Make it so AR attributes which conflict with object-private methods (e.g. system) don't 'randomly' cause NoMethodErrors

Previously if you called this attribute before others, you'd get exceptions.  But if it was the second-or-subsequent attribute you retrieved you'd get the correct behaviour.

Signed-off-by: Michael Koziarski <michael@koziarski.com>
[#2808 state:committed]

1 files changed, 16 insertions, 0 deletions

diff --git a/activerecord/test/cases/attribute_methods_test.rb b/activerecord/test/cases/attribute_methods_test.rb
index 17ed302465..183be1e2f9 100644
--- a/activerecord/test/cases/attribute_methods_test.rb
+++ b/activerecord/test/cases/attribute_methods_test.rb
@@ -277,6 +277,22 @@ class AttributeMethodsTest < ActiveRecord::TestCase
     assert_raise(ActiveRecord::UnknownAttributeError) { @target.new.attributes = { :title => "Ants in pants" } }
   end
 
+  def test_read_attribute_overwrites_private_method_not_considered_implemented
+    # simulate a model with a db column that shares its name an inherited
+    # private method (e.g. Object#system)
+    #
+    Object.class_eval do
+      private
+      def title; "private!"; end
+    end
+    assert !@target.instance_method_already_implemented?(:title)
+    topic = @target.new
+    assert_equal nil, topic.title
+
+    Object.send(:undef_method, :title) # remove test method from object
+  end
+
+
   private
   def time_related_columns_on_topic
     Topic.columns.select{|c| [:time, :date, :datetime, :timestamp].include?(c.type)}.map(&:name)