pkgs/sagemath-standard: Remove self-reference at build time

[mkoeppe]

As explained in #37287 (comment), we make sagemath-environment a build requirement of pkgs/sagemath-standard.

The monolithic build system in SAGE_ROOT/src is left unchanged.

📝 Checklist

• The title is concise, informative, and self-explanatory.
• The description explains in detail what this PR is about.
• I have linked a relevant issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation accordingly.

⌛ Dependencies

• Depends on README.md: Improve PyPI install instructions #37261
• Depends on setup.py: Remove lazy_import_cache use #37432
• Depends on Document building from the monorepo using PIP_CONSTRAINT=$SAGE_ROOT/constraints_pkgs.txt #37434
• Depends on doing something about this kernelspec install thing
• Depends on build/pkgs/sagemath_{categories,environment,objects,repl}: Change to optional #38200

[github-actions]

Documentation preview for this PR (built with commit 8a09d7c; changes) is ready! 🎉

[tobiasdiez]

With these changes, how do you pip install the monolithic sagelib (ie the one independent of any modularized distributions)?

[mkoeppe]

With these changes, how do you pip install the monolithic sagelib

There is no change regarding this.

[tobiasdiez]

With these changes, how do you pip install the monolithic sagelib

There is no change regarding this.

It seems that only pkgs/sagemath-standard is published on pypi, not the one in src. And since you break the smylink it now matters.

[mkoeppe]

pkgs/sagemath-standard is published on pypi

That's right.

it now matters.

What matters?

[tobiasdiez]

It matters for the following. Right now it is possible to install the monolithic sagelib distribution via pip, with your changes this is no longer possible.

With these changes, how do you pip install the monolithic sagelib

There is no change regarding this.

[mkoeppe]

Right now it is possible to install the monolithic sagelib distribution via pip, with your changes this is no longer possible.

Nonsense.

[mkoeppe]

@kiwifb Please review

[kiwifb]

Looks good to me. It will not change anything from the sdist point of view as far as I can tell. If we are going to split things, I certainly want us to eat our own dog food and see stuff like pyproject-monolithic.toml.m4 going out as quickly as possible.

[mkoeppe]

It will not change anything from the sdist point of view as far as I can tell.

That's right, avoiding the self-ref is just a cleanup.

[tobiasdiez]

Right now it is possible to install the monolithic sagelib distribution via pip, with your changes this is no longer possible.

Nonsense.

You then might want to explain how a user would install it then from pypi (that you can still checkout the code and use the pyproject.toml from src is obvious).

[mkoeppe]

#37261 has updated the PyPI install instructions in our README.md, waiting for review.

I'll mark it as a dependency