RFC: Apply REUSE recommendations for license tagging

[Flameeyes]

The REUSE specifications are a suggestion coming from FSFE to make code licensing information explicit and easier to apply. They build upon SPDX Tags to make it obvious (and at the same time less verbose) which license apply to a certain work: code, documentation, examples, etc.

I have been suggesting its use and using it for my own projects, and I feel it would be a positive change for CircuitPython's examples in particular, as right now the easiest way to find which license they are released upon is to trust the repository-wide LICENSE file (rather than just looking at the snippets in the documentation.)

In addition to specifying how to tag the licensing, the reuse tool is designed to aid adding the tags, and to validate the repository compliance to those specifications. Its linting mode can be integrated with both pre-commit and with other CI tooling.

Because I was a bit over eager to help with this one, I already have a pull request that can show how this would look like for the repositories: adafruit/Adafruit_CircuitPython_ESP32SPI#99

In that pull request there's a few rough edges:

• All the code (and documentation) that otherwise didn't have an explicit license headers have been tagged with @ladyada's copyright as per the LICENSE file.
• The favicon.ico file has been tagged with MIT license and the same copyright information. I do believe this is incorrect, and would like to know what the correct information should be.
• All configuration files have been tagged with ladyada's copyright and Unlicense. The current REUSE recommendation is to use CC0-1.0, but that has… side effects. There's some discussion in
  Alter CC0-1.0 recommendation for uncopyrightable files fsfe/reuse-docs#62 about the recommendation for likely-uncopyrightable files (such as configuration files).

[tannewt]

I think it's a good idea.

Would you mind updating our test repo including the CI checks? https://github.com/adafruit/Adafruit_CircuitPython_TestRepo

The step after that would be to update the cookiecutter: https://github.com/adafruit/cookiecutter-adafruit-circuitpython/

[Flameeyes]

Oh that cookiecutter looks nice!

Sure I'll prepare a pull request for testrepo — there's at least one question that stays open though: what's the license of the logo? (In the favicon.ico)

[tannewt]

The logo is CC-BY 4.0: https://www.dropbox.com/sh/l6tp9ym5nf8h5v9/AABGu_q2pcdUQdx1avr8Xvvda?dl=0&preview=license-readme.txt

It's worth noting that the copyright license on the logo doesn't override the limitations of using it because of Adafruit's trademark.

[dhalbert]

@ladyada Do you or PT or your lawyers have an opinion on this? Also see
adafruit/Adafruit_CircuitPython_TestRepo#33
adafruit/actions-ci-circuitpython-libs#8

[ladyada]

this is fine, please merge when ready and we'll keep an eye on it

[Flameeyes]

To sum up current state:

• Apply SPDX copyright and license headers in compliance with REUSE. actions-ci-circuitpython-libs#8 is needed to make pre-commit run --all-files pass when running as part of the CI;
• once that's merged, Example implementation of REUSE specifications. Adafruit_CircuitPython_TestRepo#33 should pass CI and be ready to merge.

Should I wait for both to be merged before preparing the equivalent change for https://github.com/adafruit/cookiecutter-adafruit-circuitpython/, so we know what the final form of it should be?

[tannewt]

@Flameeyes you are welcome to make the PR. we won't want to merge until it'll be green.

[dhalbert]

• adafruit/actions-ci-circuitpython-libs#8 is needed to make pre-commit run --all-files pass when running as part of the CI;
• once that's merged, adafruit/Adafruit_CircuitPython_TestRepo#33 should pass CI and be ready to merge.

Both of these are now approved and merged.

[Flameeyes]

Here's the cookiecutter PR: adafruit/cookiecutter-adafruit-circuitpython#75

There's probably more opportunities for templating the copyright for the generated repository, do let me know if you notice any.

[Flameeyes]

Current status:

• cookiecutter PR needs review
• https://github.com/adafruit/Adafruit_CircuitPython_ESP32SPI/pull/99/commits (the original RFC pull request) is updated to match the changes for TestRepo, including the updated code of conduct file, and the correct licensing for the favicon.

[tannewt]

@Flameeyes Thanks for this work! I've merged both of these PRs and replied on the CircuitPython pre-commit PR.

[dhalbert]

Note that in order to reduce skew from MicroPython, which does not use SPDX tags, we have removed SPDX from core files we inherit from MicroPython.