Merge pull request #4222 from amatsuda/ar_predicate_builder_refactor

refactor AR::PredicateBuilder.build_from_hash

activerecord/lib/active_record/relation/predicate_builder.rb

@@ -15,8 +15,14 @@ module ActiveRecord
             table = Arel::Table.new(table_name, engine)
           end
 
-          attribute = table[column.to_sym]
+          build(table[column.to_sym], value)
+        end
+      end
+      predicates.flatten
+    end
 
+    private
+      def self.build(attribute, value)
         case value
         when ActiveRecord::Relation
           value = value.select(value.klass.arel_table[value.klass.primary_key]) if value.select_values.empty?
@@ -54,8 +60,4 @@ module ActiveRecord
         end
       end
   end
-
-      predicates.flatten
-    end
-  end
 end