Assert validations API inside validatable module.

lib/devise/models/recoverable.rb

@@ -6,9 +6,11 @@ module Devise
     #
     #   # resets the user password and save the record, true if valid passwords are given, otherwise false
     #   User.find(1).reset_password!('password123', 'password123')
+    #
     #   # only resets the user password, without saving the record
     #   user = User.find(1)
     #   user.reset_password('password123', 'password123')
+    #
     #   # creates a new token and send it with instructions about how to reset the password
     #   User.find(1).send_reset_password_instructions
     module Recoverable

lib/devise/models/validatable.rb

@@ -10,7 +10,13 @@ module Devise
       # Email regex used to validate email formats. Retrieved from authlogic.
       EMAIL_REGEX = /\A[\w\.%\+\-]+@(?:[A-Z0-9\-]+\.)+(?:[A-Z]{2,4}|museum|travel)\z/i
 
+      # All validations used by this module.
+      VALIDATIONS = [ :validates_presence_of, :validates_uniqueness_of, :validates_format_of,
+                      :validates_confirmation_of, :validates_length_of ].freeze
+
       def self.included(base)
+        assert_validations_api!(base)
+
         base.class_eval do
           attribute = authentication_keys.first
 
@@ -27,6 +33,15 @@ module Devise
         end
       end
 
+      def self.assert_validations_api!(base) #:nodoc:
+        unavailable_validations = VALIDATIONS.select { |v| !base.respond_to?(v) }
+
+        unless unavailable_validations.empty?
+          raise "Could not use :validatable module since #{base} does not respond " <<
+                "to the following methods: #{unavailable_validations.to_sentence}."
+        end
+      end
+
       protected
 
         # Checks whether a password is needed or not. For validations only.

lib/devise/orm/data_mapper.rb

@@ -5,11 +5,6 @@ module Devise
         klass.send :extend, self
         yield
 
-        # DataMapper validations have a completely different API
-        if modules.include?(:validatable) && !klass.respond_to?(:validates_presence_of)
-          raise ":validatable is not supported in DataMapper, please craft your validations by hand"
-        end
-
         modules.each do |mod|
           klass.send(mod) if klass.respond_to?(mod)
         end

test/models/validatable_test.rb

@@ -96,4 +96,10 @@ class ValidatableTest < ActiveSupport::TestCase
     assert user.errors[:password]
     assert_not user.errors[:password].to_a.include?('is too short (minimum is 6 characters)')
   end
+
+  test 'shuold not be included in objects with invalid API' do
+    assert_raise RuntimeError do
+      Class.new.send :include, Devise::Models::Validatable
+    end
+  end
 end