Merge pull request #42237 from Shopify/ar-logger-attr

Make ActiveRecord::Base.logger a class_attribute

activerecord/CHANGELOG.md

@@ -1,3 +1,10 @@
+*   `ActiveRecord::Base.logger` is now a `class_attribute`.
+
+    This means it can no longer be accessed directly through `@@logger`, and that setting `logger =`
+    on a subclass won't change the parent's logger.
+
+    *Jean Boussier*
+
 *   Add `.asc.nulls_first` for all databases. Unfortunately MySQL still doesn't like `nulls_last`.
 
     *Keenan Brock*

activerecord/lib/active_record/core.rb

@@ -17,7 +17,7 @@ module ActiveRecord
       # Accepts a logger conforming to the interface of Log4r which is then
       # passed on to any new database connections made and which can be
       # retrieved on both a class and instance level by calling +logger+.
-      mattr_accessor :logger, instance_writer: false
+      class_attribute :logger, instance_writer: false
 
       ##
       # :singleton-method: