error_messages in rails view

[Hola]

In Rails, you add error messages to the view like so:

<% remote_form_for(mymodel) do |f| %>
<%= f.error_messages %>

However, if mymodel is a Datamapper rather than an ActiveRecord model,
it produces an error:

undefined method `count' for {}:Hash

At the moment I am addressing this unfortunately by removing the call
to error_messages in the view.

Is there a better workaround?


This is the stack trace, in case it helps (I just updated to the
latest 0.10 release candidate for all dm gems).

----------------------------------------------------------------------------------------------------

C:/Ruby18/lib/ruby/gems/1.8/gems/dm-validations-0.10.0/lib/dm-
validations/validation_errors.rb:106:in `send'
C:/Ruby18/lib/ruby/gems/1.8/gems/dm-validations-0.10.0/lib/dm-
validations/validation_errors.rb:106:in `method_missing'
C:/Ruby18/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_view/
helpers/active_record_helper.rb:179:in `error_messages_for'
C:/Ruby18/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_view/
renderable.rb:77:in `inject'
C:/Ruby18/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_view/
helpers/active_record_helper.rb:179:in `each'
C:/Ruby18/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_view/
helpers/active_record_helper.rb:179:in `inject'
C:/Ruby18/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_view/
helpers/active_record_helper.rb:179:in `error_messages_for'
C:/Ruby18/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_view/
helpers/form_helper.rb:984:in `error_messages'

[Yehuda Katz]

Is #errors in 0.10 a simple Hash? It would need to duck-type like an AR errors object to work.

-- Yehuda

--
Yehuda Katz
Developer | Engine Yard
(ph) 718.877.1325

[Hola]

I believe that for #errors to pass muster in active_record_helper,
there needs to be three methods in
Datamapper::Validate::ValidationErrors: 'on', 'full_messages' and
'count'. Of these three methods, the only one that is missing is
'count'.

http://github.com/datamapper/dm-more/blob/459fd82a8923d7bf9c3d6ce64ab5f4bba7b867dc/dm-validations/lib/dm-validations/validation_errors.rb

In AR 'count' is an alias for 'size', which is a simple one-liner:

http://api.rubyonrails.org/classes/ActiveRecord/Errors.html#M002504
# File vendor/rails/activerecord/lib/active_record/validations.rb,
line 225
225: def size
226: @errors.values.inject(0) { |error_count, attribute|
error_count + attribute.size }
227: end

I'm not sure if there was a particular reason why 'count' was omitted
from the DM implementation - Is it safe for me to add my own 'count'
method along the lines of the 'size' method in AR or would this break
something in DM?

[Ted Han]

It shouldn't break anything in DM.

[Hola]

Any idea why it doesn't mirror the AR interface? Is it likely to in
the future?

On Jun 20, 5:38 pm, Ted Han <nothe...@gmail.com> wrote:
> It shouldn't break anything in DM.
>

> On Sat, Jun 20, 2009 at 5:34 PM, Hola <holacost...@gmail.com> wrote:
>
> > I believe that for #errors to pass muster in active_record_helper,
> > there needs to be three methods in
> > Datamapper::Validate::ValidationErrors: 'on', 'full_messages' and
> > 'count'. Of these three methods, the only one that is missing is
> > 'count'.
>

> >http://github.com/datamapper/dm-more/blob/459fd82a8923d7bf9c3d6ce64ab...

[Yehuda Katz]

Just FYI, in Rails3 #on was replaced with #[]. The final 0.10 should probably support both.

-- Yehuda

[Lawrence Pit]

#on still exists in Rails 3, it is aliased with #[]

There's also effort underway to have the #on method return an Error object instead of a String (where Error might inherit from String). In views you can then query each Error object for it's attribute symbol or for it's (lazily) translated error string.

http://github.com/mateomurphy/rails/blob/73ac06a165e0e255bab03f693a6158c8dc67af17/activerecord/lib/active_record/validations.rb



Lawrence

[Yehuda Katz]

Lawrence,

#on exists, but is deprecated in Rails 3.

-- Yehuda

[kristian]

this is patched if you use the rails_datamapper gem:

http://github.com/datamapper/dm-more/blob/459fd82a8923d7bf9c3d6ce64ab5f4bba7b867dc/rails_datamapper/lib/rails_datamapper/validations.rb

regards Kristian

[Hola]

Correct. Thanks, Kristian.

On Jun 21, 5:46 am, kristian <meier.krist...@gmail.com> wrote:
> this is patched if you use the rails_datamapper gem:
>

> http://github.com/datamapper/dm-more/blob/459fd82a8923d7bf9c3d6ce64ab...