Show model error messages in standard way

[patmbolger]

As a developer I want to present model errors in the same way for every form.

[patmbolger]

Currently we have two different ways of presenting model error messages:

1) through code in the application layout view file, and,

2) via the partial views/shared/_error_messages.html.haml.

We should convert all instances of mechanism one to the second mechanism.

[joaopapereira]

In order to make this task easier to implement and to be able to measure the effort, please point out the changes used to move all to 2)

[patmbolger]

To do this, follow these steps for each model to be converted:

1) In the model controller, remove all statements that assign model errors to the var "@model_errors".

2) In the view(s) used for the new and edit actions, add statements at the beginning of the form that invoke the 'shared/error_messages' and assign the object: argument to your model instance. Here is an example from job_seekers/_form.html.haml:

= form_for @jobseeker, html: {class: 'form-horizontal'} do |js|
    .col-sm-offset-2.col-sm-6
        = render 'shared/error_messages', object: @jobseeker
        %br
    .clearfix

3) When all models/controllers have been converted, removed these lines from layouts/application.html.haml:

      -# The following 'if' statement will display model validation errors in the view.
      -# To use this, set the variable @model_errors equal to the errors collection of
      -# your model.  For instance, if your model is Agency and your model instance has
      -# validation errors (perhaps by calling the 'valid?' method) then this line in the
      -# controller would work:
      -#     @model_errors = @agency.errors
      - if @model_errors && @model_errors.any?
        %div{class: 'errors_explanation'}
          %h4= pluralize(@model_errors.count, 'error') + |
               " prevented this record from being saved:" |
          %ul
            - @model_errors.full_messages.each do |msg|
              %li= msg

Note:

• you can position the error messages in a way that makes sense for your specific form. Retaining the positioning starting at column 2 is a good default, however.
• do not move the positioning into the partial itself, as that partial is also used to display model errors in javascript forms.