Adding Proc support to validation messages so that they can become a little more dynamic, allowing for customisations during the request [#3514 status:resolved].

Signed-off-by: José Valim <jose.valim@gmail.com>

2 files changed, 10 insertions, 0 deletions

diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index 0b6c75c46e..2e5bcab070 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -60,9 +60,11 @@ module ActiveModel
     # error can be added to the same +attribute+ in which case an array will be returned on a call to <tt>on(attribute)</tt>.
     # If no +messsage+ is supplied, :invalid is assumed.
     # If +message+ is a Symbol, it will be translated, using the appropriate scope (see translate_error).
+    # If +message+ is a Proc, it will be called, allowing for things like Time.now to be used within an error
     def add(attribute, message = nil, options = {})
       message ||= :invalid
       message = generate_message(attribute, message, options) if message.is_a?(Symbol)
+      message = message.call if message.is_a?(Proc)
       self[attribute] << message
     end
 
diff --git a/activemodel/test/cases/validations_test.rb b/activemodel/test/cases/validations_test.rb
index 38a2a716a7..eb100d1c35 100644
--- a/activemodel/test/cases/validations_test.rb
+++ b/activemodel/test/cases/validations_test.rb
@@ -212,4 +212,12 @@ class ValidationsTest < ActiveModel::TestCase
     all_errors = t.errors.to_a
     assert_deprecated { assert_equal all_errors, t.errors.each_full{|err| err} }
   end
+
+  def test_validation_with_message_as_proc
+    Topic.validates_presence_of(:title, :message => proc { "no blanks here".upcase })
+
+    t = Topic.new
+    assert !t.valid?
+    assert ["NO BLANKS HERE"], t.errors[:title]
+  end
 end