Customize template branch when upgrading extension

[fcollonval]

Code changes

New option --branch for the jupyterlab.upgrade_extension script to specify the template branch to be checked out.

User-facing changes

New option --branch for the jupyterlab.upgrade_extension script

Backwards-incompatible changes

N/A

[jupyterlab-dev-mode]

Thanks for making a pull request to JupyterLab!

To try out this branch on binder, follow this link:

[jtpio]

Thanks! This should make the upgrade script more flexible in the long run 👍

[jtpio]

Wondering whether this should default to the master branch of the cookiecutter, which targets the latest stable version of JupyterLab?

Staying on 3.0 sounds fine, but will require manually backporting iterations on the cookiecutter repo to its 3.0 branch.

[fcollonval]

I was hesitating to switch to master too. But I think pinning the version is better to ensure consistency for the user. If it run jupyterlab.upgrade_extension script from JupyterLab 3, it should not see upgrade of JupyterLab v4 (when it will come).

To ease maintenance on the cookiecutter project, a solution may be to change the default branch to follow the one of the current major JupyterLab (and therefore drop master) - albeit this is unconventional.

[jtpio]

To ease maintenance on the cookiecutter project, a solution may be to change the default branch to follow the one of the current major JupyterLab (and therefore drop master) - albeit this is unconventional.

Yes this is what the jupyterlab_apod repo does: https://github.com/jupyterlab/jupyterlab_apod

[blink1073]

Thanks!