Using validates_presence_of on a boolean field? Should use validates_inclusion_of!

rsvp.theoandpat.com had boolean flag to marked whether or not a visitor was going to be able to make it to our wedding. Unfortunately, if you selected you were not able to make it and submit the form, the application would return saying it could not process your submission because you have to say that you are going to make it. I argued, this is an RSVP form so you have to accept if you are RSVPing. That’s the point of the RSVP! Only people RSVP would bother submitting the form!  Pat wasn’t too happy about that and ask/told me to fix it. 

Digging into it, it turns out the way  for validates_presence_of relies on Object#blank which of course when sent

false.blank? # returns true

Reading up on the documentation, it is suggested to use validates_inclusion_of when dealing with booleans.

The one line change solved the problem:

validates_inclusion_of :accepted, :in => [true, false]
Posted in geekery, ruby, tutorials at January 12th, 2009. Trackback URI: trackback
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  • http://twitter.com/awws Daryl Manning

    Thanks for that ! I was wondering why that kept throwing a validation warning. definitely not the behaviour you'd expect from validate_presence_of

  • http://twitter.com/awws Daryl Manning

    Thanks for that ! I was wondering why that kept throwing a validation warning. definitely not the behaviour you'd expect from validate_presence_of

  • http://twitter.com/shooboo shooboo

    Thank you. I’ve been fighting the error for a couple of hours, now found your solution, works like a charm.