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fields_for ignores supplied collection (ActiveRecord::Relation)

#5795

When supplying a collection for use with the fields_for helper method, it will only be used if the object is an Array. It should also work with an ActiveRecord::Relation.

Example

See the example, taken from http://railsapi.com/doc/rails-v3.0.0/classes/ActionView/Helpers/For...)

edit.html.erb

<%= form_for @person do |person_form| %>
    ...
    <%= person_form.fields_for :projects, @active_projects do |project_fields| %>
      Name: <%= project_fields.text_field :name %>
    <% end %>
<% end %>

The @active_projects variable is only used when it is forced into an Array:

people_controller.rb

  def edit
    ...
    # when using this scenario, the @active_projects collection is not used
    @active_projects = @person.projects.where(:active => true)

    # when forcing the conversion to an array, @active_projects is used
    @active_projects = @person.projects.where(:active => true).all
  end

Note: when the @active_projects variable is not used, the default @person.projects association is used.

Reported by Nigel Ramsay · October 12th, 2010 @ 11:26 PM

State: resolved
Milestone: 3.0.2
Assigned to: José Valim José Valim
Importance: Low

Activity

  1. Nigel Ramsay
    Nigel Ramsay
    • Tag changed from fields_for, form_helper, relation to 3.0.0, fields_for, form_helper, relation

    October 12th, 2010 @ 11:30 PM

  2. Nigel Ramsay
    Nigel Ramsay

    This problem originates in form_helper.rb:1159:

    case record_or_name_or_array
  when String, Symbol
    if nested_attributes_association?(record_or_name_or_array)
      return fields_for_with_nested_attributes(record_or_name_or_array, args, block)
    else
      name = "#{object_name}#{index}[#{record_or_name_or_array}]"
    end
  when Array # 1159
    object = record_or_name_or_array.last
    name = "#{object_name}#{index}[#{ActiveModel::Naming.singular(object)}]"
    args.unshift(object)
  else
    object = record_or_name_or_array
    name = "#{object_name}#{index}[#{ActiveModel::Naming.singular(object)}]"
    args.unshift(object)
  end

    rather than checking for an Array class, we should really be checking for an "array-like" class.

    October 12th, 2010 @ 11:41 PM

  3. Nigel Ramsay
    Nigel Ramsay

    Perhaps the replacement check should be similar to that used in partials.rb:302

      if @object.respond_to?(:to_ary)

    October 13th, 2010 @ 12:06 AM

  4. Ryan Bigg
    Ryan Bigg
    • State changed from new to incomplete
    • Importance changed from to Low

    Please submit a failing test case for this issue as per this guide: http://guides.rubyonrails.org/contributing_to_rails.html

    October 13th, 2010 @ 06:27 AM

  5. Ryan Bigg
    Ryan Bigg
    • Tag cleared.

    Automatic cleanup of spam.

    October 19th, 2010 @ 08:27 AM

  6. Neeraj Singh
    Neeraj Singh
    • State changed from incomplete to open
    • Milestone set to 3.0.2
    • Assigned user changed from Michael Koziarski to Neeraj Singh

    Code fix is here. I tested it and it works. However writing writing the test is taking some time. Hopefully will finish the test tomorrow. I will submit a proper patch when test is ready. In the meantime here is the code change.

            def fields_for_with_nested_attributes(association_name, args, block)
          name = "#{object_name}[#{association_name}_attributes]"
          options = args.extract_options!
          association = args.shift
          association = convert_to_model(association)

          debugger

          if association.respond_to?(:persisted?)
            association = [association] if @object.send(association_name).is_a?(Array)
          #elsif !association.is_a?(Array)
          elsif !association.respond_to?(:to_ary)
            association = @object.send(association_name)
          end

          #if association.is_a?(Array)
          if association.respond_to?(:to_ary)
            explicit_child_index = options[:child_index]
            output = ActiveSupport::SafeBuffer.new
            association.each do |child|
              output << fields_for_nested_model("#{name}[#{explicit_child_index || nested_child_index(name)}]", child, options, block)
            end
            output
          elsif association
            fields_for_nested_model(name, association, options, block)
          end
        end

    November 11th, 2010 @ 05:53 AM

  7. Neeraj Singh
    Neeraj Singh
    • Assigned user changed from Neeraj Singh to José Valim
    • Tag set to patched

    Attached is code patch with test.

    November 11th, 2010 @ 03:08 PM

  8. Repository
    Repository
    • State changed from open to resolved

    November 11th, 2010 @ 04:19 PM

  9. Repository
    Repository

    November 11th, 2010 @ 04:21 PM