Configurables needs to be configurable (#1037)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Steven Silvester <[email protected]>

ipykernel/ipkernel.py

@@ -12,10 +12,20 @@
 import comm
 from IPython.core import release
 from IPython.utils.tokenutil import line_at_cursor, token_at_cursor
-from traitlets import Any, Bool, Instance, List, Type, observe, observe_compat
+from traitlets import (
+    Any,
+    Bool,
+    HasTraits,
+    Instance,
+    List,
+    Type,
+    observe,
+    observe_compat,
+)
 from zmq.eventloop.zmqstream import ZMQStream
 
 from .comm.comm import BaseComm
+from .comm.manager import CommManager
 from .compiler import XCachingCompiler
 from .debugger import Debugger, _is_debugpy_available
 from .eventloops import _use_appnope
@@ -40,12 +50,18 @@
 _EXPERIMENTAL_KEY_NAME = "_jupyter_types_experimental"
 
 
-def create_comm(*args, **kwargs):
+def _create_comm(*args, **kwargs):
     """Create a new Comm."""
     return BaseComm(*args, **kwargs)
 
 
-comm.create_comm = create_comm
+def _get_comm_manager(*args, **kwargs):
+    """Create a new CommManager."""
+    return CommManager(*args, **kwargs)
+
+
+comm.create_comm = _create_comm
+comm.get_comm_manager = _get_comm_manager
 
 
 class IPythonKernel(KernelBase):
@@ -112,6 +128,7 @@ def __init__(self, **kwargs):
 
         self.comm_manager = comm.get_comm_manager()
 
+        assert isinstance(self.comm_manager, HasTraits)
         self.shell.configurables.append(self.comm_manager)
         comm_msg_types = ["comm_open", "comm_msg", "comm_close"]
         for msg_type in comm_msg_types:

ipykernel/tests/test_ipkernel_direct.py

@@ -7,7 +7,7 @@
 import zmq
 from IPython.core.history import DummyDB
 
-from ipykernel.ipkernel import BaseComm, IPythonKernel, create_comm
+from ipykernel.ipkernel import BaseComm, IPythonKernel, _create_comm
 
 from .conftest import MockIPyKernel
 
@@ -187,7 +187,7 @@ async def fake_poll_control_queue():
 
 
 def test_create_comm():
-    assert isinstance(create_comm(), BaseComm)
+    assert isinstance(_create_comm(), BaseComm)
 
 
 def test_finish_metadata(ipkernel: IPythonKernel):