For reasons that at-present escape me, pipenv insists on creating a stub
pyproject.toml file. This file is a nuisance, because its mere presence
changes the behavior of various tools.

For instance, this stub file will cause "pip install --user -e ." to
fail in spectacular fashion with misleading errors. "pip install -e ."
works okay, but for some reason pip does not support editable installs
to the user directory when using PEP517.

References:
  https://github.com/pypa/pip/pull/9990
  https://github.com/pypa/pip/issues/7953



As outlined in ea1213b7, it is still too early for us to consider
moving to a PEP-517 exclusive package. We must support older
distributions, so squash the annoyance for now. (Python 3.6 shipped Dec
2016, PEP517 support showed up in pip sometime in 2019 or so.)

Add 'pyproject.toml' to the 'make clean' target, and also delete it
after every pipenv invocation issued by the Makefile.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-id: 20210629214323.1329806-15-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

Update for visual parity with all the remaining targets.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-id: 20210629214323.1329806-14-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

Update for visual parity with the other targets.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-id: 20210629214323.1329806-13-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

This is a *third* way to run the Python tests. Unlike the first two
(check-pipenv, check-tox), this version does not require any specific
interpreter version -- making it a lot easier to tell people to run it
as a quick smoketest prior to submission to GitLab CI.

Summary:

  Checked via GitLab CI:
    - check-pipenv: tests our oldest python & dependencies
    - check-tox: tests newest dependencies on all non-EOL python versions
  Executed only incidentally:
    - check-dev: tests newest dependencies on whichever python version

('make check' does not set up any environment at all, it just runs the
tests in your current environment. All four invocations perform the
exact same tests, just in different execution environments.)

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Tested-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-id: 20210629214323.1329806-12-jsnow@redhat.com
[Maintainer edit: added .dev-venv/ to .gitignore. --js]
Acked-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Acked-by: Willian Rampazzo <willianr@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>

I missed the 'check-tox' target. Add that, but split the large .PHONY
specifier at the top into its component pieces and move them near the
targets they describe so that they're much harder to forget to update.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-id: 20210629214323.1329806-10-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

Move it up near the check-pipenv help text, and update it to suggest parity.

(At the time I first added it, I wasn't sure if I would be keeping it,
but I've come to appreciate it as it has actually helped uncover bugs I
would not have noticed without it. It should stay.)

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-id: 20210629214323.1329806-9-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

Well, Cleber was right, this is a better name.

In preparation for adding a different kind of virtual environment check
(One that simply uses whichever version of Python you happen to have),
rename this test 'check-pipenv' so that it matches the CI job
'check-python-pipenv'.

Remove the "If you don't know which test to run" hint, because it's not
actually likely you have Python 3.6 installed to be able to run the
test. It's still the test I'd most prefer you to run, but it's not the
test you are most likely to be able to run.

Rename the 'venv' target to 'pipenv' as well, and move the more
pertinent help text under the 'check-pipenv' target.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-id: 20210629214323.1329806-8-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

This is intended to be a manually run, non-CI script.

Use tox to test the linters against all python versions from 3.6 to
3.10. This will only work if you actually have those versions installed
locally, but Fedora makes this easy:

> sudo dnf install python3.6 python3.7 python3.8 python3.9 python3.10

Unlike the pipenv tests (make venv-check), this pulls "whichever"
versions of the python packages, so they are unpinned and may break as
time goes on. In the case that breakages are found, setup.cfg should be
amended accordingly to avoid the bad dependant versions, or the code
should be amended to work around the issue.

With confidence that the tests pass on 3.6 through 3.10 inclusive, add
the appropriate classifiers to setup.cfg to indicate which versions we
claim to support.

Tox 3.18.0 or above is required to use the 'allowlist_externals' option.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Tested-by: Cleber Rosa <crosa@redhat.com>
Message-id: 20210527211715.394144-31-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

Add "make venv" to create the pipenv-managed virtual environment that
contains our explicitly pinned dependencies.

Add "make check" to run the python linters [in the host execution
environment].

Add "make venv-check" which combines the above two: create/update the
venv, then run the linters in that explicitly managed environment.

Add "make develop" which canonizes the runes needed to get both the
linting pre-requisites (the "[devel]" part), and the editable
live-install (the "-e" part) of these python libraries.

make clean: delete miscellaneous python packaging output possibly
created by pipenv, pip, or other python packaging utilities

make distclean: delete the above, the .venv, and the editable "qemu"
package forwarder (qemu.egg-info) if there is one.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Tested-by: Cleber Rosa <crosa@redhat.com>
Message-id: 20210527211715.394144-29-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>