UrlEncodedPairParser creates wrong params hash with nested attributes in arrays

In the following arguments, you are treating email[to_new_contacts] like an array with []

&email[to_new_contacts][][contact_attributes][first_name]=first

&email[to_new_contacts][][contact_attributes][middle_name]=middle

&email[to_new_contacts][][contact_attributes][first_name]=first2

&email[to_new_contacts][][contact_attributes][middle_name]=middle2

However, in these arguments, you are treating email[to_new_contacts] like a hash by indexing it with "relationship"

&email[to_new_contacts][relationship]=friend

&email[to_new_contacts][relationship]=friend2

You probably just want to use a hash like this:

&email[to_new_contacts][friend][contact_attributes][first_name]=first

&email[to_new_contacts][friend][contact_attributes][middle_name]=middle

&email[to_new_contacts][friend2][contact_attributes][first_name]=first2

&email[to_new_contacts][friend2][contact_attributes][middle_name]=middle2

&email[to_new_contacts][relationship]=friend

&email[to_new_contacts][relationship]=friend2

Which will create these params:

{"email"=>
  {"to_new_contacts"=>
    {"friend2"=>
      {"contact_attributes"=>
        {"first_name"=>"first2", "middle_name"=>"middle2"}},
     "relationship"=>"friend",
     "friend"=>
      {"contact_attributes"=>
        {"first_name"=>"first", "middle_name"=>"middle"}}}}}

A patch which (mostly) fixes this problem is available here http://www.vector-seven.com/2008...

I'm using it in production with minor tweaks to the form helpers and I have had very few issues.

Also an idea to compact! the arrays which are returned as they often contain nils.

I have attached a view template that demonstrates the problem. You have to set up a simple controller and an action in routes.rb for it work, but that takes two minutes.

The form conctains the following fields:

When you submit the form normally, Rails groups the values proper in params[] like this:

Parameters: {"commit"=>"Subtmit", "rule"=>{"condition_list"=>[{"text"=>"text1", "value"=>"value1"}, {"text"=>"text2", "value"=>"value2"}, {"text"=>"text3", "value"=>"value3"}]}}

But when you use button_to_remove to submit via Ajax, the values are no longer properly grouped:

Parameters: {"commit"=>"Submit", "authenticity_token"=>"ZW+GHWqfHCpp4rDp67xYHn2a7iOJlbgLg1YYYVZJb9o=", "id"=>"1", "rule"=>{"condition_list"=>[{"text"=>"text1"}, {"text"=>"text2"}, {"text"=>"text3", "value"=>"value1"}, {"value"=>"value2"}, {"value"=>"value3"}]}}

This issue has been automatically marked as stale because it has not been commented on for at least three months.

The resources of the Rails core team are limited, and so we are asking for your help. If you can still reproduce this error on the 3-0-stable branch or on master, please reply with all of the information you have about it and add "[state:open]" to your comment. This will reopen the ticket for review. Likewise, if you feel that this is a very important feature for Rails to include, please reply with your explanation so we can consider it.

Thank you for all your contributions, and we hope you will understand this step to focus our efforts where they are most helpful.