clear-cause.rb

class UnserializableError < StandardError
  def initialize(...)
    super
    @oops = -> () { }
  end
end

NormalError = Class.new(StandardError)

error = begin
  begin
    raise UnserializableError, "Won't serialize"
  rescue UnserializableError
    raise NormalError, "Normal"
  end
rescue NormalError => e
  e
end

p error
begin
  Marshal.dump(error)
rescue TypeError => e
  puts "#{e.class}: #{e.message}"
end

def clear_cause(error, new_cause)
  begin
    raise error, cause: new_cause
  rescue error.class => new_error
    return new_error
  end
end

new_error = clear_cause(error, nil)
p new_error.cause

new_error = clear_cause(error, StandardError.new)
p new_error.cause