Fix packaging

[rpkilby]

I've punted on moving the package under a src directory, and just made the minimum necessary changes. Also, fixes #5615.

---

I don't know if we want to accept this as is, given that I moved the package contents into a src directory. If we're willing to accept that change, the move is for a good reason. tox does create and install the package distribution into the test environment, however this conflicts with the rest_framework package that's located on the current path. Because the distribution and local files conflict, you cannot effectively test the distribution's packaged files. eg, the distribution may not be correctly configured (missing templates/static files), but the files on the local path do have them, so the tests pass erroneously.

The solution is to move the package off of the path (usually into a src directory), so that the local files are not importable.

The alternative would be to not move the package into src and accept that we may accidentally leave out files from time to time. This is probably fine, given that the manifest won't change very often.

[auvipy]

what benefit will be added by moving under src/ ?

will that create any backward incompatibility?

[rpkilby]

@auvipy. The core issue is that tox, while it does create and install a distribution for DRF, the files in the distribution conflict with those found on the local path. This is usually fine, however, it prevents you from finding packaging issues. eg, your distribution may be borked (missing templates and static files), but testing passes erroneously because it can find these files under the local path. By moving the package on the local path into a src directory, they're no longer directly importable (and as a side effect, the templates/static files are no longer found). Thus, tox is just testing the distribution, so you have better assurance that your distribution is correct.

[rpkilby]

As to backward incompatibility, there shouldn't be any issues. At the end of the day, the distribution still contains a single rest_framework package. The only potential issues would be files missing from the distribution due to misconfiguration. Although, that's what this PR aims to fix by moving the package into a src directory.

[xordoquy]

I don't think there'll be issue since it's just about the repository layout.
I'm ok with the overall idea.

[rpkilby]

I'd rather punt on moving the package under a src directory for now. It creates issues with the coverage report, as the files are no longer under rest_framework, but under site-packages in the test env.

---

Notes to future myself about moving the package under src:

• tox testenvs should use the usedevelop option, as opposed to installing a competing sdist. This keeps the coverage data from breaking.
• to test the packaging, specifically add a dist testenv. It's not necessary to test the dist against every testenv in the matrix.

[carltongibson]

OK. This looks good. (And fixes #5615! 🙂)

[tomchristie]

Nice work!

[ryanhiebert]

I'd rather punt on moving the package under a src directory for now. It creates issues with the coverage report, as the files are no longer under rest_framework, but under site-packages in the test env.

This is something I had to overcome with tox-travis as well. It manages it by running coverage in parallel mode, then combining paths to be the files in the src directory. It can be a little confusing to figure out where the lines should be on using combine, etc, but it does seem to work get the job done in my experience.

I'm not sure how much tox-travis has informed your knowledge here, but I do think that I got it worked out OK there. You can check out what I did in the tox-travis tox.ini file for the coverage configuration.

[rpkilby]

Thanks @ryanhiebert. I was able to get coverage to work properly in #5656, but moving the package into a src directory was decided against. Instead there's a single build that tests the packaging w/o coverage.