how to define/attach rails validations in multiple generations of modules -

i've found way make work, curious better way / rails 3 way. (i'm using 2.3.5 still, hope migrate around new year's.)

the situation: i've got 2 layers of module inheritance, second layer gets mixed rails model. both modules define validation methods , i'd both of them attach validations base class, because of 2 levels of inheritance, following doesn't work:

def self.included(base)   base.validate :yadda_yadda end 

when module included module, interpreter grinds screeching halt because modules don't know activerecord::validations. including validations module begs question of "where save?" alias_method.

the following works, long remember call super whenever override validate(). don't trust myself or future maintainers remember that, i'd use validate :yadda_yadda idiom instead, if possible.

module grandpa    def validate     must_be_ok   end    def must_be_ok     errors.add_to_base("#{self} wasn't ok")   end  end  module dad    include grandpa    def validate     super     must_be_ok_too   end    def must_be_ok_too     errors.add_to_base("#{self} wasn't ok either")   end  end  class kid  < activerecord::base    include dad    validate :must_be_ok_three    def must_be_ok_three     errors.add_to_base("#{self} wasn't ok furthermore")   end  end 

suggestions? tips rails 3 approach? don't think validations api has changed much.

i solved (when ran same problem, other validation).

short answer: can call send(:included, base) on module want bring in. within higher-up included() definition, need check whether base class or module.

why ever want this? well, i've got modules extract common functionality out of models. instance, module hasallocable sets polymorphic belongs_to relationship, , getter/setter pair virtual attribute. have module needs pull in hasallocable, spare base classes having remember it.

i'd interested know whether smells funny anyone. haven't seen on web, wonder if multiple layers of model inheritance more of antipattern.

module grandpa    def self.included(base)     if base.kind_of?(class)       base.validate :must_be_ok     end   end  end  module dad    include grandpa    def self.included(base)     if base.kind_of?(class)       # can       #base.send(:include, grandpa)       # can       grandpa.send(:included, base)       # not invoke grandpa.included(kid)       #super(base)        base.validate :must_be_ok_too     end   end  end  class kid  < activerecord::base   include dad   validate :must_be_ok_three end