Is Acts_as_list's 'last?' method not working as intended or am i making a mistake?

So I am using acts_as_list in my current rails project. And I run into the following odd behavior:

When i remove an item from the list (item.remove_from_list) it correctly sets the position column of this item to nil and updates the position values of the other list items.

However, when I call last? on the "last" item in the list (e.g开发者_运维百科. the one with the highest position number) it returns false. In fact, every item in the list will return false to the last? method. I suddenly seem to have lost my last? item!

What's going wrong here?

Kind regards, Erwin

---

In acts_as_list, the last? method is added to each ActiveRecord instance:

# Return +true+ if this object is the last in the list.
def last?
  return false unless in_list?
  self.send(position_column) == bottom_position_in_list
end

First it checks if the object is in the list. Here's the method:

# Test if this record is in a list
def in_list?
  !send(position_column).nil?
end

So I would check the position_column of the object you believe to be last in the list to see if it is non-nil. Do this before and after you remove an object from the list.