fix for repl hang when using with pyzmq => 18.0.0 (#5252)

 fix for repl hang when using  with pyzmq => 18.0.0

- Both execute(..) and get_shell_msg(..) act on the same shell socket and having a blocking call to get_shell_msg(..) no longer works with the newer pyzmq.
- temporary fix was to downgrade pyzmq to 17.1.3
- Changed get_shell_msg(..) to use a timeout instead of blocking.

related to bug  #5233

Python/Product/PythonTools/ptvsd/repl/jupyter_client.py

@@ -343,25 +343,28 @@ def __shell_threadproc(self, client):
  if self.exit_requested:
  break
 
- m = Message(client.get_shell_msg(block=True))
- msg_id = m.msg_id
- msg_type = m.msg_type
-
- print('%s: %s' % (msg_type, msg_id))
-
- exec_count = m.content['execution_count', None]
- if exec_count != last_exec_count and exec_count is not None:
- last_exec_count = exec_count
- exec_count = int(exec_count) + 1
- ps1 = 'In [%s]: ' % exec_count
- ps2 = ' ' * (len(ps1) - 5) + '...: '
- self.send_prompt('\n' + ps1, ps2, allow_multiple_statements=True)
-
- parent_id = m.parent_header['msg_id', None]
- if parent_id:
- on_reply = on_replies.pop((parent_id, msg_type), ())
- for callable in on_reply:
- callable(m)
+ try:
+ m = Message(client.get_shell_msg(timeout=0.1))
+ msg_id = m.msg_id
+ msg_type = m.msg_type
+
+ print('%s: %s' % (msg_type, msg_id))
+
+ exec_count = m.content['execution_count', None]
+ if exec_count != last_exec_count and exec_count is not None:
+ last_exec_count = exec_count
+ exec_count = int(exec_count) + 1
+ ps1 = 'In [%s]: ' % exec_count
+ ps2 = ' ' * (len(ps1) - 5) + '...: '
+ self.send_prompt('\n' + ps1, ps2, allow_multiple_statements=True)
+
+ parent_id = m.parent_header['msg_id', None]
+ if parent_id:
+ on_reply = on_replies.pop((parent_id, msg_type), ())
+ for callable in on_reply:
+ callable(m)
+ except Empty:
+ pass
 
  except zmq.error.ZMQError:
  self.exit_process()