objid.rb

# require "objspace"
# puts ObjectSpace.dump(Object.new)
# puts ObjectSpace.dump(Object.new.tap(&:object_id))
# puts ObjectSpace.dump_all(since: 1, output: :stdout)

o = Object.new
p [o.object_id, o.object_id]
o = Marshal.load(Marshal.dump(o))
p [o.object_id, o.object_id]

ObjectSpace._id2ref(8)

o = o.dup
p [o.object_id, o.object_id]

o = o.clone
p [o.object_id, o.object_id]

o = Hash.new
p [o.object_id, o.object_id]
o = Marshal.load(Marshal.dump(o))
p [o.object_id, o.object_id]

o = Class.new
p [o.object_id, o.object_id]

class TooComplex
end
20.times do |i|
  TooComplex.new.instance_variable_set("@a#{i}", 1)
end

o = TooComplex.new
o.instance_variable_set("@b", 1)
p [o.object_id, o.object_id]
o = Marshal.load(Marshal.dump(o))
p [o.object_id, o.object_id]


o = TooComplex.new
id = o.object_id
o.instance_variable_set("@b", 1)
p [id, o.object_id]

GC.start

def fin
  ->(id) { p [:fin, id] }
end
o = Object.new
p [o.object_id, o.object_id]
ObjectSpace.define_finalizer(o, fin)

o = nil
GC.start