Give preference to the second relation's order when merging

activerecord/lib/active_record/relation.rb

@@ -38,13 +38,16 @@ def merge(r)
         merged_relation = merged_relation.
           joins(arel.joins(arel)).
           group(arel.groupings).
-          order(arel.send(:order_clauses).join(', ')).
           limit(arel.taken).
           offset(arel.skipped).
           select(arel.send(:select_clauses)).
           from(arel.sources)
       end
 
+      relation_order = r.send(:order_clause)
+      merged_order = relation_order.present? ? relation_order : order_clause
+      merged_relation = merged_relation.order(merged_order)
+
       merged_wheres = @relation.wheres
 
       r.wheres.each do |w|
@@ -83,7 +86,7 @@ def to_a
             :select => @relation.send(:select_clauses).join(', '),
             :joins => @relation.joins(relation),
             :group => @relation.send(:group_clauses).join(', '),
-            :order => @relation.send(:order_clauses).join(', '),
+            :order => order_clause,
             :conditions => where_clause,
             :limit => @relation.taken,
             :offset => @relation.skipped,
@@ -156,7 +159,7 @@ def reload
     end
 
     def reset
-      @first = @last = @create_scope = @to_sql = nil
+      @first = @last = @create_scope = @to_sql = @order_clause = nil
       @records = []
       self
     end
@@ -219,6 +222,10 @@ def where_clause(join_string = " AND ")
       @relation.send(:where_clauses).join(join_string)
     end
 
+    def order_clause
+      @order_clause ||= @relation.send(:order_clauses).join(', ')
+    end
+
     def references_eager_loaded_tables?
       joined_tables = (tables_in_string(@relation.joins(relation)) + [table.name, table.table_alias]).compact.uniq
       (tables_in_string(to_sql) - joined_tables).any?

activerecord/test/cases/relations_test.rb

@@ -539,5 +539,4 @@ def test_create_bang
     assert ! hen.new_record?
     assert_equal 'hen', hen.name
   end
-
 end