ArgumentError in new for an enum parameter in rails 5.1

Question

I have a model, Announcement, with an enum

Audience = ['everyone', 'signed_in_only','visitor_only', 'app_only', 'exclude_app']
enum audience: Audience

The announcements controller defines audience_params

def announcement_params
  params.require(:announcement).permit(:body, :audience, :expiry)
end

In creating an announcement, the audience_params are

<ActionController::Parameters {"body"=>"This is for everyone", "audience"=>"0", "expiry"=>"27/01/2018"} permitted: true>

My code in the action method of the announcements controller includes

@announcement = Announcement.new(announcement_params)
@announcement.audience = @announcement.audience.to_i

which worked with rails 5.0. But now the first line throws an exception

ArgumentError: '0' is not a valid audience

presumably because the audience value has not been converted to integer. Given the new method does not do validations, why is this error being thrown in rails 5.1 and how do I fix this?

Answer 1

enum is meant to allow you to use symbolic names rather than numbers. The accessors they define expect you to give a string or symbol, rather than the underlying numeric value.

You should be using

@announcement.audience = 'everyone'

not

@announcement.audience = 0

This behavior may have changed in newer Rails, but the correct thing has always been to assign the human-readable string, not the numeric value.

Answer 2

Rails 5.2 you can call .to_sym on the passed string and model creates and saves. As regards to just using the string, hmmm, there's probably a reason the automagic isn't working in my case so I'd try that first.