Program: 187468
Project: 187468
Buggy source:
public boolean handlePlayerInteraction(EntityHuman entityhuman,EnumHand enumhand,ItemStack itemStack){
  if (super.handlePlayerInteraction(entityhuman,enumhand,itemStack)) {
    return true;
  }
  if (getOwner().equals(entityhuman)) {
    if (itemStack != null) {
      MyPetApi.getLogger().info("String_Node_Str" + itemStack.getTag().toString());
      if (canUseItem()) {
        if (itemStack.getItem() instanceof ItemDye && ((ItemDye)itemStack.getItem()).d().ordinal() != getMyPet().getCollarColor().ordinal()) {
          if (getOwner().getPlayer().isSneaking()) {
            getMyPet().setCollarColor(DyeColor.values()[((ItemDye)itemStack.getItem()).d().ordinal()]);
            if (!entityhuman.abilities.canInstantlyBuild) {
              itemStack.subtract(1);
              if (itemStack.getCount() <= 0) {
                entityhuman.inventory.setItem(entityhuman.inventory.itemInHandIndex,ItemStack.a);
              }
            }
            return true;
          }
 else {
            this.datawatcher.set(collarWatcher,0);
            updateVisuals();
            return false;
          }
        }
 else         if (Configuration.MyPet.Wolf.GROW_UP_ITEM.compare(itemStack) && getMyPet().isBaby() && getOwner().getPlayer().isSneaking()) {
          if (!entityhuman.abilities.canInstantlyBuild) {
            itemStack.subtract(1);
            if (itemStack.getCount() <= 0) {
              entityhuman.inventory.setItem(entityhuman.inventory.itemInHandIndex,ItemStack.a);
            }
          }
          getMyPet().setBaby(false);
          return true;
        }
      }
    }
  }
  return false;
}

Fixed version (ground truth):
public boolean handlePlayerInteraction(EntityHuman entityhuman,EnumHand enumhand,ItemStack itemStack){
  if (super.handlePlayerInteraction(entityhuman,enumhand,itemStack)) {
    return true;
  }
  if (getOwner().equals(entityhuman)) {
    if (itemStack != null && itemStack.getItem() != Items.AIR) {
      if (canUseItem()) {
        if (itemStack.getItem() instanceof ItemDye && ((ItemDye)itemStack.getItem()).d().ordinal() != getMyPet().getCollarColor().ordinal()) {
          if (getOwner().getPlayer().isSneaking()) {
            getMyPet().setCollarColor(DyeColor.values()[((ItemDye)itemStack.getItem()).d().ordinal()]);
            if (!entityhuman.abilities.canInstantlyBuild) {
              itemStack.subtract(1);
              if (itemStack.getCount() <= 0) {
                entityhuman.inventory.setItem(entityhuman.inventory.itemInHandIndex,ItemStack.a);
              }
            }
            return true;
          }
 else {
            this.datawatcher.set(collarWatcher,0);
            updateVisuals();
            return false;
          }
        }
 else         if (Configuration.MyPet.Wolf.GROW_UP_ITEM.compare(itemStack) && getMyPet().isBaby() && getOwner().getPlayer().isSneaking()) {
          if (!entityhuman.abilities.canInstantlyBuild) {
            itemStack.subtract(1);
            if (itemStack.getCount() <= 0) {
              entityhuman.inventory.setItem(entityhuman.inventory.itemInHandIndex,ItemStack.a);
            }
          }
          getMyPet().setBaby(false);
          return true;
        }
      }
    }
  }
  return false;
}