Program: 89052
Project: 89052
Buggy source:
/** 
 * Handles the given inventory event using the default behavior for the given inventory type.
 * @param event - inventory click event.
 * @param response - block response detailing how to process the inventory.
 */
public void processInventory(InventoryClickEvent event,BlockResponse response){
  if (!BlockResponse.isSuccessful(response))   throw new IllegalArgumentException("String_Node_Str");
  if (!response.hasDefaultBehavior())   throw new IllegalArgumentException("String_Node_Str");
  Player player=(Player)event.getWhoClicked();
  ItemStack toCraft=response.getOverridableCurrentItem(event);
  InventoryType type=response.getDefaultBehavior();
  if (player.hasPermission(response.getPermission())) {
    return;
  }
  Configuration config=getConfiguration(player);
  if (type == InventoryType.BREWING) {
    if (config == null) {
      if (debugger != null)       debugger.printDebug(this,"String_Node_Str",player.getName(),toCraft);
      return;
    }
    RewardableAction potionFuture=potionItemReward(config);
    ItemTree simpleTree=config.getActionReward(response.getActionType());
    PotionTree complexTree=config.getComplexReward(response.getActionType());
    if (simpleTree != null)     handleInventory(event,response,simpleTree,potionFuture,true);
 else     debugger.printDebug(this,"String_Node_Str",response.getActionType());
    if (complexTree != null)     handleInventory(event,response,complexTree.getItemQueryAdaptor(),potionFuture,true);
 else     debugger.printDebug(this,"String_Node_Str",response.getActionType());
  }
 else {
    if (config != null) {
      RewardableAction itemFuture=genericItemReward(config);
      ItemTree craftingTree=config.getActionReward(response.getActionType());
      handleInventory(event,response,craftingTree,itemFuture,false);
    }
 else     if (debugger != null) {
      debugger.printDebug(this,"String_Node_Str",player.getName(),toCraft);
    }
  }
}

Fixed version (ground truth):
/** 
 * Handles the given inventory event using the default behavior for the given inventory type.
 * @param event - inventory click event.
 * @param response - block response detailing how to process the inventory.
 */
public void processInventory(InventoryClickEvent event,BlockResponse response){
  if (!BlockResponse.isSuccessful(response))   throw new IllegalArgumentException("String_Node_Str");
  if (!response.hasDefaultBehavior())   throw new IllegalArgumentException("String_Node_Str");
  Player player=(Player)event.getWhoClicked();
  ItemStack toCraft=response.getOverridableCurrentItem(event);
  InventoryType type=response.getDefaultBehavior();
  if (!player.hasPermission(response.getPermission())) {
    debugger.printDebug(this,"String_Node_Str",response.getPermission(),response.getActionType());
    return;
  }
  Configuration config=getConfiguration(player);
  if (type == InventoryType.BREWING) {
    if (config == null) {
      if (debugger != null)       debugger.printDebug(this,"String_Node_Str",player.getName(),toCraft);
      return;
    }
    RewardableAction potionFuture=potionItemReward(config);
    ItemTree simpleTree=config.getActionReward(response.getActionType());
    PotionTree complexTree=config.getComplexReward(response.getActionType());
    if (simpleTree != null)     handleInventory(event,response,simpleTree,potionFuture,true);
 else     debugger.printDebug(this,"String_Node_Str",response.getActionType());
    if (complexTree != null)     handleInventory(event,response,complexTree.getItemQueryAdaptor(),potionFuture,true);
 else     debugger.printDebug(this,"String_Node_Str",response.getActionType());
  }
 else {
    boolean partial=(type == InventoryType.FURNACE);
    if (config != null) {
      RewardableAction itemFuture=genericItemReward(config);
      ItemTree craftingTree=config.getActionReward(response.getActionType());
      handleInventory(event,response,craftingTree,itemFuture,partial);
    }
 else     if (debugger != null) {
      debugger.printDebug(this,"String_Node_Str",player.getName(),toCraft);
    }
  }
}