Bug #13115: `YAML.dump` outputs deperecated message even with delegated object

• Status: Closed
• Assignee: tenderlovemaking (Aaron Patterson)
• Target version: -
• ruby -v: ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]
• Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN

[mtsmfm (Fumiaki Matsushima)]

YAML.dump outputs deprecated message if it calls with delegated object
but doesn't with inherited object:

require 'yaml'
require 'delegate'

$VERBOSE = true
class Delegated < DelegateClass(Object)
  def initialize
    super(Object.new)
  end
end

puts 'YAML.dump(Delegated.new)'
YAML.dump(Delegated.new)

class Inherited < Object
end
puts 'YAML.dump(Inherited.new)'
YAML.dump(Inherited.new)

# $ ruby test.rb
# YAML.dump(Delegated.new)
# implementing to_yaml is deprecated, please implement "encode_with"
# YAML.dump(Inherited.new)

Is this intentional?

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Assigned
• Assignee set to tenderlovemaking (Aaron Patterson)

Psych warns if to_yaml method is defined by other than psych itself, and delegated methods are defined in delegate.rb.
You can avoid the warning by undef to_yaml in class Delegated.

[tenderlovemaking (Aaron Patterson)]

• Status changed from Assigned to Closed

This has been fixed since Psych 3.0.0 https://github.com/ruby/psych/commit/712a65a53f3c15105cd86e8ad3ee3c779050ada4