Make ActiveRecord::Relation#pluck work with serialized attributes

2 files changed, 12 insertions, 5 deletions

diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
index 0f57e9831d..0d60810cd2 100644
--- a/activerecord/lib/active_record/relation/calculations.rb
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -168,7 +168,7 @@ module ActiveRecord
 
     # This method is designed to perform select by a single column as direct SQL query
     # Returns <tt>Array</tt> with values of the specified column name
-    # The values has same data type as column. 
+    # The values has same data type as column.
     #
     # Examples:
     #
@@ -177,9 +177,9 @@ module ActiveRecord
     #   Person.where(:confirmed => true).limit(5).pluck(:id)
     #
     def pluck(column_name)
-      scope = self.select(column_name)
-      self.connection.select_values(scope.to_sql).map! do |value|
-        type_cast_using_column(value, column_for(column_name))
+      column_name = column_name.to_s
+      klass.connection.select_all(select(column_name).arel).map! do |attributes|
+        klass.type_cast_attribute(attributes.keys.first, klass.initialize_attributes(attributes))
       end
     end
 
diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb
index 5abf3d1af4..66c801ca75 100644
--- a/activerecord/test/cases/calculations_test.rb
+++ b/activerecord/test/cases/calculations_test.rb
@@ -458,7 +458,6 @@ class CalculationsTest < ActiveRecord::TestCase
     assert_equal [ topic.approved ], relation.pluck(:approved)
     assert_equal [ topic.last_read ], relation.pluck(:last_read)
     assert_equal [ topic.written_on ], relation.pluck(:written_on)
-
   end
 
   def test_pluck_and_uniq
@@ -471,4 +470,12 @@ class CalculationsTest < ActiveRecord::TestCase
     assert_equal [contract.id], company.contracts.pluck(:id)
   end
 
+  def test_pluck_with_serialization
+    t = Topic.create!(:content => { :foo => :bar })
+    assert_equal [{:foo => :bar}], Topic.where(:id => t.id).pluck(:content)
+  end
+
+  def test_pluck_with_qualified_column_name
+    assert_equal [1,2,3,4], Topic.order(:id).pluck("topics.id")
+  end
 end