How does Conditional Validation work in rails

Question

Looking through the rails code, I can't see where conditional validation gets executed... when you pass a string or an symbol to :if it supposedly does an eval for strings and a send for symbols... where does that happen?

Been trying to follow it through the code but I can't find where the if options are split into send or eval and how that all works. Just trying to learn and follow the through how rails does it.

https://github.com/rails/rails/blob/master/activemodel/lib/active_model/validator.rb https://github.com/rails/rails/blob/master/activemodel/lib/active_model/validations.rb

Thanks!

Answer 1

This method is responsible for all the symbols, strings and lambdas being executed. Seems that Rails is using activesupport callbacks to implement validations.