PooledWorker#shutdown? checks for pool master *and* for worker parent

lib/resque/pool.rb

@@ -395,6 +395,7 @@ def spawn_worker!(queues)
       worker = create_worker(queues)
       pid = fork do
         Process.setpgrp unless Resque::Pool.single_process_group
+        worker.worker_parent_pid = Process.pid
         log_worker "Starting worker #{worker}"
         call_after_prefork!
         reset_sig_handlers!
@@ -407,6 +408,7 @@ def spawn_worker!(queues)
     def create_worker(queues)
       queues = queues.to_s.split(',')
       worker = ::Resque::Worker.new(*queues)
+      worker.pool_master_pid = Process.pid
       worker.term_timeout = ENV['RESQUE_TERM_TIMEOUT'] || 4.0
       worker.term_child = ENV['TERM_CHILD']
       if worker.respond_to?(:run_at_exit_hooks=)

lib/resque/pool/pooled_worker.rb

@@ -2,14 +2,20 @@
 
 class Resque::Pool
   module PooledWorker
+    attr_accessor :pool_master_pid
+    attr_accessor :worker_parent_pid
 
-    def initialize_with_pool(*args)
-      @pool_master_pid = Process.pid
-      initialize_without_pool(*args)
+    # We can't just check if we've been re-parented to PID 1 (init) because we
+    # want to support docker (which will make the pool master PID 1).
+    #
+    # We also check the worker_parent_pid, because resque-multi-jobs-fork calls
+    # Worker#shutdown? from inside the worker child process.
+    def pool_master_has_gone_away?
+      not potential_parent_pids.include?(Process.ppid)
     end
 
-    def pool_master_has_gone_away?
-      @pool_master_pid && @pool_master_pid != Process.ppid
+    def potential_parent_pids
+      [pool_master_pid, worker_parent_pid].compact
     end
 
     def shutdown_with_pool?
@@ -18,8 +24,6 @@ def shutdown_with_pool?
 
     def self.included(base)
       base.instance_eval do
-        alias_method :initialize_without_pool, :initialize
-        alias_method :initialize, :initialize_with_pool
         alias_method :shutdown_without_pool?, :shutdown?
         alias_method :shutdown?, :shutdown_with_pool?
       end