Differentiating between `blank` and `not_a_date`

[CeeBeeUK]

Hello,

I'm trying to set up date validation on a field that requires a valid date be input.

validates :dob, date: true, presence: true renders both the blank and not_a_date messages.

I am working on a fork that would change the functionality so that passing:

• nil to validates :dob, date: true would return en.errors.messages.blank
• 'bob' to validates :dob, date: true would return en.errors.messages.not_a_date

Is this something that would be welcomed as a pull request or should I keep it separate?

[dgmstuart]

Yup - I've been bitten by that one. The solution is to use

date: { allow_blank: true }

So the date validation won't get run if date is not present.

[mlt]

I have something like

  validates :effective_to, date: { allow_blank: true, after: :effective_from }

It complains if effective_to is blank :( ["Effective to is not a date"]

[dgmstuart]

@mlt Here's a section of code involved, which suggests that your code above should work:

https://github.com/codegram/date_validator/blob/0a1f7aecac9c8afe3967dd622767505df607b7e4/lib/active_model/validations/date_validator.rb#L52-L71

A blank string can be many things: nil, empty string, string containing only whitespace, false - which is it in your scenario?

[mlt]

My bad! I was messing around with parameter coercion substitution that I want to treat blank as infinite. This fragment indeed does work! However, there is another problem. It doesn't respect DateTime::Infinity that was coming from my strong params filter. I forgot I added

      p[:effective_to] = DateTime::Infinity if p.fetch(:effective_to, '').blank?

Note, that

validates :effective_to, date: { after: :effective_from }, unless: Proc.new{ |p| p.effective_to.blank? }

worked fine with blank (actually infinite) parameter. It seems to me they should be equivalent.