Package: check-python-versions
This is a tool for Python package maintainers who want to explicitly state
which Python versions they support.The problem: to properly support e.g. Python 2.7 and 3.6+ you have to
run tests with these Pythons.  This meansyou need a tox.ini with envlist = py27, py36, py37, py38, py39you need a .travis.yml with python: [ 2.7, 3.6, 3.7, 3.8, 3.9 ]if you support Windows, you need an appveyor.yml with %PYTHON% set to
C:\Python2.7, C:\Python3.5, and so onif you’re building manylinux wheels you need to … you get the ideayou have to tell the users which Python versions you support by specifying
trove classifiers like “Programming Language :: Python :: 2.7”you probably also want to tell pip which versions you support by specifying
python_requires=”>= 2.7, !=3.0.* …” because AFAIU PyPI classifiers are
not fine-grained enoughKeeping all these lists consistent is a pain.The solution:check-python-versionswill compare these lists and warn
you if they don’t match$ check-python-versions ~/projects/*
/home/mg/projects/check-manifest:

setup.py says:              2.7, 3.6, 3.7, 3.8, 3.9, PyPy
- python_requires says:     2.7, 3.6, 3.7, 3.8, 3.9
tox.ini says:               2.7, 3.6, 3.7, 3.8, 3.9, PyPy, PyPy3
.travis.yml says:           2.7, 3.6, 3.7, 3.8, 3.9, PyPy, PyPy3
appveyor.yml says:          2.7, 3.6, 3.7, 3.8, 3.9


/home/mg/projects/dozer:

setup.py says:              2.7, 3.6, 3.7, 3.8, 3.9
tox.ini says:               2.7, 3.6, 3.7, 3.8, 3.9
.travis.yml says:           2.7, 3.6, 3.7, 3.8, 3.9
appveyor.yml says:          2.7, 3.6, 3.7, 3.8, 3.9


/home/mg/projects/eazysvn:

setup.py says:              2.7, 3.6, 3.7, 3.8, 3.9, PyPy
tox.ini says:               2.7, 3.6, 3.7, 3.8, 3.9, PyPy, PyPy3
.travis.yml says:           2.7, 3.6, 3.7, 3.8, 3.9, PyPy, PyPy3
appveyor.yml says:          2.7, 3.6, 3.7, 3.8, 3.9

...

all ok!InstallationYou need Python 3.6 or newer (f-strings!) to run check-python-versions.
Install it withpython3 -m pip install check-python-versionsUsage$ check-python-versions --help
usage: check-python-versions [-h] [--version] [--expect VERSIONS]
                             [--skip-non-packages] [--only FILES]
                             [--add VERSIONS] [--drop VERSIONS]
                             [--update VERSIONS] [--diff] [--dry-run]
                             [where [where ...]]

verify that supported Python versions are the same in setup.py, tox.ini,
.travis.yml and appveyor.yml

positional arguments:
  where                directory where a Python package with a setup.py and
                       other files is located

optional arguments:
  -h, --help           show this help message and exit
  --version            show program's version number and exit
  --expect VERSIONS    expect these versions to be supported, e.g. --expect
                       2.7,3.5-3.8
  --skip-non-packages  skip arguments that are not Python packages without
                       warning about them
  --only FILES         check only the specified files (comma-separated list,
                       e.g. --only tox.ini,appveyor.yml)

updating supported version lists (EXPERIMENTAL):
  --add VERSIONS       add these versions to supported ones, e.g --add 3.9
  --drop VERSIONS      drop these versions from supported ones, e.g --drop
                       2.6,3.4
  --update VERSIONS    update the set of supported versions, e.g. --update
                       2.7,3.5-3.9
  --diff               show a diff of proposed changes
  --dry-run            verify proposed changes without writing them to diskIf run without any arguments, check-python-versions will look for a setup.py in
the current working directory.Exit status is 0 if all Python packages had consistent version numbers (and, if
–expect is specified, those numbers match your stated expectations).If you specify multiple directories on the command line, then all packages
that failed a check will be listed at the end of the run, separated with
spaces, for easier copying and pasting onto shell command lines.  This is
helpful when, e.g. you want to runcheck-python-versions ~/src/zopefoundation/*to check all 380+ packages, and then want re-run the checks only on the failed
ones, for a faster turnabout.There’s also experimental support for updating supported Python versions
so you can do things likecheck-python-versions ~/projects/* --add 3.9 --dry-run --expect 2.7,3.6-3.9
check-python-versions ~/projects/* --drop 3.4 --diff
check-python-versions ~/projects/* --update 2.7,3.6- --dry-run --diff
check-python-versions ~/projects/* --add 3.9 --drop=-2.6,-3.5(the last one will show a diff for each file and ask for interactive
confirmation before making any changes.)Programmatically updating human-writable files is difficult, so expect
bugs (and please file issues).Filessetup.pyorpyproject.tomlis the only required file; if any of the
others are missing, they’ll be ignored (and this will not be considered a
failure).setup.py: theclassifiersargument passed tosetup()is expected
to have classifiers of the form:classifiers=[
    ...
    "Programming Language :: Python :: x.y",
    ...
],check-python-versions will attempt to parse the file and walk the AST to
extract classifiers, but if that fails, it’ll executepython setup.py--classifiersand parse the output.There’s rudimentary support for dynamically-computed classifiers if at
least one part is a list literal, e.g. this can work and can even be
updatedclassifiers=[
    ...
    "Programming Language :: Python :: x.y",
    ...
] + ... expression that computes extra classifiers ...,setup.py: thepython_requiresargument passed tosetup(), if
present:python_requires=">=2.7, !=3.0.*, !=3.1.*",check-python-versions will attempt to parse the file and walk the AST to
extract thepython_requiresvalue.  It expects to find a string literal
or a simple expression of the form"literal".join(["...","..."]).pyproject.toml: can have any of these:# PEP 621 static metadata

