PaperMC/paper-server/nms-patches/net/minecraft/world/item/crafting/CraftingManager.patch

--- a/net/minecraft/world/item/crafting/CraftingManager.java
+++ b/net/minecraft/world/item/crafting/CraftingManager.java
@@ -34,6 +34,11 @@
 import net.minecraft.world.level.World;
 import org.slf4j.Logger;
 
+// CraftBukkit start
+import com.google.common.collect.LinkedHashMultimap;
+import com.google.common.collect.Maps;
+// CraftBukkit end
+
 public class CraftingManager extends ResourceDataJson {
 
     private static final Gson GSON = (new GsonBuilder()).setPrettyPrinting().disableHtmlEscaping().create();
@@ -70,19 +75,39 @@
             }
         }
 
-        this.byType = builder.build();
-        this.byName = com_google_common_collect_immutablemap_builder.build();
+        // CraftBukkit start - mutable
+        this.byType = LinkedHashMultimap.create(builder.build());
+        this.byName = Maps.newHashMap(com_google_common_collect_immutablemap_builder.build());
+        // CraftBukkit end
         CraftingManager.LOGGER.info("Loaded {} recipes", this.byType.size());
     }
 
+    // CraftBukkit start
+    public void addRecipe(RecipeHolder<?> irecipe) {
+        Collection<RecipeHolder<?>> map = this.byType.get(irecipe.value().getType()); // CraftBukkit
+
+        if (byName.containsKey(irecipe.id())) {
+            throw new IllegalStateException("Duplicate recipe ignored with ID " + irecipe.id());
+        } else {
+            map.add(irecipe);
+            byName.put(irecipe.id(), irecipe);
+        }
+    }
+    // CraftBukkit end
+
     public boolean hadErrorsLoading() {
         return this.hasErrors;
     }
 
     public <C extends IInventory, T extends IRecipe<C>> Optional<RecipeHolder<T>> getRecipeFor(Recipes<T> recipes, C c0, World world) {
-        return this.byType(recipes).stream().filter((recipeholder) -> {
+        // CraftBukkit start
+        List<RecipeHolder<T>> list = this.byType(recipes).stream().filter((recipeholder) -> {
             return recipeholder.value().matches(c0, world);
-        }).findFirst();
+        }).toList();
+        Optional<RecipeHolder<T>> recipe = (list.isEmpty()) ? Optional.empty() : Optional.of(list.getLast()); // CraftBukkit - SPIGOT-4638: last recipe gets priority
+        c0.setCurrentRecipe(recipe.orElse(null)); // CraftBukkit - Clear recipe when no recipe is found
+        return recipe;
+        // CraftBukkit end
     }
 
     public <C extends IInventory, T extends IRecipe<C>> Optional<RecipeHolder<T>> getRecipeFor(Recipes<T> recipes, C c0, World world, @Nullable MinecraftKey minecraftkey) {
@@ -94,9 +119,14 @@
             }
         }
 
-        return this.byType(recipes).stream().filter((recipeholder1) -> {
+        // CraftBukkit start
+        List<RecipeHolder<T>> list = this.byType(recipes).stream().filter((recipeholder1) -> {
             return recipeholder1.value().matches(c0, world);
-        }).findFirst();
+        }).toList();
+        Optional<RecipeHolder<T>> recipe = (list.isEmpty()) ? Optional.empty() : Optional.of(list.getLast()); // CraftBukkit - SPIGOT-4638: last recipe gets priority
+        c0.setCurrentRecipe(recipe.orElse(null)); // CraftBukkit - Clear recipe when no recipe is found
+        return recipe;
+        // CraftBukkit end
     }
 
     public <C extends IInventory, T extends IRecipe<C>> List<RecipeHolder<T>> getAllRecipesFor(Recipes<T> recipes) {
@@ -112,7 +142,7 @@
     }
 
     private <C extends IInventory, T extends IRecipe<C>> Collection<RecipeHolder<T>> byType(Recipes<T> recipes) {
-        return this.byType.get(recipes);
+        return (Collection) this.byType.get(recipes); // CraftBukkit - decompile error
     }
 
     public <C extends IInventory, T extends IRecipe<C>> NonNullList<ItemStack> getRemainingItemsFor(Recipes<T> recipes, C c0, World world) {
@@ -139,7 +169,7 @@
     private <T extends IRecipe<?>> RecipeHolder<T> byKeyTyped(Recipes<T> recipes, MinecraftKey minecraftkey) {
         RecipeHolder<?> recipeholder = (RecipeHolder) this.byName.get(minecraftkey);
 
-        return recipeholder != null && recipeholder.value().getType().equals(recipes) ? recipeholder : null;
+        return recipeholder != null && recipeholder.value().getType().equals(recipes) ? (RecipeHolder) recipeholder : null; // CraftBukkit - decompile error
     }
 
     public Collection<RecipeHolder<?>> getOrderedRecipes() {
@@ -175,10 +205,31 @@
             com_google_common_collect_immutablemap_builder.put(recipeholder.id(), recipeholder);
         }
 
-        this.byType = builder.build();
-        this.byName = com_google_common_collect_immutablemap_builder.build();
+        // CraftBukkit start - mutable
+        this.byType = LinkedHashMultimap.create(builder.build());
+        this.byName = Maps.newHashMap(com_google_common_collect_immutablemap_builder.build());
+        // CraftBukkit end
     }
 
+    // CraftBukkit start
+    public boolean removeRecipe(MinecraftKey mcKey) {
+        Iterator<RecipeHolder<?>> iter = byType.values().iterator();
+        while (iter.hasNext()) {
+            RecipeHolder<?> recipe = iter.next();
+            if (recipe.id().equals(mcKey)) {
+                iter.remove();
+            }
+        }
+
+        return byName.remove(mcKey) != null;
+    }
+
+    public void clearRecipes() {
+        this.byType = LinkedHashMultimap.create();
+        this.byName = Maps.newHashMap();
+    }
+    // CraftBukkit end
+
     public static <C extends IInventory, T extends IRecipe<C>> CraftingManager.a<C, T> createCheck(final Recipes<T> recipes) {
         return new CraftingManager.a<C, T>() {
             @Nullable