validates_numericality_of works differently in 8.1.1 because of type cast

[artur79]

I'm upgrading Rails app from mongoid 7.5 to 8.1.1. I had validations like:

field :number_per_year, type: Float, default: 0

validates_numericality_of :number_per_year, allow_blank: true

When using 7.5 and I pass e.g. string 'foo' validation does not pass as expected. But in mongoid 8.1.1 as I'v found when passing string and it's not a number it's casted to number, if cast can not be done it's silently converted to nil. So now my validation passes when it should not. I'v refactored it that way:

validates_numericality_of :number_per_year, if: -> { number_per_year_before_type_cast.present? }

It works as expected now but I want to make sure are there any drawbacks/dangers in that approach?