Rails3 (with Ruby 1.9.1) problem when sorting a list

Hi,

Here is a sample of the list HTML:

<ul id="sort"> 
   <li id='menu_item_1'>home</li> 
   <li id='menu_item_3'>info</li> 
   <li id='menu_item_2'>portfolio</li>
</ul>

Here is the javascript from my application.js that handles the sorting and handles the request:

$(function() {
    $("#sort").sortable({
        update : function (event, ui) {
        $.ajax({
            type: "PUT",
        url: "/pages",
        data: $(this).sortable("serialize")
        });
    }
    });
});

Now here is my problem. when I use 1.8.7 with RVM there is no problem. When I drag an item from the list around I get a nice PUT request to my controller. Here is some output in the console:

Started PUT "/pages" for 127.0.0.1 at 2010-03-25 08:47:33
  Processing by PagesController#update as */*
  Parameters: {"menu_item"=>[{"2"=>nil}, {"1"=>nil}, {"3"=>nil}]}

But when I switch with RVM to Ruby 1.9.1 and change nothing in the code, I get the following exception in the console:

Started PUT "/pages" for 127.0.0.1 at 2010-03-25 08:44:09

NoMethodError (undefined method `each' for "3":String):

Rendered /Users/jelle/.rvm/gems/ruby-1.9.1-p378/gems/actionpack-3.0.0.beta/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.3ms)
Rendered /Users/jelle/.rvm/gems/ruby-1.9.1-p378/gems/actionpack-3.0.0.beta/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (3.9ms)
Rendered /Users/jelle/.rvm/gems/ruby-1.9.1-p378/gems/actionpack-3.0.0.beta/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within /Users/jelle/.rvm/gems/ruby-1.9.1-p378/gems/actionpack-3.0.0.beta/lib/action_dispatch/middleware/templates/rescues/layout.erb (17.6ms)

No other trace is provided... So very hard for me to debug.

What I do know is that the exception that is raised is very logic because in Ruby 1.9 the String class isn't an enumerator so it loses the .each method. (I wrote an article in my blog).

Hope someone can help me with this bug, or at least point out where I have to look to create a patch :)

Thnx in advance!

Jelle
www.fousa.be