sage -n: Warn the user if user configuration shadows our kernels

[mkoeppe]

(from #33650 comment:7)

In https://doc.sagemath.org/html/en/installation/launching.html#setting-up-sagemath-as-a-jupyter-kernel-in-an-existing-jupyter-notebook-or-jupyterlab-installation we tell users to install the kernelspec of a Sage installation using jupyter kernelspec install --user.

But we forget to tell them that it will shadow the kernel invoked by sage -n globally (for every copy of Sage), unless --name is used to rename it from sagemath to something more specific.

In this ticket:

• We adjust the documentation
• We have sage -n issue a warning if the user configuration shadows the kernels

CC: @kwankyu @dimpase

Component: user interface

Author: Matthias Koeppe, Kwankyu Lee

Branch/Commit: 0add420

Reviewer: Kwankyu Lee, Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/33651

[mkoeppe]

comment:2

This is how we can read out the kernel_spec.

sage: from jupyter_client.kernelspec import get_kernel_spec
sage: spec = get_kernel_spec('sagemath')
sage: spec.argv[0]
'/Users/mkoeppe/s/sage/sage-rebasing/worktree-gcc11/local/var/lib/sage/venv-python3.10/bin/sage'

[mkoeppe]

Branch: u/mkoeppe/sage__n__warn_the_user_if_user_configuration_shadows_our_kernels

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

b4e7895

src/bin/sage-notebook, src/sage/repl/ipython_kernel/install.py: Check that the [SageMath](../wiki/SageMath) kernel can be discovered

[sagetrac-git]

Commit: b4e7895

[mkoeppe]

Author: Matthias Koeppe

[mkoeppe]

comment:6

(not really tested yet)

[kwankyu]

Changed commit from b4e7895 to 0add420

[kwankyu]

New commits:

0add420

Some edits

[kwankyu]

Changed branch from u/mkoeppe/sage__n__warn_the_user_if_user_configuration_shadows_our_kernels to public/33651

[kwankyu]

Reviewer: Kwankyu Lee

[kwankyu]

comment:8

Minor edits.

With my limited tests, it works well. I am positive.

[kwankyu]

Changed reviewer from Kwankyu Lee to Kwankyu Lee, ...

[mkoeppe]

Changed author from Matthias Koeppe to Matthias Koeppe, Kwankyu Lee

[mkoeppe]

Changed reviewer from Kwankyu Lee, ... to Kwankyu Lee, Matthias Koeppe

[vbraun]

Changed branch from public/33651 to 0add420