How to check if object can be destroyed if it has dependent restrict associations

can_destroy.rb

class ActiveRecord::Base
  def can_destroy?
    self.class.reflect_on_all_associations.all? do |assoc|
      assoc.options[:dependent] != :restrict || (assoc.macro == :has_one && self.send(assoc.name).nil?) || (assoc.macro == :has_many && self.send(assoc.name).empty?)
    end
  end
end

nil? || empty? == blank?

assoc.options[:dependent] != :restrict || self.send(assoc.name).blank?

:restrict is deprecated. use instead:

  def can_destroy?
    self.class.reflect_on_all_associations.all? do |assoc|
      ( ([:restrict_with_error, :restrict_with_exception].exclude? assoc.options[:dependent]) ||
          (assoc.macro == :has_one && self.send(assoc.name).nil?) ||
          (assoc.macro == :has_many && self.send(assoc.name).empty?) )
    end
  end

@barakarg Thanks for your edit! It works well. 👍

@barakarg 👍

Still work in rails 4 👍

And in Rails 5 👍

I think this looks a bit cleaner..

class ActiveRecord::Base

  def can_destroy?
    self.class.reflect_on_all_associations.all? do |assoc|
      [
        %w(restrict_with_error restrict_with_exception).exclude?(assoc.options[:dependent].to_s),
        (assoc.macro == :has_one  && self.send(assoc.name).nil?),
        (assoc.macro == :has_many && self.send(assoc.name).empty?)
      ].include?(true)
    end
  end

end

And Rails 6 👍

My prefered nuance:

class ActiveRecord::Base
  def destroyable?
    self.class.reflect_on_all_associations.all? do |assoc|
      [
        %i[restrict_with_error restrict_with_exception].exclude?(assoc.options[:dependent]),
        (assoc.macro == :has_one && send(assoc.name).nil?),
        (assoc.macro == :has_many && send(assoc.name).empty?)
      ].any?
    end
  end
end

Rails 7 🎉 👍

Thanks everyone!