bpo-29212: Fix the ugly repr() ThreadPoolExecutor thread name. (#2315)

bpo-29212: Fix the ugly ThreadPoolExecutor thread name.

Fixes the newly introduced ugly default thread name for concurrent.futures
thread.ThreadPoolExecutor threads.  They'll now resemble the old <=3.5
threading default Thread-x names by being named ThreadPoolExecutor-y_n.

1 files changed, 7 insertions, 1 deletions

diff --git a/Lib/concurrent/futures/thread.py b/Lib/concurrent/futures/thread.py
index 03d276b..1f0a1d4 100644
--- a/Lib/concurrent/futures/thread.py
+++ b/Lib/concurrent/futures/thread.py
@@ -7,6 +7,7 @@ __author__ = 'Brian Quinlan (brian@sweetapp.com)'
 
 import atexit
 from concurrent.futures import _base
+import itertools
 import queue
 import threading
 import weakref
@@ -81,6 +82,10 @@ def _worker(executor_reference, work_queue):
         _base.LOGGER.critical('Exception in worker', exc_info=True)
 
 class ThreadPoolExecutor(_base.Executor):
+
+    # Used to assign unique thread names when thread_name_prefix is not supplied.
+    _counter = itertools.count().__next__
+
     def __init__(self, max_workers=None, thread_name_prefix=''):
         """Initializes a new ThreadPoolExecutor instance.
 
@@ -101,7 +106,8 @@ class ThreadPoolExecutor(_base.Executor):
         self._threads = set()
         self._shutdown = False
         self._shutdown_lock = threading.Lock()
-        self._thread_name_prefix = thread_name_prefix
+        self._thread_name_prefix = (thread_name_prefix or
+                                    ("ThreadPoolExecutor-%d" % self._counter()))
 
     def submit(self, fn, *args, **kwargs):
         with self._shutdown_lock: