Add a deprecation cycle for `NullColumn` from `column_for_attribute`

This is public API, and `simple_form` depends on the `nil` return value.
We need to go through a deprecation cycle to return a null object. If
people want hash access, they can access the hash.

1 files changed, 2 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/associations/preloader/association.rb b/activerecord/lib/active_record/associations/preloader/association.rb
index 33c8619359..441768f302 100644
--- a/activerecord/lib/active_record/associations/preloader/association.rb
+++ b/activerecord/lib/active_record/associations/preloader/association.rb
@@ -104,11 +104,11 @@ module ActiveRecord
         end
 
         def association_key_type
-          @klass.column_for_attribute(association_key_name).type
+          @klass.type_for_attribute(association_key_name.to_s).type
         end
 
         def owner_key_type
-          @model.column_for_attribute(owner_key_name).type
+          @model.type_for_attribute(owner_key_name.to_s).type
         end
 
         def load_slices(slices)