ActiveModel::Errors#generate_message without i18n_scope, and more test cases for #add

[martinsvalin]

ActiveModel::Errors#generate_message requires that the model we're adding errors to implements i18n_scope. This is not obvious from the documentation, and it is also not necessary as there are translation fallbacks that don't use i18n_scope.

The first of the three commits skips the translation defaults where i18n_scope is used if the model doesn't respond to it.

I also noticed that there were no tests on ActiveModel::Errors#add when message is a Symbol, or when message is a Proc. I wrote tests for these cases, each in it's own commit to make it easier if you'd like to pull these but not the commit dealing with i18n_scope.

Please bear in mind that, if you'd like to keep the requirement for 18n_scope on the model, the test case for when message is a Symbol won't pass. If generate_message doesn't check if the model responds, the test needs a minimal implementation of Person.i18n_scope to pass. I'll be happy to fix this.

PS. This is my first contribution to Rails. Yay! \o/
I attended an Open Source Hack Night in Stockholm on October 11. Kudos to Valtech for organizing it.

[josevalim]

This if clause should actually be outside the loop. Something like:

if @base.class.respond_to?(:i18n_scope)
  defaults = @base.class.lookup_ancestors.map do |klass|
    [ :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.i18n_key}.attributes.#{attribute}.#{type}",
      :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.i18n_key}.#{type}" ]
  end
else
  defaults = []
end

[josevalim]

This looks great. I have added one comment, could you please check it out? And congratulations on your first contribution.

[martinsvalin]

Glad you liked it. You're right. Brevity is nice, but not if it means needlessly rechecking respond_to?. I've moved it outside the block.

[josevalim]

This looks great! Could you please squash those commits into one? Thanks!

[martinsvalin]

Ok, I squashed them in an interactive rebase, and then force pushed to my branch on github, but it hasn't turned up here in the pull request. I don't have a lot of experience with github pull requests, so maybe I did something I shouldn't have.

My squashed commit is available at martinsvalin@180d413

[josevalim]

Github takes some times to update pull requests, everything looks great for me now! Thanks!