fix(create): diamond dupe via mixer ignoring ingredient count

Create 6.x deserializes item ingredients of processing recipes with
plain Ingredient.CODEC, silently ignoring the "count" field. The
mixing recipe (9 shards -> 1 diamond, written as one ingredient with
count: 9) only consumed 1 shard per diamond; combined with
crushing/milling (1 diamond -> ~6 shards) this created an infinite
diamond duplication loop.

- List the shard 9 times as single-item ingredients (BasinRecipe
  consumes exactly 1 item per ingredient entry)
- Add CreateCompatRecipesTest guarding the invariants: 9 shards per
  diamond in mixing+crafting, and crushing/milling expected yield
  stays below 9 shards per diamond (loop can never be net-positive)

src/main/resources/data/create/recipe/mixing/diamond_shard_to_diamond.json

@@ -8,8 +8,31 @@
   "type": "create:mixing",
   "ingredients": [
     {
-      "item": "custom_ore_gen:diamondshard",
-      "count": 9
+      "item": "custom_ore_gen:diamondshard"
+    },
+    {
+      "item": "custom_ore_gen:diamondshard"
+    },
+    {
+      "item": "custom_ore_gen:diamondshard"
+    },
+    {
+      "item": "custom_ore_gen:diamondshard"
+    },
+    {
+      "item": "custom_ore_gen:diamondshard"
+    },
+    {
+      "item": "custom_ore_gen:diamondshard"
+    },
+    {
+      "item": "custom_ore_gen:diamondshard"
+    },
+    {
+      "item": "custom_ore_gen:diamondshard"
+    },
+    {
+      "item": "custom_ore_gen:diamondshard"
     }
   ],
   "results": [
@@ -19,4 +42,4 @@
     }
   ],
   "processing_time": 100
-}
+}

