"jupyter lab build" fails with Invalid regular expression

Dear all,

I’m running a fresh new jupyterhub 1.4.1 installtion follwoing the offcial docs.

$ jupyterhub --version
1.4.1

$ jupyter --version
jupyter core     : 4.7.1
jupyter-notebook : 6.4.0
qtconsole        : not installed
ipython          : 7.24.1
ipykernel        : 5.5.5
jupyter client   : 6.1.12
jupyter lab      : 3.0.16
nbconvert        : 6.0.7
ipywidgets       : 7.6.3
nbformat         : 5.1.3
traitlets        : 5.0.5

The hub is up and running and now I’d like to add Jupyterlab extension.
the package is installed (among others):

$ pip list|grep -i lab
jupyterlab                        3.0.16
jupyterlab-git                    0.30.1
jupyterlab-pygments               0.1.2
jupyterlab-server                 2.6.0
jupyterlab-widgets                1.0.0

$ jupyter labextension list
JupyterLab v3.0.16

Build recommended, please run `jupyter lab build`:
    No built application

but when I build it always fails with the next error:

[LabBuildApp] Node v12.19.0
[LabBuildApp] Yarn configuration loaded.
[LabBuildApp] Building jupyterlab assets (production, minimized)
[LabBuildApp] > node /apps/prod/easybuild/sl7.x86_64.foss-2021a/software/jupyterhub/1.4.1-foss-2021a-Python-3.9.5/lib/python3.9/site-packages/jupyterlab/staging/yarn.js install --non-interactive
[LabBuildApp] yarn install v1.21.1
[1/5] Validating package.json...
[2/5] Resolving packages...
success Already up-to-date.
Done in 0.46s.
[...]
[LabBuildApp] > node /apps/prod/easybuild/sl7.x86_64.foss-2021a/software/jupyterhub/1.4.1-foss-2021a-Python-3.9.5/lib/python3.9/site-packages/jupyterlab/staging/yarn.js run build:prod:minimize
[LabBuildApp] yarn run v1.21.1
$ webpack --config webpack.prod.minimize.config.js
[webpack-cli] SyntaxError: Invalid regular expression: /(\p{Uppercase_Letter}+|\p{Lowercase_Letter}|\d)(\p{Uppercase_Letter}+)/: Invalid property name
    at pathToArgumentName (/apps/prod/easybuild/sl7.x86_64.foss-2021a/software/Python/3.9.5-GCCcore-10.3.0-bare/share/jupyter/lab/staging/node_modules/webpack/lib/cli.js:66:4)
    at addFlag (/apps/prod/easybuild/sl7.x86_64.foss-2021a/software/Python/3.9.5-GCCcore-10.3.0-bare/share/jupyter/lab/staging/node_modules/webpack/lib/cli.js:170:16)
    at traverse (/apps/prod/easybuild/sl7.x86_64.foss-2021a/software/Python/3.9.5-GCCcore-10.3.0-bare/share/jupyter/lab/staging/node_modules/webpack/lib/cli.js:243:21)
    at traverse (/apps/prod/easybuild/sl7.x86_64.foss-2021a/software/Python/3.9.5-GCCcore-10.3.0-bare/share/jupyter/lab/staging/node_modules/webpack/lib/cli.js:299:23)
    at traverse (/apps/prod/easybuild/sl7.x86_64.foss-2021a/software/Python/3.9.5-GCCcore-10.3.0-bare/share/jupyter/lab/staging/node_modules/webpack/lib/cli.js:248:24)
    at Object.getArguments (/apps/prod/easybuild/sl7.x86_64.foss-2021a/software/Python/3.9.5-GCCcore-10.3.0-bare/share/jupyter/lab/staging/node_modules/webpack/lib/cli.js:308:2)
    at WebpackCLI.getBuiltInOptions (/apps/prod/easybuild/sl7.x86_64.foss-2021a/software/Python/3.9.5-GCCcore-10.3.0-bare/share/jupyter/lab/staging/node_modules/webpack-cli/lib/webpack-cli.js:591:47)
    at loadCommandByName (/apps/prod/easybuild/sl7.x86_64.foss-2021a/software/Python/3.9.5-GCCcore-10.3.0-bare/share/jupyter/lab/staging/node_modules/webpack-cli/lib/webpack-cli.js:732:38)
    at Command.<anonymous> (/apps/prod/easybuild/sl7.x86_64.foss-2021a/software/Python/3.9.5-GCCcore-10.3.0-bare/share/jupyter/lab/staging/node_modules/webpack-cli/lib/webpack-cli.js:1260:23)
    at Command.listener [as _actionHandler] (/apps/prod/easybuild/sl7.x86_64.foss-2021a/software/Python/3.9.5-GCCcore-10.3.0-bare/share/jupyter/lab/staging/node_modules/webpack-cli/node_modules/commander/index.js:922:31)
error Command failed with exit code 2.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[LabBuildApp] JupyterLab failed to build

I do not undertand the error at all. Anyone could give me hand, please?

TIA,

This looks like an issue with JupyterLab and not JupyterHub, so I’ve changed the category on your topic.