Merge pull request python-trio#1298 from njsmith/workaround-1293

Work around openssl Connection(Reset|Aborted)Error on Windows

trio/tests/test_ssl.py

@@ -107,6 +107,22 @@ def ssl_echo_serve_sync(sock, *, expect_fail=False):
  pass
  return
  wrapped.sendall(data)
+ # This is an obscure workaround for an openssl bug. In server mode, in
+ # some versions, openssl sends some extra data at the end of do_handshake
+ # that it shouldn't send. Normally this is harmless, but, if the other
+ # side shuts down the connection before it reads that data, it might cause
+ # the OS to report a ECONNREST or even ECONNABORTED (which is just wrong,
+ # since ECONNABORTED is supposed to mean that connect() failed, but what
+ # can you do). In this case the other side did nothing wrong, but there's
+ # no way to recover, so we let it pass, and just cross our fingers its not
+ # hiding any (other) real bugs. For more details see:
+ #
+ # https://github.com/python-trio/trio/issues/1293
+ #
+ # Also, this happens frequently but non-deterministically, so we have to
+ # 'no cover' it to avoid coverage flapping.
+ except (ConnectionResetError, ConnectionAbortedError): # pragma: no cover
+ return
  except Exception as exc:
  if expect_fail:
  print("ssl_echo_serve_sync got error as expected:", exc)