Extension not loading in jupyterlab 3

In Jupyterlab 3.0.4 with Jupytext 1.9.1 on Ubuntu 20.04.1 LTS the filemanager does not appear to be loading. Specifically the log line that says the jupytext file manager loads in not showing up. I can use the console commands to pair a notebook but no additional files are saved. The GUI also does not show previously paired files as notebooks either.

I can use the most recent version of jupytext with jupyter notebook just fine. I can also downgrade to lab 2.2 and the old plugin and it works fine as well.

I have tried all variations of enabling and configuration files listed in the install documentation and nothing has worked. I am fairly sure there is a bug here but there’s no error message so it is a bit hard to say.

Let me know if there’s any more information I can provide.

Here’s a little bit of additional debug info:

g@g-ThinkPad-P51:~$ jupyter labextension list
JupyterLab v3.0.4
/home/g/.local/share/jupyter/labextensions
        jupyterlab-jupytext v1.3.0 enabled OK (python, jupytext)
        @jupyter-widgets/jupyterlab-manager v3.0.0 enabled OK (python, jupyterlab_widgets)

Other labextensions (built into JupyterLab)
   app dir: /home/g/.local/share/jupyter/lab

Contents of .jupyter/jupyter_notebook_config.json:

{
  "NotebookApp": {
    "nbserver_extensions": {
      "jupytext": true
    }
  }
}

[gstorer]

The issue is solved for me with jupyter_core==4.9.1

[mwouts]

@sbrunk , I confirm that I am able to reproduce the issue and your resolution.

On Ubuntu 20.04, I have run

sudo apt-get install pip
pip install jupytext
pip install jupyter
export PATH=$PATH:~/.local/bin

With the above I do get the configuration files for Jupytext in ~/.local/etc/jupyter

$ tree ~/.local/etc/jupyter/
/home/marc/.local/etc/jupyter/
├── jupyter_notebook_config.d
│   ├── jupyterlab.json
│   └── jupytext.json
├── jupyter_server_config.d
│   ├── jupyterlab.json
│   ├── jupytext.json
│   └── nbclassic.json
└── nbconfig
    └── notebook.d
        └── jupytext.json

4 directories, 6 files

but as you said, they are not effective because that path is not listed in jupyter --paths:

$ jupyter --paths
config:
    /home/marc/.jupyter
    /usr/etc/jupyter
    /usr/local/etc/jupyter
    /etc/jupyter
data:
    /home/marc/.local/share/jupyter
    /usr/local/share/jupyter
    /usr/share/jupyter
runtime:
    /home/marc/.local/share/jupyter/runtime

The workaround cp -r $HOME/.local/etc/jupyter/* $HOME/.jupyter/ does work.

Another possibility seems to be

export JUPYTER_CONFIG_PATH="${HOME}/.local/etc/jupyter"

I think I’ll open an issue on the Jupyter project to see what they recommend (I’ll also ask if ${HOME}/.local/etc/jupyter is a standard config location, or not)