Ruby Forum Rails-core (closed, excessive spam) > Edge fails saving parent when has_many child ?

Hi !

I have these models:

class Invoice < AR::Base
  has_many :lines, :class_name => 'InvoiceLine'
end

class InvoiceLine < AR::Base
  belongs_to :invoice
end

This fails at the console:

$ ruby script\console
Loading development environment.
>> invoice = Invoice.new
=> #<Invoice:0x3a76060 ...>
>> line = invoice.lines.build
=> #<InvoiceItem:0x3a5d610 ...>
>> invoice.save!
ActiveRecord::RecordInvalid: Validation failed: Lines is invalid
        from 
./script/../config/../config/../vendor/rails/activerecord/lib/active_record/validations.rb:736:in
`save!'
        from (irb):3
>> puts line.errors.full_messages
Invoice can't be blank

I was under the impression that saving the parent should correctly
save the children in has_many relationships.  Of course, if I save the
parent before the child, it works.  But then I lose #new_record?  Of
course, AR::Base has an attribute named @new_record_before_save, but
there are no accessors for it.

http://dev.rubyonrails.org/browser/trunk/activerecord/lib/active_record/associations.rb#L93
seems to imply that the use case above will work, while
http://dev.rubyonrails.org/browser/trunk/activerecord/lib/active_record/associations.rb#L279
says it won't work if "this object" is nil.  "this object" is
obviously not nil, but it hasn't received it's primary key yet.

Question #1:  Should saving the parent record correctly save the child 
record ?
Question #2:  Should we provide an accessor for @new_record_before_save

Thanks !

I've also come up to this oddity and I'd like to know the answer to
the questions pose--is the author of the original code present, or an
otherwise knowledgeable person who could answer?

Duane Johnson
(canadaduane)

2006/3/8, Duane Johnson <duane.johnson@gmail.com>:
> I've also come up to this oddity and I'd like to know the answer to
> the questions pose--is the author of the original code present, or an
> otherwise knowledgeable person who could answer?

Ok, I found the solution:

http://blog.teksol.info/articles/2006/03/08/do-not-validate-belongs_to-or-else

Summary:

class Child < AR::Base
  validates_presence_of :parent_id
end

NOT

class Child < AR::Base
  validates_presence_of :parent
end

Bye !

2006/3/8, Francois Beausoleil <francois.beausoleil@gmail.com>:
> class Child < AR::Base
>   validates_presence_of :parent_id
> end

http://dev.rubyonrails.org/ticket/4147