Version 6.0.0 breaks qtconsole

[frmdstryr]

ipykernel's InProcessKernelClient used by qtconsole does not use a control_channel. (see https://github.com/ipython/ipykernel/blob/master/ipykernel/inprocess/client.py#L45)

Version 6.0.0 assumes every client uses this channel and attempts to create a channel using the abstract ControlABC class which throws the error in #270 (hence the new comments).

See inkcut/inkcut#231 (comment) for a Traceback

[MSeal]

Thanks for raising, I see the change involved. I'll look at making a fix soon.

[luiztauffer]

Found the same problem when using qtconsole with jupyter-client-6.0.0.
No error with jupyter-client-5.3.4

[davidbrochart]

The control channel was introduced in KernelClient here: 5ad166c
I'm not sure it is now mandatory for clients to use this channel, or if we should fall back to the shell channel if not.

[3fon3fonov]

I can confirm this bug. Any solutions?

3fon3fonov/exostriker#55

Thanks!

[davidbrochart]

ipython/ipykernel#489 should fix it.

[frmdstryr]

Thanks!

[luiztauffer]

Is #523 expected to be included in any release soon?
The latest release 6.1.0 doesn't seem to have included the solution

[MSeal]

Read the link above, it's waiting on an ipykernel release not a jupyter_client release.

[davidbrochart]

FYI, ipykernel v5.2.0 has been released: https://github.com/ipython/ipykernel/releases/tag/5.2.0