Add AssociationCollection#sum since the method_missing invokation has been shadowed by Enumerable#sum. Closes #5500.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4493 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 11 insertions, 0 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 23845ebaf0..ccce8c44c5 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Add AssociationCollection#sum since the method_missing invokation has been shadowed by Enumerable#sum.
+
 * Added find_or_initialize_by_X which works like find_or_create_by_X but doesn't save the newly instantiated record. [Sam Stephenson]
 
 * Row locking. Provide a locking clause with the :lock finder option or true for the default "FOR UPDATE". Use the #lock! method to obtain a row lock on a single record (reloads the record with :lock => true). [Shugo Maeda]
diff --git a/activerecord/lib/active_record/associations/association_collection.rb b/activerecord/lib/active_record/associations/association_collection.rb
index 61ad6ab7b6..ec7af7913d 100644
--- a/activerecord/lib/active_record/associations/association_collection.rb
+++ b/activerecord/lib/active_record/associations/association_collection.rb
@@ -42,6 +42,11 @@ module ActiveRecord
         reset_target!
       end
 
+      # Calculate sum using SQL, not Enumerable
+      def sum(*args, &block)
+        calculate(:sum, *args, &block)
+      end
+
       # Remove +records+ from this association.  Does not destroy +records+.
       def delete(*records)
         records = flatten_deeper(records)
diff --git a/activerecord/test/calculations_test.rb b/activerecord/test/calculations_test.rb
index 67de1b9bd5..7b89e8c62c 100644
--- a/activerecord/test/calculations_test.rb
+++ b/activerecord/test/calculations_test.rb
@@ -147,6 +147,10 @@ class CalculationsTest < Test::Unit::TestCase
     assert_equal 3, c['CLIENT']
     assert_equal 2, c['FIRM']
   end
+  
+  def test_should_not_overshadow_enumerable_sum
+    assert_equal 6, [1, 2, 3].sum(&:abs)
+  end
 
   def test_should_sum_scoped_field
     assert_equal 15, companies(:rails_core).companies.sum(:id)