accepts_nested_attributes_for :reject_if

rubyonrails-core
1

Currently the :reject_if option on accepts_nested_attributes_for rejects the nested attributes when #valid? is called on the parent association. I think better behavior would be to reject the nested attributes only upon saving the parent association. Consider this case:

Class Gift < ActiveRecord::Base   has_many :contributions   accepts_nested_attributes_for :contributions, :reject_if => proc { | a> a['amount'].blank? }

If Contribution has a :nickname attribute which is filled in on a @gift form, when the form makes a round trip through a failed validation, the nested contribution_attributes are rejected. The better outcome is to preserver these attributes so the form contains all the data the user entered. Ultimately, if the :reject_if condition is met, the association will be rejected when @gift.save succeeds.

Carlos, I saw you commented on the :all_blank Rails ticket. What's your opinion on this? Worth ticketing?

Gavin

2

I don't really understand the use case here. Wouldn't you solve the problem by adding a "nickname.blank?" check in addition to the amount?

Similarly if the user specifies a nickname without an amount maybe it should be left to validations and the reject_if removed.

Or am I missing something?

Regards, Andrew

3

Hello Gavin,

If I really understood your problem, what Andrew said should solve it... Just by adding 'nickname' to your :reject_if proc should validate whenever you have a nickname or amount in contribution_attributes.

The :reject_if should verify conditions you feel reasonable to discard that record from being created and validated. This way, if the contribution has no 'nickname' and 'amount', it'd be discarded.

Regards, Carlos Antonio.

4

The question is: When a form makes a round trip through validation, should it return containing the data the user originally entered? With non-nested attributes, we don’t arbitrarily discard data, why do we do this with nested attributes? In general, why are we discarding stuff in the validation process?

:nickname and :amount, :reject_if => proc {|a| a[‘amount’].blank?

Presence of :nickname is not required, but data added to it should still be preserved when my forms returns after failing validation on some other attribute. Otherwise, the user is left thinking “Hmm… I filled something in here, why is it empty?”

I can make this behave as I require, but the extra code I write is only there because AR is discarding data during validation. This feels wrong, doesn’t it?

Gavin

5

The question is: When a form makes a round trip through validation, should it return containing the data the user originally entered? With non-nested attributes, we don't arbitrarily discard data, why do we do this with nested attributes? In general, why are we discarding stuff in the validation process?

Because, like Carlos said, it's meant as a mean to completely disregard records from being created in the cases where you don't deem the data important or entered by the user.

Say you create a few new objects, on the server or client side, so the user can make new records if they want to, but the user doesn't actually enter any data, that's when you'd want to reject it.

More specific, say the form has a checkbox, this means that even though the user didn't enter any information, there will still be data sent to the server. In those cases you'd use :reject_if to disregard it at all.

You should _not_ use it if you don't actually want to reject them, but use validation to see if the data that was sent satisfies the needs. In short, it's a different concern.

Eloy