Fixed dupe bug in ItemMatcher and made hasRoom not modify the inventory contents.

src/main/java/com/alttd/playershops/utils/InventoryUtils.java

@@ -109,17 +109,20 @@ public class InventoryUtils {
         if (itemStack.getAmount() <= 0)
             return true;
 
-        int overflow = addItem(inventory, itemStack);
+        int remaining = itemStack.getAmount();
 
-        //revert back if inventory cannot hold all of the items
-        if (overflow > 0) {
-            ItemStack revert = itemStack.clone();
-            revert.setAmount(revert.getAmount() - overflow);
-            InventoryUtils.removeItem(inventory, revert);
-            return false;
+        for (ItemStack stack : inventory.getStorageContents()) {
+            if (stack == null || stack.getType().isAir()) {
+                remaining -= itemStack.getMaxStackSize();
+            } else if (stack.isSimilar(itemStack)) {
+                remaining -= stack.getMaxStackSize() - stack.getAmount();
             }
-        removeItem(inventory, itemStack);
+
+            if (remaining <= 0)
                 return true;
         }
 
+        return false;
+    }
+
 }

src/main/java/com/alttd/playershops/utils/ItemMatcher.java

@@ -266,8 +266,8 @@ public class ItemMatcher {
                                 return false; // not the same color
 
                             // Do we need all of the above checks inside the shulker?
-                            if (Arrays.equals(shulkerBox1.getInventory().getContents(), shulkerBox2.getInventory().getContents()))
-                                return true; // same content
+                            // same content if true
+                            return Arrays.equals(shulkerBox1.getInventory().getContents(), shulkerBox2.getInventory().getContents());
                         }
                     }
                     return true;
@@ -295,7 +295,7 @@ public class ItemMatcher {
         }
 
         if (item1 == null || item2 == null) {
-            return true;
+            return false;
         }
 
         if (!item1.getType().equals(item2.getType())) {
@@ -310,7 +310,7 @@ public class ItemMatcher {
             return metaMatches(item1, item2);
         }
 
-        return !item1.hasItemMeta() && !item1.hasItemMeta();
+        return !item1.hasItemMeta() && !item2.hasItemMeta();
     }
 
     protected static boolean metaMatches(ItemStack item1, ItemStack item2) {