Include `Enumerable` in `ActiveRecord::Relation`

After discussing, we've decided it makes more sense to include it. We're
already forwarding every conflicting method to `to_a`, and there's no
conflation of concerns. `Enumerable` has no mutating methods, and it
just allows us to simplify the code. No existing methods will have a
change in behavior. Un-overridden Enumerable methods will simply
delegate to `each`.

[Sean Griffin & bogdan]

1 files changed, 3 insertions, 6 deletions

diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
index 29cc79db1b..7108b087f1 100644
--- a/activerecord/lib/active_record/relation/calculations.rb
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -70,12 +70,9 @@ module ActiveRecord
     # +calculate+ for examples with options.
     #
     #   Person.sum(:age) # => 4562
-    def sum(*args, &block)
-      if block_given?
-        to_a.sum(&block)
-      else
-        calculate(:sum, *args)
-      end
+    def sum(*args)
+      return super if block_given?
+      calculate(:sum, *args)
     end
 
     # This calculates aggregate values in the given column. Methods for count, sum, average,