1 files changed, 16 insertions, 4 deletions
diff --git a/activerecord/lib/active_record/associations/association_proxy.rb b/activerecord/lib/active_record/associations/association_proxy.rb
index 75218c01d2..9b96ec0cf4 100644
--- a/activerecord/lib/active_record/associations/association_proxy.rb
+++ b/activerecord/lib/active_record/associations/association_proxy.rb
@@ -256,10 +256,22 @@ module ActiveRecord
           end
         end
 
-        # Array#flatten has problems with recursive arrays. Going one level
-        # deeper solves the majority of the problems.
-        def flatten_deeper(array)
-          array.collect { |element| (element.respond_to?(:flatten) && !element.is_a?(Hash)) ? element.flatten : element }.flatten
+        if RUBY_VERSION < '1.9.2'
+          # Array#flatten has problems with recursive arrays before Ruby 1.9.2.
+          # Going one level deeper solves the majority of the problems.
+          def flatten_deeper(array)
+            array.collect { |element| (element.respond_to?(:flatten) && !element.is_a?(Hash)) ? element.flatten : element }.flatten
+          end
+        else
+          def flatten_deeper(array)
+            array.sum [] do |elem|
+              if elem.respond_to?(:each)
+                flatten_deeper(elem)
+              else
+                Array.wrap(elem)
+              end
+            end
+          end
         end
 
         # Returns the ID of the owner, quoted if needed.