Use explicit config files for black and isort

[danielmitterdorfer]

Using pyproject.toml for black and isort configuration has unwanted
side effects when Rally is installed in certain environments (and in
editable mode). While this should be addressed at a later point because
editable mode is about to removed anyway (see PEP-517 and PEP-518) we
will use explicitly specified config files for now.

Relates #1281
Relates pypa/pip#6433

[dliappis]

LGTM thank you

[pquentin]

Can you please clarify what the unwanted side effects are?

The problem with a black.toml file is that my editor won't see it, so I'd suggest renaming that file back to pyproject.toml (and still specifiy it explicitly if that helps).

[danielmitterdorfer]

Can you please clarify what the unwanted side effects are?

We have some internal tooling, for example to run our nightly benchmarks, that builds on top of Rally. It installs Rally master in editable mode. Due to the presence of pyproject.toml, pip started to prefer that file to setup.py and caused build failures (example).

There is definitely room for improvement in how we setup Rally in these scenarios but the most pragmatic solution to unblock us for now was to explicitly configure black and isort via dedicated config files so the current mechanism still works.

[pquentin]

Thanks. I believe those lines in pyproject.toml are enough to fix the issue:

[build-system]
requires = ["setuptools >= 40.6.0", "wheel"]
build-backend = "setuptools.build_meta"

But I can't reproduce so I'm not sure. Is there a simple way to see if that fixes the issue?