Avoid creating temporary arrays in ActiveRecord::Result#cast_values in order to speed up pluck

1 files changed, 12 insertions, 0 deletions

diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb
index 6ceac59eec..5c9ed42173 100644
--- a/activerecord/test/cases/calculations_test.rb
+++ b/activerecord/test/cases/calculations_test.rb
@@ -642,6 +642,18 @@ class CalculationsTest < ActiveRecord::TestCase
     assert_equal [ topic.written_on ], relation.pluck(:written_on)
   end
 
+  def test_pluck_with_type_cast_does_not_corrupt_the_query_cache
+    topic = topics(:first)
+    relation = Topic.where(id: topic.id)
+    assert_queries 1 do
+      Topic.cache do
+        kind = relation.select(:written_on).load.first.read_attribute_before_type_cast(:written_on).class
+        relation.pluck(:written_on)
+        assert_kind_of kind, relation.select(:written_on).load.first.read_attribute_before_type_cast(:written_on)
+      end
+    end
+  end
+
   def test_pluck_and_distinct
     assert_equal [50, 53, 55, 60], Account.order(:credit_limit).distinct.pluck(:credit_limit)
   end