celluloid_deadlock.rb

require 'celluloid/current'

class Receiver
  include Celluloid
  include Celluloid::Notifications

  def initialize(blocking = true)
    @queue = Queue.new
    subscribe('deadlock', :got_notified)
    blocking ? async.work_blocking : async.work_non_blocking
  end

  def work_non_blocking
    puts 'checking queue'
    puts @queue.pop(true)
  rescue ThreadError
    puts 'nothing in queue, retrying'
    sleep 1
    retry
  end

  def work_blocking
    puts 'checking queue'
    puts @queue.pop
  end

  def got_notified(_topic, payload)
    puts 'got notified'
    @queue << payload
  end
end

class Sender
  include Celluloid
  include Celluloid::Notifications

  def initialize
    async.work
  end

  def work
    sleep 2
    publish('deadlock', 'foo')
  end
end

Receiver.new(false)
Sender.new

sleep