bpo-43842: Fix race condition in test_logging SMTP test (GH-25436) (GH-25437) (GH-25440)

Fix a race condition in the SMTP test of test_logging. Don't close a file descriptor (socket) from a different thread while asyncore.loop() is polling the file descriptor. (cherry picked from commit 75ec103) (cherry picked from commit e1903e1)

Author: vstinner

Lib/test/test_logging.py

@@ -836,6 +836,7 @@ def __init__(self, addr, handler, poll_interval, sockmap):
  self.port = self.socket.getsockname()[1]
  self._handler = handler
  self._thread = None
+ self._quit = False
  self.poll_interval = poll_interval
 
  def process_message(self, peer, mailfrom, rcpttos, data):
@@ -867,7 +868,8 @@ def serve_forever(self, poll_interval):
  :func:`select` or :func:`poll` call by
  :func:`asyncore.loop`.
  """
- asyncore.loop(poll_interval, map=self._map)
+ while not self._quit:
+ asyncore.loop(poll_interval, map=self._map, count=1)
 
  def stop(self, timeout=None):
  """
@@ -877,9 +879,10 @@ def stop(self, timeout=None):
  :param timeout: How long to wait for the server thread
  to terminate.
  """
- self.close()
+ self._quit = True
  support.join_thread(self._thread, timeout)
  self._thread = None
+ self.close()
  asyncore.close_all(map=self._map, ignore_all=True)
 
 

Misc/NEWS.d/next/Tests/2021-04-16-14-07-40.bpo-43842.w60GAH.rst

@@ -0,0 +1,4 @@
+Fix a race condition in the SMTP test of test_logging. Don't close a file
+descriptor (socket) from a different thread while asyncore.loop() is polling
+the file descriptor.
+Patch by Victor Stinner.