Merge branch 'master' into instance_reader

* master: (30 commits)
  Bump tzinfo. 0.3.31 was released on November 6, 2011.
  Fix GH #4909. Dependency on TZInfo move from AR to AS.
  moving ordered hash to normal hash because ruby 1.9.3 hash defaultly ordered one
  Refactored the OrderedHash related stuff
  Replaced OrderedHash usage with Ruby 1.9 Hash
  Replaced OrderedHash with Hash for ruby 1.9 series
  removed unnecessary code
  replacing the orderhash with hash for ruby-1.9
  Clean up some wording.
  Fix typo.
  test title changed corresponding to the test
  replaced active support ordered hash to ruby hash on active resource
  PostgreSQL does not work in the same way of the other adapters
  AR::Relation#pluck: improve to work with joins
  Fix match docs
  Fix attribute_before_type_cast for serialized attributes. Fixes #4837.
  Fix failing request test
  Fixes in AMo README
  Update README to mention lint.
  Trim down Active Model API by removing valid? and errors.full_messages
  ...

1 files changed, 3 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
index 6bf3050af9..50239f7cb2 100644
--- a/activerecord/lib/active_record/relation/calculations.rb
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -177,6 +177,9 @@ module ActiveRecord
     #   Person.where(:confirmed => true).limit(5).pluck(:id)
     #
     def pluck(column_name)
+      if column_name.is_a?(Symbol) && column_names.include?(column_name.to_s)
+        column_name = "#{table_name}.#{column_name}"
+      end
       klass.connection.select_all(select(column_name).arel).map! do |attributes|
         klass.type_cast_attribute(attributes.keys.first, klass.initialize_attributes(attributes))
       end