventory/MerchantRecipe.java
 index 39f9766a03d420340d79841197f75c8b1dd49f4a..4e59f5176fd6cf92457ad750081c253a58790b61 100644
 --- a/src/main/java/org/bukkit/inventory/MerchantRecipe.java
@@ -78,24 +126,61 @@ index 39f9766a03d420340d79841197f75c8b1dd49f4a..4e59f5176fd6cf92457ad750081c253a
          }
      }
 diff --git a/src/main/java/org/bukkit/inventory/RecipeChoice.java b/src/main/java/org/bukkit/inventory/RecipeChoice.java
-index db8bcc66bdc4bedfffb4705db6338eda4c0ad29a..c143b0d8b97d514566bac8413d0346cf50822aeb 100644
+index db8bcc66bdc4bedfffb4705db6338eda4c0ad29a..1cd6601c9d2e86ef850011fcb9e59811207b4af7 100644
 --- a/src/main/java/org/bukkit/inventory/RecipeChoice.java
 +++ b/src/main/java/org/bukkit/inventory/RecipeChoice.java
-@@ -35,6 +35,13 @@ public interface RecipeChoice extends Predicate<ItemStack>, Cloneable {
+@@ -19,6 +19,19 @@ import org.jetbrains.annotations.NotNull;
+  */
+ public interface RecipeChoice extends Predicate<ItemStack>, Cloneable {
+
++    // Paper start - add "empty" choice
++    /**
++     * An "empty" recipe choice. Only valid as a recipe choice in
++     * specific places. Check the javadocs of a method before using it
++     * to be sure it's valid for that recipe and ingredient type.
++     *
++     * @return the empty recipe choice
++     */
++    static @NotNull RecipeChoice empty() {
++        return EmptyRecipeChoice.INSTANCE;
++    }
++    // Paper end
++
+     /**
+      * Gets a single item stack representative of this stack choice.
+      *
+@@ -35,6 +48,13 @@ public interface RecipeChoice extends Predicate<ItemStack>, Cloneable {
      @Override
      boolean test(@NotNull ItemStack itemStack);
 
 +    // Paper start - check valid ingredients
 +    @org.jetbrains.annotations.ApiStatus.Internal
-+    default @NotNull RecipeChoice validate() {
++    default @NotNull RecipeChoice validate(final boolean allowEmptyRecipes) {
 +        return this;
 +    }
 +    // Paper end - check valid ingredients
 +
      /**
       * Represents a choice of multiple matching Materials.
       */
-@@ -185,7 +192,12 @@ public interface RecipeChoice extends Predicate<ItemStack>, Cloneable {
+@@ -141,6 +161,16 @@ public interface RecipeChoice extends Predicate<ItemStack>, Cloneable {
+         public String toString() {
+             return "MaterialChoice{" + "choices=" + choices + '}';
+         }
++
++        // Paper start - check valid ingredients
++        @Override
++        public @NotNull RecipeChoice validate(final boolean allowEmptyRecipes) {
++            if (this.choices.stream().anyMatch(Material::isAir)) {
++                throw new IllegalArgumentException("RecipeChoice.MaterialChoice cannot contain air");
++            }
++            return this;
++        }
++        // Paper end - check valid ingredients
+     }
+
+     /**
+@@ -185,7 +215,12 @@ public interface RecipeChoice extends Predicate<ItemStack>, Cloneable {
          public ExactChoice clone() {
              try {
                  ExactChoice clone = (ExactChoice) super.clone();
@@ -109,14 +194,14 @@ index db8bcc66bdc4bedfffb4705db6338eda4c0ad29a..c143b0d8b97d514566bac8413d0346cf
                  return clone;
              } catch (CloneNotSupportedException ex) {
                  throw new AssertionError(ex);
-@@ -232,5 +244,15 @@ public interface RecipeChoice extends Predicate<ItemStack>, Cloneable {
+@@ -232,5 +267,15 @@ public interface RecipeChoice extends Predicate<ItemStack>, Cloneable {
          public String toString() {
              return "ExactChoice{" + "choices=" + choices + '}';
          }
 +
 +        // Paper start - check valid ingredients
 +        @Override
-+        public @NotNull RecipeChoice validate() {
++        public @NotNull RecipeChoice validate(final boolean allowEmptyRecipes) {
 +            if (this.choices.stream().anyMatch(s -> s.getType().isAir())) {
 +                throw new IllegalArgumentException("RecipeChoice.ExactChoice cannot contain air");
 +            }
@@ -126,15 +211,15 @@ index db8bcc66bdc4bedfffb4705db6338eda4c0ad29a..c143b0d8b97d514566bac8413d0346cf
      }
  }
 diff --git a/src/main/java/org/bukkit/inventory/ShapedRecipe.java b/src/main/java/org/bukkit/inventory/ShapedRecipe.java
-index da878c6d4928ddbc16b50ace86d992685a2b7873..0547505987ee954adbac0cbe5a6ada3dfaedf034 100644
+index da878c6d4928ddbc16b50ace86d992685a2b7873..28e8d4e4f354b304f32cd8f14dcff7166a7bb37e 100644
 --- a/src/main/java/org/bukkit/inventory/ShapedRecipe.java
 +++ b/src/main/java/org/bukkit/inventory/ShapedRecipe.java
 @@ -166,14 +166,15 @@ public class ShapedRecipe extends CraftingRecipe {
      public ShapedRecipe setIngredient(char key, @NotNull RecipeChoice ingredient) {
          Preconditions.checkArgument(ingredients.containsKey(key), "Symbol does not appear in the shape:", key);
 
