TypeError: 'digest_size' is an invalid keyword argument for openssl_blake2b()

Environment

1. Operating system:

RedHat Linux inside an UBI8 Python 3.9 container image.

1. Version of python you are running:

python --version
Python 3.9.6

1. How did you install twine? Did you use your operating system’s package manager or pip or something else?

Using tox, as follows, running tox -e readme:

[testenv:readme]
description = Ensure README renders on PyPI
deps =
    build
    twine
commands =
    {envpython} -m build
    {envpython} -m twine check dist/*

1. Version of twine you have installed (include complete output of):

twine --version
twine version 3.7.1 (importlib_metadata: 4.10.0, pkginfo: 1.8.2, requests:
2.27.1, requests-toolbelt: 0.9.1, tqdm: 4.62.3)

1. Other: (maybe relevant)

My pyproject.toml looks like this:

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

The Issue

...
readme run-test: commands[6] | /builds/devsecops/git-malware-scanner/.tox/readme/bin/python -m twine check 'dist/*'
Traceback (most recent call last):
  File "/usr/lib64/python3.9/runpy.py", line 197, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/usr/lib64/python3.9/runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "/builds/devsecops/git-malware-scanner/.tox/readme/lib/python3.9/site-packages/twine/__main__.py", line 53, in <module>
    sys.exit(main())
  File "/builds/devsecops/git-malware-scanner/.tox/readme/lib/python3.9/site-packages/twine/__main__.py", line 28, in main
    result = cli.dispatch(sys.argv[1:])
  File "/builds/devsecops/git-malware-scanner/.tox/readme/lib/python3.9/site-packages/twine/cli.py", line 71, in dispatch
    return main(args.args)
  File "/builds/devsecops/git-malware-scanner/.tox/readme/lib/python3.9/site-packages/twine/commands/check.py", line 191, in main
    return check(parsed_args.dists, strict=parsed_args.strict)
  File "/builds/devsecops/git-malware-scanner/.tox/readme/lib/python3.9/site-packages/twine/commands/check.py", line 135, in check
    warnings, is_ok = _check_file(filename, render_warning_stream)
  File "/builds/devsecops/git-malware-scanner/.tox/readme/lib/python3.9/site-packages/twine/commands/check.py", line 78, in _check_file
    package = package_file.PackageFile.from_filename(filename, comment=None)
  File "/builds/devsecops/git-malware-scanner/.tox/readme/lib/python3.9/site-packages/twine/package.py", line 128, in from_filename
    return cls(filename, comment, meta, py_version, dtype)
  File "/builds/devsecops/git-malware-scanner/.tox/readme/lib/python3.9/site-packages/twine/package.py", line 78, in __init__
    hasher = HashManager(filename)
  File "/builds/devsecops/git-malware-scanner/.tox/readme/lib/python3.9/site-packages/twine/package.py", line 261, in __init__
    self._blake_hasher = hashlib.blake2b(digest_size=256 // 8)
TypeError: 'digest_size' is an invalid keyword argument for openssl_blake2b()
Checking dist/git_malware_scanner-1.0.0-py3-none-any.whl: ERROR: InvocationError for command /builds/devsecops/git-malware-scanner/.tox/readme/bin/python -m twine check 'dist/*' (exited with code 1)

I verified that:

• Python uses the digest_size keyword argument (at least) since version 3.7
• The current and all older (tagged) versions of twine use blake2b(digest_size=…). It doesn’t seem to be an version issue.

Looking at the error message, it’s unclear to me why openssl_blake2b is mentioned (instead of just blake2b):

TypeError: 'digest_size' is an invalid keyword argument for openssl_blake2b()

Does this indicate that there is an incompatible library installed that takes precedence over the C-library that Python is meant to reference? Really just guessing. 🤔

Steps to Reproduce

1. Pull and run the Docker image registry.redhat.io/ubi8/python-39:latest
2. Prepare a tox.ini with the configuration shown above
3. Install tox (pip install tox) and run tox