Rails 5.2 specifying default value for class_attribute

It is very common to set a default value for a class_attribute.

Before Rails 5.2, to specify a default value for a class_attribute, we needed to write like this.

class ActivityLogger
class_attribute :logger
class_attribute :settings

self.logger = Logger.new(STDOUT)
self.settings = {}
end

As we can see above, it requires additional keystrokes to set a default value for each class_attribute.

Rails 5.2 has added support for specifying a default value for a class_attribute using default option.

class ActivityLogger
class_attribute :logger, default: Logger.new(STDOUT)
class_attribute :settings, default: {}
end

This enhancement was introduced in this pull request.