Modularization of sagelib: Create modular packages sage-core, sage-tdlib

[mkoeppe]

The new package sage-tdlib represents the old OptionalExtension sage.graphs.graph_decompositions.tdlib (building upon #29701, #28925). We use it as an example package for the modularization.

See build/pkgs/sage_tdlib/spkg-install for an overview of the intended implementation targeting Sage 9.3.

sage-core is a version of sagelib - as of this ticket, consisting of everything in sagelib except for sage.graphs.graph_decompositions.tdlib.

sage-core and sage_tdlib do not use the incremental install mechanism of sagelib (sage_setup.command.sage_install.sage_install_and_clean). They use a simple setuptools build system.

This is part of #29705: Meta-ticket: Modularize sagelib into separate distributions (distutils packages)

[mkoeppe]

Last 10 new commits:

​7dd469f	WIP: Add sage_tdlib package, use symlinks for sagelib package
​24e9b30	build/pkgs/sage_tdlib/src/MANIFEST.in: New
​9b59435	fixup symlinks
​c3593b2	build/pkgs/sage_tdlib/src/sage_setup: Remove, we use the installed one
​2612091	Use setup.py install --single-version-externally-managed
​458d851	build/pkgs/sage_tdlib/spkg-src: New
​5d4e8e7	build/pkgs/sage_tdlib/dependencies: Add sagelib, python toolchain
​7042564	build/pkgs/sagelib/spkg-src: New
​90b33d8	Install sagelib, sage_tdlib via sdist defined by MANIFEST.in
​2ccf6b7	Merge tag '9.2.beta1' into t/29705/META-modularize-sagelib

[gh-tobiasdiez]

Just for clarification, was is sage-lib and what sage-core?

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. Last 10 new commits:

​e8d1a23	src/setup.py: from setuptools import setup
​c99dab5	Add src/setup.cfg
​67189ba	WIP: Add sage_tdlib package, use symlinks for sagelib package
​5d85487	build/pkgs/sage_tdlib/src/MANIFEST.in: New
​bf5dddc	fixup symlinks
​6d5e4f5	build/pkgs/sage_tdlib/src/sage_setup: Remove, we use the installed one
​4cd5176	Use setup.py install --single-version-externally-managed
​577f338	build/pkgs/sage_tdlib/spkg-src: New
​8b972d7	build/pkgs/sage_tdlib/dependencies: Add sagelib, python toolchain
​bf1c011	Install sagelib, sage_tdlib via sdist defined by MANIFEST.in

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. Last 10 new commits:

​2e61ada	sage.numerical.backends: Make it a namespace package by removing __init__.py (which was empty)
​26b1ca0	Mark src and src/sage/ext_data as directories that are not namespace packages
​a733af5	sage_setup.find.find_python_sources: Handle native namespace packages, 'nonamespace' files
​c08c511	is_package_or_namespace_package_dir: New, recognize namespace packages by file 'namespace', monkeypatch into Cython
​4407e5e	sage_setup.command.sage_install.sage_install: Rename to sage_install_and_clean, update use it in src/setup.py; refactor through new class sage_install
​a13c126	Make sage.graphs, sage.matrix, sage.libs, sage.interfaces namespace packages
​a967aca	WIP
​c746965	sage_setup/command/sage_install.py: WIP: Disable cleaning
​6ba4212	WIP: Add sage_tdlib package, use symlinks for sagelib package
​59a33de	Install sagelib, sage_tdlib via sdist defined by MANIFEST.in