PEP 639: Use SPDX license expressions in Core package metadata (#1625)

* Add PEP draft for SPDX license expressions

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Add reference to another license-related ticket

pypa/packaging-problems#41

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Add proper Draft status

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Direct PEP discussions to discuss.python.org

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Adopt latest PEP copyright conventions

Reported-by: Aliaksei Urbanski @Jamim
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Add @pf_moore as BDFL delegate.

And fix minor typo

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Add Paul Moore as a PEP sponsor

CC: @pfmoore
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Reuse License Field. Add License-File.

Do not deprecate the License field with a new field. Instead reuse
License and provide backward compatibility.

Also add License-File field already in use in wheel and setuptools.

Integrates latest feedback

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Add packaging license metadata survey sections

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Add poetry and flit references

CC: @takluyver and @sdispater
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Fix typo

Reported-by: Pradyun Gedam @pradyunsg
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Co-Authored-By: Pradyun Gedam <pradyunsg@gmail.com>

* Fix typo and improve subtitle

Reported-by: Pradyun Gedam <pradyunsg@gmail.com>
Co-Authored-By: Pradyun Gedam <pradyunsg@gmail.com>
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Fix typo

Reported-by: Pradyun Gedam <pradyunsg@gmail.com>
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Co-Authored-By: Pradyun Gedam <pradyunsg@gmail.com>

* Fix typo

Reported-by: Pradyun Gedam <pradyunsg@gmail.com>
Co-Authored-By: Pradyun Gedam <pradyunsg@gmail.com>
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Use appendix and use footnotes for links

Also improve formatting

Reported-by: Pradyun Gedam @pradyunsg
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Add new sections and improve existing sections

- Refactor intro with new and improved abstract, scope, non-scope,
motivation and rationale sections
- Add new Backwards Compatibility, Security and How to Teach sections
- Move Reference Implementation out of appendix as its own section
- Add new Rejected ideas section
- Add new License Expression example using setuptools in Appendix

Reported-by: Chris Jerdonek @cjerdonek
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Fix typo

Reported-By: Pradyun Gedam <pradyunsg@gmail.com>
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Co-Authored-By: Pradyun Gedam <pradyunsg@gmail.com>

* Fix typo

Reported-By: Pradyun Gedam <pradyunsg@gmail.com>
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Co-Authored-By: Pradyun Gedam <pradyunsg@gmail.com>

* Improve presentation

Reported-By: Pradyun Gedam <pradyunsg@gmail.com>
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Co-Authored-By: Pradyun Gedam <pradyunsg@gmail.com>

* Improve style

Reported-By: Pradyun Gedam <pradyunsg@gmail.com>
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Co-Authored-By: Pradyun Gedam <pradyunsg@gmail.com>

* Move setuptools and wheel notes on license-file out

Reported-by: Nick Coghlan @ncoghlan
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Clarify and discourage use of public domain

Reported-by: Nick Coghlan @ncoghlan
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Fix typo

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Fix typos and clarify multi classifiers migrations

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Report warning for expression case

The case does nt matter, but there is a canonical case: if the case
is the not the standard canonical case, tools should issue a warning.

Reported-by: Oleg Grenrus @phadej
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Use deprecated not obsolete per SPDX

Reported-by: Oleg Grenrus @phadej
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Correct Cabal that uses SPDX expressions

Cabal uses both expressions and license files as proposed in this PEP

Reported-by: Oleg Grenrus @phadej
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Fix typo

Reported-by: Oleg Grenrus @phadej
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Use LicenseRef- prefix for non-standard SPDX ids

This help endsure that the expressions is fully parseable by a
conforming license expression processor

Reported-by: Oleg Grenrus @phadej
Reported-by: Nick Coghlan @ncoghlan
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Fix typos.

Reporte-by: Cyril Roelandt <tipecaml@gmail.com>
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Fix typo and add BSD* distributions reference


Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Fix typo and improve grammar


Reported-by: Nick Coghlan @ncoghlan
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Copy Edits for initial sections

* Reword a paragraph

* Update pep-9999.rst

* Fix typo


Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Remove erroneous leading spaces

Reported-by: Pradyun Gedam @pradyunsg
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Co-authored-by: Pradyun Gedam <pradyunsg@gmail.com>

* Update SPDX license list and spec versions

Use latest SPDX spec 2.2 and SPDX license list 3.10

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Fix typos and formatting

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Clarify License file path definition

Reported-by: Miro Hrončok @hroncok
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Use permalink for discussion link

Reported-by: Tzu-ping Chung @uranusjr
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

* Assign number as PEP-0639

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Co-authored-by: Pradyun Gedam <pradyunsg@gmail.com>

Author: pombredanne