introduce Resque::Plugin to replace the super dance

Author: rcarver

lib/resque.rb

@@ -17,6 +17,7 @@
 require 'resque/stat'
 require 'resque/job'
 require 'resque/worker'
+require 'resque/plugin'
 
 module Resque
   include Helpers

lib/resque/job.rb

@@ -108,13 +108,14 @@ def perform
       job_args = args || []
       job_was_performed = false
 
+      plugins = payload_class.instance_variable_get(:@plugins) || []
+      plugins << payload_class
+
       begin
         # Execute before_perform hook. Abort the job gracefully if
         # Resque::DontPerform is raised.
         begin
-          if payload_class.respond_to?(:before_perform)
-            payload_class.before_perform(*job_args)
-          end
+          plugins.each { |p| p.before_perform(*job_args) if p.respond_to?(:before_perform) }
         rescue DontPerform
           return false
         end

lib/resque/plugin.rb

@@ -0,0 +1,15 @@
+module Resque
+  module Plugin
+
+    # `extend_object` is like `extended` except that we now override
+    # everything that happens when this module is extended.
+    def extend_object(obj)
+      var = :@plugins
+      obj.instance_variable_set(var, []) unless obj.instance_variable_defined?(var)
+
+      k = Class.new
+      k.send(:include, self)
+      obj.instance_variable_get(var) << k.new
+    end
+  end
+end

test/job_hooks_test.rb

@@ -310,15 +310,15 @@ def self.on_failure(exception, history)
   include PerformJob
 
   module BeforeOne
+    extend Resque::Plugin
     def before_perform(history)
-      super rescue NoMethodError
       history << :before_one
     end
   end
 
   module BeforeTwo
+    extend Resque::Plugin
     def before_perform(history)
-      super rescue NoMethodError
       history << :before_two
     end
   end