Rework to instead not put PID into pipe

Author: tfzee

Lib/concurrent/futures/process.py

@@ -249,8 +249,6 @@ def _process_worker(call_queue, result_queue, initializer, initargs, max_tasks=N
     while True:
         call_item = call_queue.get(block=True)
         if call_item is None:
-            # Wake up queue management thread
-            result_queue.put(os.getpid())
             return
 
         if max_tasks is not None:
@@ -531,9 +529,6 @@ def wait_result_broken_or_wakeup(self):
         return result_item, is_broken, cause
 
     def process_result_item(self, result_item):
-        # Process the received a result_item. This can be either the PID of a
-        # worker that exited gracefully or a _ResultItem
-
         # Received a _ResultItem so mark the future as completed.
         work_item = self.pending_work_items.pop(result_item.work_id, None)
         # work_item can be None if another process terminated (see above)
@@ -678,17 +673,9 @@ def _join_executor_internals(self, broken=False):
 
         # If .join() is not called on the created processes then
         # some ctx.Queue methods may deadlock on Mac OS X.
-        result_reader = self.result_queue._reader
         for p in self.processes.values():
             if broken:
                 p.terminate()
-            else:
-                # Exiting workers put their pid on the result queue. Keep
-                # draining it, otherwise once the pipe is full a worker
-                # blocks forever writing to it and never exits.
-                while p.sentinel not in mp.connection.wait(
-                        [result_reader, p.sentinel]):
-                    result_reader.recv_bytes()
             p.join()
 
     def get_n_children_alive(self):