Install Jupyter kernel in the correct prefix

[jdemeyer]

The Sage Jupyter kernel is unconditionally installed in sys.prefix. However, this should instead be the install_data directory. This defaults to the installation prefix, which in turn defaults to sys.prefix. So the default won't change, but it allows customization.

The reason for choosing install_data is to be compatible with other Jupyter packages, which use the data_files option to setup() for installing Jupyter files (see for example https://github.com/jupyter-widgets/ipywidgets/blob/master/widgetsnbextension/setup.py#L203).
Those files are installed in the install_data directory.

CC: @timokau @kiwifb

Component: distribution

Author: Jeroen Demeyer

Branch/Commit: ad0ee29

Reviewer: Vincent Klein

Issue created by migration from https://trac.sagemath.org/ticket/25546

[jdemeyer]

Branch: u/jdemeyer/ticket/25546

[jdemeyer]

Commit: ad0ee29

[jdemeyer]

New commits:

ad0ee29

Install Jupyter kernel in install_data directory

[kiwifb]

comment:4

That looks like it may greatly simplify my life. I have still one issue about the current setup but it is comparatively minor - I think the code installing the kernel should live under sage_setup since you are not supposed to use it at runtime. But that can wait.

[timokau]

comment:5

What is the install_data directory? Is that variable documented somewhere?

[kiwifb]

comment:6

Replying to @timokau:

What is the install_data directory? Is that variable documented somewhere?

It's a standard distutils command it is mentioned on this page for example https://wiki.python.org/moin/Distutils/Tutorial.

[jdemeyer]

comment:8

Replying to @timokau:

What is the install_data directory? Is that variable documented somewhere?

I don't know whether it's documented, but it's the directory where data_files are installed. As I explained in the ticket description, it's certainly the right directory to use.

[jdemeyer]

comment:9

Replying to @kiwifb:

https://wiki.python.org/moin/Distutils/Tutorial.

I think that page takes about about install_data command, not the install_data directory.

[timokau]

comment:10

Replying to @jdemeyer:

Replying to @timokau:

What is the install_data directory? Is that variable documented somewhere?

I don't know whether it's documented, but it's the directory where data_files are installed. As I explained in the ticket description, it's certainly the right directory to use.

I can't even find the default value of that variable by grepping through the distutils source. However as long as it is relative to --prefix, thats fine by me and should solve #25328.

[vinklein]

comment:11

Tested. It works for me.

[vinklein]

Reviewer: Vincent Klein

[vbraun]

Changed branch from u/jdemeyer/ticket/25546 to ad0ee29