Bug #21538: initialize_dup not called when duping class/module

• Status: Open
• Assignee: -
• Target version: -
• ruby -v: 3.4.5
• Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN

[chucke (Tiago Cardoso)]

Not sure whether this is expected behaviour or not, but just leaving it here to start the debate on whether callbacks like initialize_dup are supposed to be called when a module or class is duped (the same happens with initialize_copy and initialize_clone btw):

class A
  def initialize_dup(_)
    puts "dup instance"
    super
  end
  def self.initialize_dup(_)
    puts "dup class"
    super
  end
end

A.new.dup #=> "dup instance"
A.dup #=> nothing