Question

I haven’t used rails since version 1.2 or so and a few things have changed. I have an issue where I am trying to save an empty model to get validation errors on attributes using :validates_presence_of and instead I am getting the error ‘can’t convert HashWithIndifferentAccess into String’. I will attempt to simplify my code to get the point across as tersely as possible…

my model:

class Project < ActiveRecord::Base

    validates_presence_of :title, :description
    validates_uniqueness_of :title

    has_one :address

    accepts_nested_attributes_for :address, :allow_destroy => true
end

Child model:

class Address < ActiveRecord::Base
    validates_presence_of :title, :street
    belongs_to :project
end

controller:

class ProjectsController < ApplicationController
    def create
        @project = Project.new(params[:project])
        if @project.save
            flash[:notice] = @project.title + ' successfully created'
            redirect_to projects_path
        else
            render :action => 'new'
        end
    end
end

view:

<%= error_messages_for 'project' %>
<% form_for @project do |f| %>
<table width="100%" cellpadding="3" cellspacing="0">
    <tr>
        <td class="adminlabel">
            <label for="Title">Title</label>
        </td>
        <td class="adminbody">
            <%= f.text_field :title %>
        </td>
    </tr>   
    .....
    <% f.fields_for :address do |address| %>
    ....

This code adds and updates just fine as long as I fill in all the required fields, if I leave any blank I get the error mentioned above, not the most graceful way of alerting users there is an issue 😉

Request params:
{“commit”=>”Save”,
“project”=>{“title”=>””,
“notes”=>””,
“description”=>””,
“address_attributes”=>{“city”=>””,
“zip”=>””,
“title”=>””,
“country”=>””,
“suite”=>””,
“street”=>””,
“state”=>””}},
“authenticity_token”=>”iNPQZrf/oBv22vaI0toTGhknwx0aAU3BSvnIh6qgYQ8=”}

I have been searching for days and am at my wits end, if anyone can shed a little light on this for me I would greatly appreciate it.

Thanks in advance!

Brendan

PS – the stack trace as requested:

.../app/controllers/projects_controller.rb:27:in `+'  
.../app/controllers/projects_controller.rb:27:in `create'  
../actionpack-2.3.4/lib/action_controller/base.rb:1331:in `send'  
../actionpack-2.3.4/lib/action_controller/base.rb:1331:in `perform_action_without_filters'  
../actionpack-2.3.4/lib/action_controller/filters.rb:617:in `call_filters'  
../actionpack-2.3.4/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark'  
../actionpack-2.3.4/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'  
../activesupport-2.3.4/lib/active_support/core_ext/benchmark.rb:17:in `ms'  
../activesupport-2.3.4/lib/active_support/core_ext/benchmark.rb:10:in `realtime'  
../activesupport-2.3.4/lib/active_support/core_ext/benchmark.rb:17:in `ms'  
../actionpack-2.3.4/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'  
../actionpack-2.3.4/lib/action_controller/rescue.rb:160:in `perform_action_without_flash'  
../actionpack-2.3.4/lib/action_controller/flash.rb:146:in `perform_action'  
../actionpack-2.3.4/lib/action_controller/base.rb:532:in `send'  
../actionpack-2.3.4/lib/action_controller/base.rb:532:in `process_without_filters'  
../actionpack-2.3.4/lib/action_controller/filters.rb:606:in `process'  
../actionpack-2.3.4/lib/action_controller/base.rb:391:in `process'  
../actionpack-2.3.4/lib/action_controller/base.rb:386:in `call'  
../actionpack-2.3.4/lib/action_controller/routing/route_set.rb:437:in `call'  
../actionpack-2.3.4/lib/action_controller/dispatcher.rb:87:in `dispatch'  
../actionpack-2.3.4/lib/action_controller/dispatcher.rb:121:in `_call'  
../actionpack-2.3.4/lib/action_controller/dispatcher.rb:130:in `build_middleware_stack'   
../activerecord-2.3.4/lib/active_record/query_cache.rb:29:in `call'  
../activerecord-2.3.4/lib/active_record/query_cache.rb:29:in `call'  
../activerecord-2.3.4/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache'  
..activerecord-2.3.4/lib/active_record/query_cache.rb:9:in `cache'   
../activerecord-2.3.4/lib/active_record/query_cache.rb:28:in `call'  
../activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:361:in `call'  
../rack-1.0.1/lib/rack/head.rb:9:in `call'  
../rack-1.0.1/lib/rack/methodoverride.rb:24:in `call'  
../actionpack-2.3.4/lib/action_controller/params_parser.rb:15:in `call'  
../actionpack-2.3.4/lib/action_controller/session/cookie_store.rb:93:in `call'  
../actionpack-2.3.4/lib/action_controller/failsafe.rb:26:in `call'  
../rack-1.0.1/lib/rack/lock.rb:11:in `call'  
../rack-1.0.1/lib/rack/lock.rb:11:in `synchronize'  
../rack-1.0.1/lib/rack/lock.rb:11:in `call'  
../actionpack-2.3.4/lib/action_controller/dispatcher.rb:114:in `call'  
../actionpack-2.3.4/lib/action_controller/reloader.rb:34:in `run'  
../actionpack-2.3.4/lib/action_controller/dispatcher.rb:108:in `call'  
../rails-2.3.4/lib/rails/rack/static.rb:31:in `call'  
../rack-1.0.1/lib/rack/urlmap.rb:46:in `call'  
../rack-1.0.1/lib/rack/urlmap.rb:40:in `each'  
../rack-1.0.1/lib/rack/urlmap.rb:40:in `call'  
../rails-2.3.4/lib/rails/rack/log_tailer.rb:17:in `call'  
../rack-1.0.1/lib/rack/content_length.rb:13:in `call'  
../rack-1.0.1/lib/rack/chunked.rb:15:in `call'  
../rack-1.0.1/lib/rack/handler/mongrel.rb:64:in `process'
..... etc.

A bit lengthy, sorry 😉

Answer 1

Try adding

@project.address.build

to your controller. You need to instantiate the address object.