Make #unsubscribe functional when both block-based subscribers and listener objects are used

[Aerdayne]

Reproduction script:

#!/usr/bin/env ruby

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'

  gem 'dry-events', require: 'dry/events', path: '.'
end

class Monitor
  include Dry::Events::Publisher["Monitor"]
end

monitor = Monitor.new

AGGREGATOR = []

class Listener
  def on_test(event)
    p "listener: #{event}"
    AGGREGATOR << event
  end
end

listener = Listener.new
monitor.register_event(:test)

monitor.subscribe(:test) do |event|
  p "block #{event}"
  AGGREGATOR << event
end
monitor.subscribe(listener)

monitor.publish(:test, foo: "bar")

begin
  monitor.unsubscribe(listener)
rescue => e
  p e
  # => #<NoMethodError: undefined method `receiver' for #<Proc:0x000000010389a2e8 bin/console:29>>
end

Since Proc instances do not have a receiver, in case the same bus instance is subscribed to with a block and an event listener object, #unsubscribe raises an exception unless the target listener object exists and precedes the block-based subscribers in the #listeners hash.

[Aerdayne]

Hi, is there any chance this gets merged in foreseeable future?

[timriley]

Hi @Aerdayne, yes, I'll try and get this looked at in the next little while.