 -        ingredients.put(key, ingredient);
-+        ingredients.put(key, ingredient.validate().clone()); // Paper
++        ingredients.put(key, ingredient.validate(false).clone()); // Paper
          return this;
      }
 
@@ -148,15 +233,15 @@ index da878c6d4928ddbc16b50ace86d992685a2b7873..0547505987ee954adbac0cbe5a6ada3d
      // Paper end
 
 diff --git a/src/main/java/org/bukkit/inventory/ShapelessRecipe.java b/src/main/java/org/bukkit/inventory/ShapelessRecipe.java
-index beb798482479c58a8628c314b510ab6349576ce8..6a8195ca224790e3130ec9923188e7b585797263 100644
+index beb798482479c58a8628c314b510ab6349576ce8..8251170314ab25c26270208e453b4e3909435754 100644
 --- a/src/main/java/org/bukkit/inventory/ShapelessRecipe.java
 +++ b/src/main/java/org/bukkit/inventory/ShapelessRecipe.java
 @@ -131,7 +131,7 @@ public class ShapelessRecipe extends CraftingRecipe {
      public ShapelessRecipe addIngredient(@NotNull RecipeChoice ingredient) {
          Preconditions.checkArgument(ingredients.size() + 1 <= 9, "Shapeless recipes cannot have more than 9 ingredients");
 
 -        ingredients.add(ingredient);
-+        ingredients.add(ingredient.validate().clone()); // Paper
++        ingredients.add(ingredient.validate(false).clone()); // Paper
          return this;
      }
 
@@ -170,7 +255,7 @@ index beb798482479c58a8628c314b510ab6349576ce8..6a8195ca224790e3130ec9923188e7b5
              ingredients.add(new RecipeChoice.ExactChoice(item));
          }
 diff --git a/src/main/java/org/bukkit/inventory/SmithingRecipe.java b/src/main/java/org/bukkit/inventory/SmithingRecipe.java
-index 1ef9a715a2736e88a16083c6873803a8bd6bcf29..a8f451dc1d8d49c2080c3ed3d8348020c3d470cf 100644
+index 1ef9a715a2736e88a16083c6873803a8bd6bcf29..3072858dd4413129ec1737572838c2ea5ffd84bc 100644
 --- a/src/main/java/org/bukkit/inventory/SmithingRecipe.java
 +++ b/src/main/java/org/bukkit/inventory/SmithingRecipe.java
 @@ -44,12 +44,13 @@ public class SmithingRecipe implements Recipe, Keyed {
@@ -184,48 +269,94 @@ index 1ef9a715a2736e88a16083c6873803a8bd6bcf29..a8f451dc1d8d49c2080c3ed3d8348020
          this.result = result;
 -        this.base = base;
 -        this.addition = addition;
-+        this.base = base.validate().clone(); // Paper
-+        this.addition = addition.validate().clone(); // Paper
++        this.base = base.validate(true).clone(); // Paper
++        this.addition = addition.validate(true).clone(); // Paper
      }
 
