Invoke `load_schema` in `_default_attributes`

Currently `_default_attributes` doesn't work unless `load_schema` is
called before.

The `MissingAttributeError` is caused by `reload_schema_from_cache` is
invoked by `serialize`.

I added `load_schema` in `_default_attributes` to `_default_attributes`
works without any dependency like `attribute_types` etc.

Closes #31905.

1 files changed, 1 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/model_schema.rb b/activerecord/lib/active_record/model_schema.rb
index 60823815fa..b04dc04899 100644
--- a/activerecord/lib/active_record/model_schema.rb
+++ b/activerecord/lib/active_record/model_schema.rb
@@ -379,6 +379,7 @@ module ActiveRecord
       end
 
       def _default_attributes # :nodoc:
+        load_schema
         @default_attributes ||= ActiveModel::AttributeSet.new({})
       end