The PEP 517 shows an example backend-path like this:
[build-system]
# Defined by PEP 518:
requires = ["flit"]
# Defined by this PEP:
build-backend = "local_backend"
backend-path = ["backend"]
https://www.python.org/dev/peps/pep-0517/#source-trees
See that backend-path is a list. Our code previously only supported string path.
Obviously a string path is wrong, but we keep it to support projects that have
made the mistake, such as flit-core.
Add a small integration test for both cases.
Note that the new spec files deliberately don't do much, to save CI time.
An empty line happens when there are not deps:
Handling from tox --print-deps-only: <toxname>
WARNING: Skipping invalid requirement:
Parse error at "''": Expected W:(abcd...)
If not checked, installing runtime requirements might fail.
When a requirement is specified in setuptools' setup_requires:
setup(
...
setup_requires=["pytest-runner"],
)
It is part of the get_requires_for_build_wheel hook output.
When runtime requirements are parsed with setuptools without all setup_requires
present, it tries to get them from the internet (at least on Fedora 33).
By checking the requirements after installing "requires_for_build_wheel",
we make sure all setup_requires are already installed.
When runtime requirements are not installed, this adds an unneeded check,
but the script would end at that point anyway, so there is no real difference.
This change introduces code from pyreq2rpm, a tested set of
requirement conversion functions used in pyp2rpm and rpm's
pythondistdeps.
This adds support for the '~=' operator and wildcards.
Pros:
- projects without pyproject.toml will have 1 less dependency
- toml will be buildable with pyproject-rpm-macros out of the box
- easier bootstrap sequence (in theory)
Cons:
- projects with pyproject.toml will have 1 more %generate_buildrequires round
There is a slight problem when reporting that a dependency with extra is satisfied.
In fact, we only check the "base" dependency.
This can lead to a problem when a dependency is wrongly assumed as present
and the script proceeds to the "next stage" without restarting --
if the next stage tries to use (import) the missing dependency,
the script would crash.
However, that might be a very unlikely set of events and if such case ever happens,
we'll workaround it or fix it.
Falling back to setuptools.build_meta:__legacy__ is the standard behavior,
not setuptools.build_meta. See PEP 517:
https://www.python.org/dev/peps/pep-0517/
> If the pyproject.toml file is absent, or the build-backend key is missing,
> the source tree is not using this specification, and tools should revert
> to the legacy behaviour of running setup.py (either directly, or by
> implicitly invoking the setuptools.build_meta:__legacy__ backend).
Falling back to setuptools.build_meta had very similar results so far.,
but the behavior might change in the feature.
While working on this, I have uncovered a problem in our code.
It was not able to handle backends with ":". Looking at PEP 517 again:
> build-backend is a string naming a Python object that will be used to
> perform the build. This is formatted following the same module:object syntax
> as a setuptools entry point. For instance, if the string is "flit.api:main",
> this object would be looked up by executing the equivalent of:
>
> import flit.api
> backend = flit.api.main
>
> It's also legal to leave out the :object part, e.g.
>
> build-backend = "flit.api"
>
> which acts like:
>
> import flit.api
> backend = flit.api
We now handle such cases properly. Witch the change of the default backend,
we also test a backend with colon in our tests.
Previously, it wasn't possible to see why tox failed:
...
Requirement satisfied: tox-current-env >= 0.0.2
(installed: tox-current-env 0.0.2)
Traceback (most recent call last):
File "/usr/lib/rpm/redhat/pyproject_buildrequires.py", line 269, in main
generate_requires(
File "/usr/lib/rpm/redhat/pyproject_buildrequires.py", line 221, in generate_requires
generate_tox_requirements(toxenv, requirements)
File "/usr/lib/rpm/redhat/pyproject_buildrequires.py", line 184, in generate_tox_requirements
r = subprocess.run(
File "/usr/lib64/python3.8/subprocess.py", line 512, in run
raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['tox', '--print-deps-to-file', '/tmp/tmp96smu4rv', '-qre', 'py38']' returned non-zero exit status 1.
Now it is:
...
Requirement satisfied: tox-current-env >= 0.0.2
(installed: tox-current-env 0.0.2)
ERROR: tox config file (either pyproject.toml, tox.ini, setup.cfg) not found
Traceback (most recent call last):
File "/usr/lib/rpm/redhat/pyproject_buildrequires.py", line 270, in main
generate_requires(
File "/usr/lib/rpm/redhat/pyproject_buildrequires.py", line 222, in generate_requires
generate_tox_requirements(toxenv, requirements)
File "/usr/lib/rpm/redhat/pyproject_buildrequires.py", line 193, in generate_tox_requirements
r.check_returncode()
File "/usr/lib64/python3.8/subprocess.py", line 444, in check_returncode
raise CalledProcessError(self.returncode, self.args, self.stdout,
subprocess.CalledProcessError: Command '['tox', '--print-deps-to-file', '/tmp/tmpwp8sffv1', '-qre', 'py38']' returned non-zero exit status 1.
Inspired by https://src.fedoraproject.org/rpms/python-chaospy/pull-request/1#comment-32750
