`update_column` take ruby-land input, not database-land input

In the case of serialized columns, we would expect the unserialized
value as input, not the serialized value. The original issue which made
this distinction, #14163, introduced a bug. If you passed serialized
input to the method, it would double serialize when it was sent to the
database. You would see the wrong input upon reloading, or get an error
if you had a specific type on the serialized column.

To put it another way, `update_column` is a special case of
`update_all`, which would take `['a']` and not `['a'].to_yaml`, but you
would not pass data from `params` to it.

Fixes #18037

1 files changed, 4 insertions, 2 deletions

diff --git a/activerecord/test/cases/serialized_attribute_test.rb b/activerecord/test/cases/serialized_attribute_test.rb
index 66f345d805..56a0e92e1d 100644
--- a/activerecord/test/cases/serialized_attribute_test.rb
+++ b/activerecord/test/cases/serialized_attribute_test.rb
@@ -243,8 +243,9 @@ class SerializedAttributeTest < ActiveRecord::TestCase
     t = Topic.create(content: "first")
     assert_equal("first", t.content)
 
-    t.update_column(:content, Topic.type_for_attribute('content').type_cast_for_database("second"))
-    assert_equal("second", t.content)
+    t.update_column(:content, ["second"])
+    assert_equal(["second"], t.content)
+    assert_equal(["second"], t.reload.content)
   end
 
   def test_serialized_column_should_unserialize_after_update_attribute
@@ -253,5 +254,6 @@ class SerializedAttributeTest < ActiveRecord::TestCase
 
     t.update_attribute(:content, "second")
     assert_equal("second", t.content)
+    assert_equal("second", t.reload.content)
   end
 end