Ruby on Rails

On Sep 9, 2013, at 5:16 PM, Brett Pontarelli <brett@paperyfrog.com> wrote:

> Below is an example of the error I encountered in my project today and after a great deal of searching I realized the problem to be that the *_attributes needs to be an array! My first question is, is there a use for *_attributes={} and is there something I'm missing to make it work in that case? If not, then what should the behavior be? Should it be allowed and instead create one record (a letter for example)? Thanks.
>
> Setup a simple rails app:
>
> class Word < ActiveRecord::Base
> has_many :letters, dependent: :destroy

Since you told it there would be many letters in the word, it only seems to make sense that 'letters_attributes' would an Array, even if it only has one item in it.

> accepts_nested_attributes_for :letters
> end
>
> class Letter < ActiveRecord::Base
> belongs_to :word
> end
>
> This works just fine (e.g. in the console):
>
> attrs = { 'letters_attributes' => [{ 'test' => '1' }] }
> Word.new attrs
>
> But this give an error:
>
> attrs = { 'letters_attributes' => { 'test' => '1' } }
> Word.new attrs
>
> and the output looks something like:
>
> TypeError: no implicit conversion of Symbol into Integer
> from /../active_record/nested_attributes.rb:452:in `[]'
> from /../active_record/nested_attributes.rb:452:in `block in assign_nested_attributes_for_collection_association'
> from /../active_record/nested_attributes.rb:452:in `map'
> from /../active_record/nested_attributes.rb:452:in `assign_nested_attributes_for_collection_association'
> from /../active_record/nested_attributes.rb:339:in `letters_attributes='
> from /../active_record/attribute_assignment.rb:42:in `public_send'
> from /../active_record/attribute_assignment.rb:42:in `_assign_attribute'
> from /../active_record/attribute_assignment.rb:53:in `block in assign_nested_parameter_attributes'
> from /../active_record/attribute_assignment.rb:53:in `each'
> from /../active_record/attribute_assignment.rb:53:in `assign_nested_parameter_attributes'
> from /../active_record/attribute_assignment.rb:33:in `assign_attributes'
> from /../active_record/core.rb:192:in `initialize'
> from /../active_record/inheritance.rb:27:in `new'
> from /../active_record/inheritance.rb:27:in `new'
>
>
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