Old Ruby bug is recurring in my Ruby on Rails app, related to Class.create and delayed_job

The bug is many months old, here:

http://www.ruby-forum.com/topic/1094002

Two links in that which show code changes:

https://github.com/godfat/ruby/commit/f4e0e8f781b05c767ad2472a43a4ed0727a75708 https://github.com/godfat/ruby/commit/c7a6cf975d88828c2ed27d253f41c480f9b66ad6

I have Ruby 1.9.2 and rvm. I would have pasted those changes into the appropriate files, but I don't know how.

This worked a few days ago. I can't do Ruby on Rails commands like:

>> User.create :username => "a", :password => "a"

Here is the error message:

ArgumentError: wrong number of arguments(1 for 0)
from /Users/RedApple/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/yaml_tree.rb:48:in `method'
from /Users/RedApple/.rvm/rubies/ruby-1.9.2 p290/lib/ruby/1.9.1/psych/visitors/yaml_tree.rb:48:in `accept'
from /Users/RedApple/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/yaml_tree.rb:36:in `<<'
from /Users/RedApple/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych.rb:165:in `dump'
from /Users/RedApple/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/core_ext.rb:13:in `psych_to_yaml'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/delayed_job-2.0.4/lib/delayed/backend/base.rb:57:in `payload_object='
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/base.rb:2918:in `block in assign_attributes'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/base.rb:2914:in `each'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/base.rb:2914:in `assign_attributes'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/base.rb:2787:in `attributes='
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/base.rb:2477:in `initialize'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/base.rb:725:in `new'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/base.rb:725:in `create'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/delayed_job-2.0.4/lib/delayed/message_sending.rb:9:in `method_missing'
from /Users/RedApple/S/app/models/user.rb:29:in `block in <class:User>'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-2.3.14/lib/active_support/callbacks.rb:182:in `call'
... 7 levels...
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/callbacks.rb:267:in `create_with_callbacks'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/base.rb:2927:in `create_or_update'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/callbacks.rb:250:in `create_or_update_with_callbacks'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/base.rb:2577:in `save'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/validations.rb:1089:in `save_with_validation'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p2开发者_StackOverflow90/gems/activerecord-2.3.14/lib/active_record/dirty.rb:79:in `save_with_dirty'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/transactions.rb:229:in `block in with_transaction_returning_status'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/connection_adapters/abstract/database_statements.rb:136:in `transaction'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/transactions.rb:182:in `transaction'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/transactions.rb:228:in `with_transaction_returning_status'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/transactions.rb:196:in `block in save_with_transactions'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/transactions.rb:208:in `rollback_active_record_state!'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/transactions.rb:196:in `save_with_transactions'
from /Users/RedApple/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-2.3.14/lib/active_record/base.rb:727:in `create'
from (irb):1
from /Users/RedApple/.rvm/rubies/ruby-1.9.2-p290/bin/irb:16:in `<main>'>

Line 28-30 in user.rb:

after_create do |user|
  user.delay( :priority => -15 ).seed
end

I am dead in the water without this. Can anyone help?

---

Delayed Job and the Ruby 1.9.2 YAML parser (Psych) are unfortunately not compatible.

Switch back to the previous YAML parser (Syck) by adding this to your config/application.rb, just below the call to Bundler.require:

YAML::ENGINE.yamler = "syck" if RUBY_VERSION >= "1.9.2"

---

You could patch your Ruby, but it's not easy and not really possible on managed hosts. My solution was to create a monkeypatch based on the patch commit 31075.

Create an initializer file in your Rails project config/initializers/psych_extensions.rb and add this code:

# APPLIES RUBY PATCH REVISION 31075

module Psych
  module Visitors
    ###
    # YAMLTree builds a YAML ast given a ruby object.  For example:
    #
    #   builder = Psych::Visitors::YAMLTree.new
    #   builder << { :foo => 'bar' }
    #   builder.tree # => #<Psych::Nodes::Stream .. }
    #
    class YAMLTree < Psych::Visitors::Visitor

      def accept target
        # return any aliases we find
        if node = @st[target.object_id]
          node.anchor = target.object_id.to_s
          return @emitter.alias target.object_id.to_s
        end

        if target.respond_to?(:to_yaml)
          loc = target.public_method(:to_yaml).source_location.first
          if loc !~ /(syck\/rubytypes.rb|psych\/core_ext.rb)/
            unless target.respond_to?(:encode_with)
              if $VERBOSE
                warn "implementing to_yaml is deprecated, please implement \"encode_with\""
              end

              target.to_yaml(:nodump => true)
            end
          end
        end

        if target.respond_to?(:encode_with)
          dump_coder target
        else
          send(@dispatch_cache[target.class], target)
        end
      end

      private

      # FIXME: remove this method once "to_yaml_properties" is removed
      def find_ivars target
        loc = target.public_method(:to_yaml_properties).source_location.first
        unless loc.start_with?(Psych::DEPRECATED) || loc.end_with?('rubytypes.rb')
          if $VERBOSE
            warn "#{loc}: to_yaml_properties is deprecated, please implement \"encode_with(coder)\""
          end
          return target.to_yaml_properties
        end

        target.instance_variables
      end

    end
  end
end