src/test/java/net/mcreator/customoregen/CreateCompatRecipesTest.java

@@ -0,0 +1,139 @@
+package net.mcreator.customoregen;
+
+import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * Regression tests for the Create mod compatibility recipes (diamond shard cycle).
+ *
+ * Background: Create 6.x deserializes ITEM ingredients of processing recipes with
+ * plain {@code Ingredient.CODEC} (see ProcessingRecipeParams), which silently
+ * IGNORES the "count" field. A mixing recipe written as a single ingredient with
+ * "count": 9 was therefore consuming only 1 shard per diamond. Combined with the
+ * crushing/milling recipes (1 diamond -> ~6 shards), this created an infinite
+ * diamond duplication loop.
+ *
+ * Fix: the mixing recipe must list the shard 9 times as separate single-item
+ * ingredients (BasinRecipe consumes exactly 1 item per ingredient entry).
+ *
+ * These tests guard the invariant: SHARDS_PER_DIAMOND = 9 everywhere, and the
+ * expected yield of diamond -> shards processing must stay BELOW 9 so the cycle
+ * can never be net-positive.
+ */
+@DisplayName("Create Compat Recipes Tests")
+class CreateCompatRecipesTest {
+
+    private static final int SHARDS_PER_DIAMOND = 9;
+    private static final String SHARD_ITEM = "custom_ore_gen:diamondshard";
+    private static final String DIAMOND_ITEM = "minecraft:diamond";
+
+    private static final String MIXING_RECIPE = "/data/create/recipe/mixing/diamond_shard_to_diamond.json";
+    private static final String CRUSHING_RECIPE = "/data/create/recipe/crushing/diamond_to_shards.json";
+    private static final String MILLING_RECIPE = "/data/create/recipe/milling/diamond_to_shards.json";
+    private static final String CRAFTING_RECIPE = "/data/custom_ore_gen/recipe/diamondshardtodiamond.json";
+
+    private static JsonObject loadRecipe(String path) {
+        InputStream stream = CreateCompatRecipesTest.class.getResourceAsStream(path);
+        assertNotNull(stream, "Recipe resource missing from classpath: " + path);
+        return JsonParser.parseReader(new InputStreamReader(stream, StandardCharsets.UTF_8)).getAsJsonObject();
+    }
+
+    private static double expectedShardYield(JsonObject recipe) {
+        double yield = 0.0;
+        for (JsonElement element : recipe.getAsJsonArray("results")) {
+            JsonObject result = element.getAsJsonObject();
+            if (!result.has("id") || !SHARD_ITEM.equals(result.get("id").getAsString())) {
+                continue;
+            }
+            int count = result.has("count") ? result.get("count").getAsInt() : 1;
+            double chance = result.has("chance") ? result.get("chance").getAsDouble() : 1.0;
+            yield += count * chance;
+        }
+        return yield;
+    }
+
+    @Test
+    @DisplayName("Mixing recipe consumes exactly 9 shards as 9 single-item ingredients")
+    void testMixingRecipe_ShouldConsumeNineShardsViaNineEntries() {
+        JsonObject recipe = loadRecipe(MIXING_RECIPE);
+        assertEquals("create:mixing", recipe.get("type").getAsString());
+
+        JsonArray ingredients = recipe.getAsJsonArray("ingredients");
+        assertNotNull(ingredients, "Mixing recipe must declare ingredients");
+        assertEquals(SHARDS_PER_DIAMOND, ingredients.size(),
+                "Mixing recipe must list the shard 9 times (Create ignores 'count' on item ingredients)");
+
+        for (JsonElement element : ingredients) {
+            JsonObject ingredient = element.getAsJsonObject();
+            assertEquals(SHARD_ITEM, ingredient.get("item").getAsString(),
+                    "Every mixing ingredient must be a diamond shard");
+            assertFalse(ingredient.has("count"),
+                    "Never use 'count' on Create item ingredients: it is silently ignored (dupe exploit)");
+        }
+    }
+
+    @Test
+    @DisplayName("Mixing recipe outputs exactly 1 diamond")
+    void testMixingRecipe_ShouldOutputOneDiamond() {
+        JsonObject recipe = loadRecipe(MIXING_RECIPE);
+        JsonArray results = recipe.getAsJsonArray("results");
+        assertEquals(1, results.size(), "Mixing recipe must have a single result");
+        JsonObject result = results.get(0).getAsJsonObject();
+        assertEquals(DIAMOND_ITEM, result.get("id").getAsString());
+        assertEquals(1, result.get("count").getAsInt(), "9 shards must yield exactly 1 diamond");
+    }
+
+    @Test
+    @DisplayName("Vanilla crafting recipe uses 9 shards for 1 diamond")
+    void testCraftingRecipe_ShouldUseNineShards() {
+        JsonObject recipe = loadRecipe(CRAFTING_RECIPE);
+        assertEquals("minecraft:crafting_shaped", recipe.get("type").getAsString());
+
+        JsonObject key = recipe.getAsJsonObject("key");
+        assertEquals(SHARD_ITEM, key.getAsJsonObject("a").get("item").getAsString());
+
+        int shardSlots = 0;
+        for (JsonElement row : recipe.getAsJsonArray("pattern")) {
+            for (char c : row.getAsString().toCharArray()) {
+                if (c == 'a') {
+                    shardSlots++;
+                }
+            }
+        }
+        assertEquals(SHARDS_PER_DIAMOND, shardSlots, "Crafting pattern must contain 9 shard slots");
+
+        JsonObject result = recipe.getAsJsonObject("result");
+        assertEquals(DIAMOND_ITEM, result.get("id").getAsString());
+        assertEquals(1, result.get("count").getAsInt());
+    }
+
+    @Test
+    @DisplayName("Crushing a diamond yields less than 9 shards on average (no dupe loop)")
+    void testCrushingRecipe_ShouldStayBelowDupeThreshold() {
+        double yield = expectedShardYield(loadRecipe(CRUSHING_RECIPE));
+        assertTrue(yield > 0, "Crushing recipe must produce shards");
+        assertTrue(yield < SHARDS_PER_DIAMOND,
+                "Crushing yield (" + yield + ") must stay below " + SHARDS_PER_DIAMOND
+                        + " shards per diamond or the mixer/crusher cycle duplicates diamonds");
+    }
+
+    @Test
+    @DisplayName("Milling a diamond yields less than 9 shards on average (no dupe loop)")
+    void testMillingRecipe_ShouldStayBelowDupeThreshold() {
+        double yield = expectedShardYield(loadRecipe(MILLING_RECIPE));
+        assertTrue(yield > 0, "Milling recipe must produce shards");
+        assertTrue(yield < SHARDS_PER_DIAMOND,
+                "Milling yield (" + yield + ") must stay below " + SHARDS_PER_DIAMOND
+                        + " shards per diamond or the mixer/millstone cycle duplicates diamonds");
+    }
+}