      /**
 diff --git a/src/main/java/org/bukkit/inventory/SmithingTransformRecipe.java b/src/main/java/org/bukkit/inventory/SmithingTransformRecipe.java
-index 68e7132d77151b7b8312638d8bb79ea59e2fa5a6..d3a7070a51d15531fb6f917ca87196dfa08f83aa 100644
+index 68e7132d77151b7b8312638d8bb79ea59e2fa5a6..60bfdd6b8814be8e3ffdfaef8a5ac7eeff9a5830 100644
 --- a/src/main/java/org/bukkit/inventory/SmithingTransformRecipe.java
 +++ b/src/main/java/org/bukkit/inventory/SmithingTransformRecipe.java
-@@ -21,7 +21,7 @@ public class SmithingTransformRecipe extends SmithingRecipe {
+@@ -15,13 +15,13 @@ public class SmithingTransformRecipe extends SmithingRecipe {
+      *
+      * @param key The unique recipe key
+      * @param result The item you want the recipe to create.
+-     * @param template The template item.
+-     * @param base The base ingredient
+-     * @param addition The addition ingredient
++     * @param template The template item ({@link RecipeChoice#empty()} can be used)
++     * @param base The base ingredient ({@link RecipeChoice#empty()} can be used)
++     * @param addition The addition ingredient ({@link RecipeChoice#empty()} can be used)
       */
      public SmithingTransformRecipe(@NotNull NamespacedKey key, @NotNull ItemStack result, @NotNull RecipeChoice template, @NotNull RecipeChoice base, @NotNull RecipeChoice addition) {
          super(key, result, base, addition);
 -        this.template = template;
-+        this.template = template.validate().clone(); // Paper
++        this.template = template.validate(true).clone(); // Paper
      }
      // Paper start
      /**
+@@ -29,14 +29,14 @@ public class SmithingTransformRecipe extends SmithingRecipe {
+      *
+      * @param key The unique recipe key
+      * @param result The item you want the recipe to create.
+-     * @param template The template item.
+-     * @param base The base ingredient
+-     * @param addition The addition ingredient
++     * @param template The template item ({@link RecipeChoice#empty()} can be used)
++     * @param base The base ingredient ({@link RecipeChoice#empty()} can be used)
++     * @param addition The addition ingredient ({@link RecipeChoice#empty()} can be used)
+      * @param copyDataComponents whether to copy the data components from the input base item to the output
+      */
+     public SmithingTransformRecipe(@NotNull NamespacedKey key, @NotNull ItemStack result, @NotNull RecipeChoice template, @NotNull RecipeChoice base, @NotNull RecipeChoice addition, boolean copyDataComponents) {
+         super(key, result, base, addition, copyDataComponents);
+-        this.template = template;
++        this.template = template.validate(true).clone();
+     }
+     // Paper end
+
 diff --git a/src/main/java/org/bukkit/inventory/SmithingTrimRecipe.java b/src/main/java/org/bukkit/inventory/SmithingTrimRecipe.java
-index ce36bb5b030f17e11f74e987235be143c1925aa7..6316112074a0708734106ca9de5ef968df52ce0e 100644
+index ce36bb5b030f17e11f74e987235be143c1925aa7..9ac27cbe7dcff0403ef34727d0461b8201aca6f1 100644
 --- a/src/main/java/org/bukkit/inventory/SmithingTrimRecipe.java
 +++ b/src/main/java/org/bukkit/inventory/SmithingTrimRecipe.java
-@@ -21,7 +21,7 @@ public class SmithingTrimRecipe extends SmithingRecipe implements ComplexRecipe
+@@ -15,27 +15,27 @@ public class SmithingTrimRecipe extends SmithingRecipe implements ComplexRecipe
+      * Create a smithing recipe to produce the specified result ItemStack.
+      *
+      * @param key The unique recipe key
+-     * @param template The template item.
+-     * @param base The base ingredient
+-     * @param addition The addition ingredient
++     * @param template The template item ({@link RecipeChoice#empty()} can be used)
++     * @param base The base ingredient ({@link RecipeChoice#empty()} can be used)
++     * @param addition The addition ingredient ({@link RecipeChoice#empty()} can be used)
       */
      public SmithingTrimRecipe(@NotNull NamespacedKey key, @NotNull RecipeChoice template, @NotNull RecipeChoice base, @NotNull RecipeChoice addition) {
          super(key, new ItemStack(Material.AIR), base, addition);
 -        this.template = template;
-+        this.template = template.validate().clone(); // Paper
++        this.template = template.validate(true).clone(); // Paper
      }
      // Paper start
      /**
-@@ -35,7 +35,7 @@ public class SmithingTrimRecipe extends SmithingRecipe implements ComplexRecipe
+      * Create a smithing recipe to produce the specified result ItemStack.
+      *
+      * @param key The unique recipe key
+-     * @param template The template item.
+-     * @param base The base ingredient
+-     * @param addition The addition ingredient
++     * @param template The template item. ({@link RecipeChoice#empty()} can be used)
++     * @param base The base ingredient ({@link RecipeChoice#empty()} can be used)
++     * @param addition The addition ingredient ({@link RecipeChoice#empty()} can be used)
+      * @param copyDataComponents whether to copy the data components from the input base item to the output
       */
      public SmithingTrimRecipe(@NotNull NamespacedKey key, @NotNull RecipeChoice template, @NotNull RecipeChoice base, @NotNull RecipeChoice addition, boolean copyDataComponents) {
          super(key, new ItemStack(Material.AIR), base, addition, copyDataComponents);
 -        this.template = template;
-+        this.template = template.validate().clone(); // Paper
++        this.template = template.validate(true).clone(); // Paper
      }
      // Paper end
 
