position not updated with move_higher or move_lover

[nortcele]

I have a strange behavior with acts_as_list, Rails 3.1 and Ruby 1.9.2p290.

Steps to reproduce

• Create a test application
  rails new asl_test
  cd asl_test
• Add

gem 'acts_as_list', :git => 'https://github.com/swanandp/acts_as_list.git'

in gemfile.

• Update gems

bundle update

• Generate a model
  rails generate model Hand side:string
• Generate a second model
  rails generate model Finger position:integer name:string hand_id:integer
• Migrate the db
  bundle exec rake db:migrate
• Modify the hand model
  class Hand < ActiveRecord::Base
  has_many :fingers
  end
• Modify the finger model
  class Finger < ActiveRecord::Base
  belongs_to :hand
  acts_as_list :scope => :hand
  end
• Now go to the console
  rails console
• Create a hand
  lefty = Hand.create(:side => "left")
• Add some fingers
  lefty.fingers.create(:name => "thumb")
  lefty.fingers.create(:name => "index")
  lefty.fingers.create(:name => "ring")
  lefty.fingers.create(:name => "middle")
  lefty.fingers.create(:name => "baby")

Let's see the fingers
lefty.fingers.each do |finger| puts "#{finger.position}: #{finger.name}" end

That gives what was inserted.
1: thumb
2: index
3: ring
4: middle
5: baby

But one finger is not at the good place so try to correct that.
lefty.fingers[3].move_lower

Let's see the fingers now
lefty.fingers.each do |finger| puts "#{finger.position}: #{finger.name}" end

The result is not what I expected
1: thumb
2: index
3: ring
5: middle
5: baby

I don't know why middle and ring where not interverted and why there are two fingers whose position is 5.

[nerab]

I put this into a unit test: https://github.com/nerab/acts_as_list_issue_23

My test passes with Rails 3.1.3 on Ruby 1.8.7.

[swanandp]

This seems like a serious bug. I am on it.

[jschairb]

Is there any status on this?

[swanandp]

Unfortunately, not yet. If anyone is willing to send pull request, I'll be more than glad to merge it.

[splattael]

I've added a test case which is passing on 1.8.7 and 1.9.2.

[swanandp]

This might be a data caching issue. I tried the same thing, seems to work w/o issue.
Also, test_reordering and test_move_to_bottom_with_next_to_last_item do cover this case.

[jschairb]

I've spent a few minutes trying to write a failing test with the existing test harnesses, but I can verify that the problem exists with the sqlite3 and PostgreSQL adapters. I'm continuing to investigate however I think the problem lies with #bottom_item.

[swanandp]

@jschairb When you verified the problem, did you actually check DB values? i.e. lefty.reload.fingers.each { |finger| puts "#{finger.position}: #{finger.name}" } or something to that effect? But in any case, can you create gist with that test case and point us to it? I tested it too, and my results are similar to @splattael's.