Restore an ability that class level `update` without giving ids

That ability was introduced at #11898 as `Relation#update` without
giving ids, so the ability on the class level is not documented and not
tested.

c83e30d which fixes #33470 has lost two undocumented abilities.

One has fixed at 5c65688, but I missed the ability on the class level.

Removing any feature should not be suddenly happened in a stable version
even if that is not documented.

I've restored the ability and added test case to avoid any regression in
the future.

Fixes #34743.

1 files changed, 3 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
index 7bf8d568df..c2b60610ce 100644
--- a/activerecord/lib/active_record/persistence.rb
+++ b/activerecord/lib/active_record/persistence.rb
@@ -96,11 +96,13 @@ module ActiveRecord
       # When running callbacks is not needed for each record update,
       # it is preferred to use {update_all}[rdoc-ref:Relation#update_all]
       # for updating all records in a single query.
-      def update(id, attributes)
+      def update(id = :all, attributes)
         if id.is_a?(Array)
           id.map { |one_id| find(one_id) }.each_with_index { |object, idx|
             object.update(attributes[idx])
           }
+        elsif id == :all
+          all.each { |record| record.update(attributes) }
         else
           if ActiveRecord::Base === id
             raise ArgumentError,