[project]
classifiers = [
    ...
    "Programming Language :: Python :: 3.8",
    ...
]
requires-python = ">= 3.8"

# old-style Flit metadata

[tool.flit.metadata]
classifiers = [
    ...
    "Programming Language :: Python :: 3.8",
    ...
]
requires-python = ">= 3.8"

# Poetry metadata

[tool.poetry]
classifiers = [
    ...
    "Programming Language :: Python :: 3.8",
    ...
]

[tool.poetry.dependencies]
python = "^3.8"tox.ini: if present, it’s expected to have[tox]
envlist = pyXY, ...Environment names like pyXY-ZZZ are also accepted; the suffix is ignored..travis.yml: if present, it’s expected to havepython:
  - X.Y
  - ...and/ormatrix:
  include:
    - python: X.Y
      ...
    - ...and/orjobs:
  include:
    - python: X.Y
      ...
    - ...and/orenv:
  - TOXENV=...(but not all of these forms are supported for updates)appveyor.yml: if present, it’s expected to haveenvironment:
  matrix:
    - PYTHON: C:\\PythonX.Y
    - ...The environment variable name is assumed to bePYTHON(case-insensitive).
The values should be one ofX.YC:\\PythonX.Y(case-insensitive)C:\\PythonX.Y-x64(case-insensitive)Alternatively, you can useTOXENVwith the usual values (pyXY).(TOXENVis currently not supported for updates.).manylinux-install.sh: if present, it’s expected to contain a loop likefor PYBIN in /opt/python/*/bin; do
    if [[ "${PYBIN}" == *"cp27"* ]] || \
       [[ "${PYBIN}" == *"cp35"* ]] || \
       [[ "${PYBIN}" == *"cp36"* ]] || \
       [[ "${PYBIN}" == *"cp37"* ]] || \
       [[ "${PYBIN}" == *"cp38"* ]]; then
        "${PYBIN}/pip" install -e /io/
        "${PYBIN}/pip" wheel /io/ -w wheelhouse/
           rm -rf /io/build /io/*.egg-info
    fi
donecheck-python-versions will look for $PYBIN tests of the form[[ "${PYBIN}" == *"cpXY"* ]]where X and Y are arbitrary digits.These scripts are used in several zopefoundation repositories like
zopefoundation/zope.interface.  It’s the least standartized format..github/workflows/*.yml: if present, it’s expected to havejobs:
  (anything):
    strategy:
      matrix:
        python-version:
          - X.Y
          - ...orjobs:
  (anything):
    strategy:
      matrix:
        config
          - [ X.Y, "pyXY" ]
          - ...Python versionsIn addition to CPython X.Y, check-python-versions will recognize PyPy and PyPy3
in some of the files:setup.pyorpyproject.tomlmay have a'Programming Language :: Python :: Implementation :: PyPy',classifiertox.inimay have pypy[-suffix] and pypy3[-suffix] environments.travis.ymlmay have pypy and pypy3 jobs with optional version suffixes
(e.g. pypy2.7-6.0.0, pypy3.5-6.0.0).github/workflows/*.yml: may have pypy/pypy3/pypy-N.M/pypy-N.M-vX.Y.Z
jobs.appveyor.ymland.manylinux-install.shdo not usually have pypy tests,
so check-python-versions cannot recognize them, and these files are excluded
from PyPy support consistency checks.Upcoming Python releases (such as 3.12 in setup.py or 3.12-dev in a .travis.yml)
are also shown but do not cause mismatch errors.In addition,python_requiresin setup.py orrequires-pythonin
pyproject.toml usually has a lower limit, but no upper limit.
check-python-versions will assume this means support up to
whatever’s the latest Python 3.x release mentioned in other data sources, or
the current 3.x release (3.11 at the moment), whichever is lower.  This means
that new Python 3 releases don’t suddenly cause all your lint checks to fail
if you use python_requires ‘>= 3.6’ and such.When you’re specifying Python version ranges for –expect, –add, –drop or
–update, you can useX.Y(e.g.--add3.8)X.Y-U.Vfor an inclusive range (e.g.--add3.5-3.8)X.Y-, which means from X.Y until the latest known release from the X
series (e.g.--add3.5-is equivalent to--add3.5-3.7)-X.Y, which is the same asX.0-X.Y(e.g.--drop-3.4is equivalent to--drop3.0-3.4)or a comma-separated list of the above (e.g.--expect2.7,3.5-,--drop-2.6,-3.4).–expect/–add/–drop/–update currently do not allow specifying alternative
implementations (such as pypy).pre-commit integrationWithpre-commit,check-python-versionscan be part of your git-workflow.
Add the following snippet to your.pre-commit-config.yaml.repos:-repo:https://github.com/mgedmin/check-python-versionsrev:"0.22.0"hooks:-id:check-python-versions