Define ActiveRecord::Attribute::Null#type_cast

Using ActiveRecord::Base.attribute to declare an attribute with a default value on a model where the attribute is not backed by the database would raise a NotImplementedError when model.save is called.

The error originates from https://github.com/rails/rails/blob/59d252196b36f6afaafd231756d69ea21537cf5d/activerecord/lib/active_record/attribute.rb#L84.
This is called from https://github.com/rails/rails/blob/59d252196b36f6afaafd231756d69ea21537cf5d/activerecord/lib/active_record/attribute.rb#L46 on an ActiveRecord::Attribute::Null object.

This commit corrects the behavior by implementing ActiveRecord::Attribute::Null#type_cast.

With ActiveRecord::Attribute::Null#type_cast defined, ActiveRecord::Attribute::Null#value (https://github.com/rails/rails/blob/59d252196b36f6afaafd231756d69ea21537cf5d/activerecord/lib/active_record/attribute.rb#L173..L175) can be replaced with its super method (https://github.com/rails/rails/blob/59d252196b36f6afaafd231756d69ea21537cf5d/activerecord/lib/active_record/attribute.rb#L36..L40).

fixes #24979

1 files changed, 1 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/attribute.rb b/activerecord/lib/active_record/attribute.rb
index 3c4c8f10ec..24231dc9e1 100644
--- a/activerecord/lib/active_record/attribute.rb
+++ b/activerecord/lib/active_record/attribute.rb
@@ -170,7 +170,7 @@ module ActiveRecord
         super(name, nil, Type::Value.new)
       end
 
-      def value
+      def type_cast(*)
         nil
       end