Why Aren't These Errors Rendering For Nested Associations? - ruby-on-rails

Question

I have a MediaItem model that has two has_one associations. I validate that one or the other are present using:
validates_presence_of :photo, allow_nil: true
validates_presence_of :video, allow_nil: true
validate :photo_or_video_present
def photo_or_video_present
if !(photo.blank? ^ video.blank?)
errors['photo_attributes.image'] << 'Select a photo or a video'
errors['video_attributes.uid'] << 'Select a photo or a video'
end
end
Which gives me the following error object when the form is rendered:
<ActiveModel::Errors:0x007f99c8a71fc0
#base=#<MediaItem id: nil,
title: "asdadasdasd",
slug: "asdadasdasd",
gallery_id: 1,
created_at: nil,
updated_at: nil>,
#messages={:"photo_attributes.image"=>["Select a photo or a video"],
:"video_attributes.uid"=>["Select a photo or a video"],
:title=>[] }>
However these errors don't show up in the nested models. The form looks like this:
<div class="FormWrapper">
<%= simple_form_for [:admin, #gallery, #media_item], html: { class: "#{action_name.titleize}PhotoForm" } do |f| %>
<%= f.input :title %>
<div class="PhotoInputs">
<h3>Photo</h3>
<%= f.simple_fields_for :photo do |ff| %>
<%= ff.input :image, as: :file_upload, input_html: {preview: #media_item.photo.image} %>
<% end %>
</div>
<div class="VideoInputs">
<h3>Video</h3>
<%= f.simple_fields_for :video do |ff| %>
<%= ff.input :provider, as: :radio_buttons, collection: Video::PROVIDERS %>
<%= ff.input :uid %>
<% end %>
</div>
<hr>
<%= render partial: 'shared/form_submit', locals: {resource: #media_item} %>
<% end %>
</div>
Why are these inline errors failing to show up?
Note: There is no absolutely no problem with the functioning of the form. I can create and edit both model and nested model without issue.

Answer 1

These 2 validations do nothing validates_presence_of :photo, allow_nil: true validates_presence_of :video, allow_nil: true because you are validating the presence but allowing it to not be present. I would just add the error to :base and render that in the view. e.g.
validates :has_photo_or_video
def has_photo_or_video
if (photo.blank? ^ video.blank?)
errors.add(:base,"Please select a photo or video")
end
end
Then in the view
<% f.errors[:base].each do |message| %>
<span>message</span>
<% end %>
I have not seen an implementation of inline errors like you describe although you could try something like this as well:
def has_photo_or_video
if !(photo.blank? ^ video.blank?)
photo.errors.add(:image,"Please select a photo or video")
video.errors.add(:uid,"Please select a photo or video")
end
end
Although I make no representation as to whether or not this will work.
Your issue is that it is looking for your errors to be contained in a nested hash like
{photo_attributes: {image: ["Please select a photo or video"]},
video_attributes: {uid: ["Please select a photo or video"]} }
The only way I have seen this done is by validating on the associated model which is not possible in your case since it is a one or both type procedure. At least as I understand it.
If this is an either or type procedure meaning a MediaItem is either a Photo or a Video but not both then I would suggest looking into polymorphism as it would make this procedure far easier.
Or even better still scrap MediaItem all together and add the title attribute to Photo and Video and then create each one separately as this seems like the easiest route. (You could still define a method for media_items that would grab all of these)