 diff --git a/src/main/java/org/bukkit/inventory/StonecuttingRecipe.java b/src/main/java/org/bukkit/inventory/StonecuttingRecipe.java
-index bc3440eb72127824b3961fbdae583bb61385f65e..802c23a86d301a5336a97a8256182da7d792ec1d 100644
+index bc3440eb72127824b3961fbdae583bb61385f65e..17b33f8e6e3dc6a22686a498fa944382e8767077 100644
 --- a/src/main/java/org/bukkit/inventory/StonecuttingRecipe.java
 +++ b/src/main/java/org/bukkit/inventory/StonecuttingRecipe.java
 @@ -35,10 +35,10 @@ public class StonecuttingRecipe implements Recipe, Keyed {
@@ -237,7 +368,7 @@ index bc3440eb72127824b3961fbdae583bb61385f65e..802c23a86d301a5336a97a8256182da7
          this.key = key;
          this.output = new ItemStack(result);
 -        this.ingredient = input;
-+        this.ingredient = input.validate().clone(); // Paper
++        this.ingredient = input.validate(false).clone(); // Paper
      }
 
      /**
@@ -246,7 +377,7 @@ index bc3440eb72127824b3961fbdae583bb61385f65e..802c23a86d301a5336a97a8256182da7
      @NotNull
      public StonecuttingRecipe setInputChoice(@NotNull RecipeChoice input) {
 -        this.ingredient = input;
-+        this.ingredient = input.validate().clone(); // Paper
++        this.ingredient = input.validate(false).clone(); // Paper
          return (StonecuttingRecipe) this;
      }