Rails core - May 2009 - strange behaviour in ActiveRecord transaction

Hi,
I''m using an ActiveRecord transaction in a Rails app,
with Rails 2.3.2, Windows (Vista), MySQL 5.0.
No exception is being raised in the transaction, but one of the
changes made during the transaction is reverted
as the transaction finishes, whilst the other changes are preserved.
(Using "puts ..." shows the values displayed in comments in the code
below.) The same reversion is consistently happening.
The code is like:

------------------------
def swap(other)

  self_number=self.number    #==1
  other_number=other.number  #==2

  ActiveRecordModel.transaction do

    version=Version.find_by_kind(self.kind)
    #version.ver_num==30

    self.number=other_number
    other.number=self_number
    self.save
    other.save

    version.ver_num+=1
    version.save

    #self.number==2
    #other.number==1
    #version.ver_num==31
  end

  #self.number==1    ***Reverted!
  #other.number==1
  #version.ver_num==31

end
------------------------

Also, I''ve tried reversing the order of work on self and other
in the transaction, but it''s still just self.number that reverts. Any
ideas?

Solved.
This was not an issue with ActiveRecord/Rails.
(I had to use "self.number=" instead of "number=". Using
"number="
wasn''t actually calling the function "number=",
but I presume was creating a local variable "number" instead.)

I just noticed that in the code sample I submitted, I actually
wrote "self.number=". In my original code I had "number=".