1 files changed, 9 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
index 2336d23a1c..67b8efac66 100644
--- a/activerecord/lib/active_record/locking/optimistic.rb
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -150,7 +150,7 @@ module ActiveRecord
 
         # The version column used for optimistic locking. Defaults to +lock_version+.
         def locking_column
-          reset_locking_column unless defined?(@locking_column)
+          @locking_column = DEFAULT_LOCKING_COLUMN unless defined?(@locking_column)
           @locking_column
         end
 
@@ -184,9 +184,16 @@ module ActiveRecord
       end
     end
 
+
+    # In de/serialize we change `nil` to 0, so that we can allow passing
+    # `nil` values to `lock_version`, and not result in `ActiveRecord::StaleObjectError`
+    # during update record.
     class LockingType < DelegateClass(Type::Value) # :nodoc:
       def deserialize(value)
-        # `nil` *should* be changed to 0
+        super.to_i
+      end
+
+      def serialize(value)
         super.to_i
       end