Don't set smelt stacks to above item's max stack size

Changelog.txt

@@ -1,4 +1,5 @@
 Version 2.1.175
+    Fixed a bug where mcMMO would occasionally give a 65 item stack from a double smelt on a furnace
 
 Version 2.1.174
     Some legacy color codes in our locale file were swapped to &-code equivalents (thanks ViaSnake)

src/main/java/com/gmail/nossr50/listeners/InventoryListener.java

@@ -116,7 +116,8 @@ public class InventoryListener implements Listener {
 
                 //Profile doesn't exist
                 if(offlineProfile != null) {
-                    event.setResult(offlineProfile.getSmeltingManager().smeltProcessing(smelting, event.getResult()));
+                    //Process smelting
+                    offlineProfile.getSmeltingManager().smeltProcessing(event);
                 }
             }
         }

src/main/java/com/gmail/nossr50/skills/smelting/SmeltingManager.java

@@ -12,7 +12,9 @@ import com.gmail.nossr50.util.random.RandomChanceUtil;
 import com.gmail.nossr50.util.skills.RankUtils;
 import com.gmail.nossr50.util.skills.SkillActivationType;
 import org.bukkit.event.inventory.FurnaceBurnEvent;
+import org.bukkit.event.inventory.FurnaceSmeltEvent;
 import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
 
 public class SmeltingManager extends SkillManager {
     public SmeltingManager(McMMOPlayer mcMMOPlayer) {
@@ -108,19 +110,29 @@ public class SmeltingManager extends SkillManager {
         }
     }
 
-    public ItemStack smeltProcessing(ItemStack smelting, ItemStack result) {
+    public void smeltProcessing(@NotNull FurnaceSmeltEvent furnaceSmeltEvent) {
+        ItemStack sourceItemStack = furnaceSmeltEvent.getSource();
+        ItemStack resultItemStack = furnaceSmeltEvent.getResult();
 
-        applyXpGain(Smelting.getResourceXp(smelting), XPGainReason.PVE, XPGainSource.PASSIVE);
+        applyXpGain(Smelting.getResourceXp(sourceItemStack), XPGainReason.PVE, XPGainSource.PASSIVE); //Add XP
+        int itemLimit = resultItemStack.getMaxStackSize();
 
-        if (Config.getInstance().getDoubleDropsEnabled(PrimarySkillType.SMELTING, result.getType())
-                && isSecondSmeltSuccessful() && result.getAmount() < 64) {
-            ItemStack newResult = result.clone();
+        processDoubleSmelt(furnaceSmeltEvent, resultItemStack, itemLimit);
+    }
 
-            newResult.setAmount(result.getAmount() + 1);
-            return newResult;
-        }
+    private void processDoubleSmelt(@NotNull FurnaceSmeltEvent furnaceSmeltEvent, @NotNull ItemStack resultItemStack, int itemLimit) {
+        //TODO: Permission check work around, could store it as NBT on the furnace
+        //We don't do permission checks because this can be for an offline player and Bukkit has nothing to grab permissions for offline players
 
-        return result;
+        //Process double smelt
+        if (Config.getInstance().getDoubleDropsEnabled(PrimarySkillType.SMELTING, resultItemStack.getType())
+                && resultItemStack.getAmount() < itemLimit
+                && isSecondSmeltSuccessful()) {
+
+            ItemStack newResult = resultItemStack.clone();
+            newResult.setAmount(Math.min(resultItemStack.getAmount() + 1, itemLimit)); //Don't go over max stack limits
+            furnaceSmeltEvent.setResult(newResult);
+        }
     }
 
     public int vanillaXPBoost(int experience) {