DeprecationWarning: Implicit None on return values is deprecated and will raise KeyErrors.

[domdfcoding]

Your Environment

Thank you for taking the time to report an issue.

To more efficiently resolve this issue, we'd like to know some basic information about your system and setup.

1. Your operating system:

Ubuntu 20.04

2. Version of python you are running:

Python 3.8.10

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

pip (via tox)

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

twine --version

twine version 4.0.2 (importlib-metadata: 6.0.0, keyring: 23.13.1, pkginfo: 1.9.6, requests: 2.28.2, requests-toolbelt: 0.10.1, urllib3: 1.26.14)

5. Which package repository are you targeting?

PyPI

The Issue

Please describe the issue that you are experiencing.

Running twine emits a deprecation warning:

python3 -Walways -m twine --version
venv/lib/python3.8/site-packages/twine/__init__.py:43: DeprecationWarning: Implicit None on return values is deprecated and will raise KeyErrors.
  __license__ = metadata["license"]
twine version 4.0.2 (importlib-metadata: 6.0.0, keyring: 23.13.1, pkginfo: 1.9.6, requests: 2.28.2, requests-toolbelt: 0.10.1, urllib3: 1.26.14)

It appears that twine's metadata does not include the License key. As a result, the metadata "dictionary" twine is getting from importlib_metadata doesn't contain a key license.

The metadata in the wheel uploaded to PyPI can be seen here: https://www.wheelodex.org/projects/twine/#metadata

Steps to Reproduce

If the issue is predictable and consistently reproducible, please list the steps here.

• Run python3 -Walways -m twine --version

[bhrutledge]

Thanks for the report. This was fixed in #968, and will be included in the next Twine release.

[jaraco]

Today I tried to release importlib_metadata 8.0.0, which removes the compatible behavior and begins raising KeyErrors for missing keys. When I did, the release failed with this error:

Successfully built importlib_metadata-8.0.0.tar.gz and importlib_metadata-8.0.0-py3-none-any.whl
release: commands[2]> python -m twine upload 'dist/*'
Traceback (most recent call last):
  File "<frozen runpy>", line 189, in _run_module_as_main
  File "<frozen runpy>", line 148, in _get_module_details
  File "<frozen runpy>", line 112, in _get_module_details
  File "/home/runner/work/importlib_metadata/importlib_metadata/.tox/release/lib/python3.12/site-packages/twine/__init__.py", line 40, in <module>
    __uri__ = metadata["home-page"]
              ~~~~~~~~^^^^^^^^^^^^^
  File "/home/runner/work/importlib_metadata/importlib_metadata/importlib_metadata/_adapters.py", line 54, in __getitem__
    raise KeyError(item)
KeyError: 'home-page'
release: exit 1 (0.08 seconds) /home/runner/work/importlib_metadata/importlib_metadata> python -m twine upload 'dist/*' pid=1994
  release: FAIL code 1 (18.00=setup[12.88]+cmd[0.03,5.01,0.08] seconds)
  evaluation failed :( (18.21 seconds)

It looks like twine is still reliant on the deprecated behavior.

I'm unsure if we should re-open this issue or start a new one, since the concerns are very closely related.

[jaraco]

When running the current test suite, I see that the DeprecationWarnings were apparent:

 twine main @ .tox/py/bin/pytest --collect-only -qq
tests/test_auth.py: 19
tests/test_check.py: 13
tests/test_cli.py: 2
tests/test_commands.py: 5
tests/test_main.py: 3
tests/test_package.py: 32
tests/test_register.py: 6
tests/test_repository.py: 25
tests/test_settings.py: 16
tests/test_upload.py: 36
tests/test_utils.py: 35
tests/test_wheel.py: 10

================================================================ warnings summary ================================================================
twine/__init__.py:40
  /Users/jaraco/code/pypa/twine/twine/__init__.py:40: DeprecationWarning: Implicit None on return values is deprecated and will raise KeyErrors.
    __uri__ = metadata["home-page"]

twine/__init__.py:42
  /Users/jaraco/code/pypa/twine/twine/__init__.py:42: DeprecationWarning: Implicit None on return values is deprecated and will raise KeyErrors.
    __author__ = metadata["author"]

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html

[qqiao2024]

same error got from gitlab-ci.
The same code is working fine on my laptop.

twine 5.1.0

$ python -m twine check dist/*
Traceback (most recent call last):
  File "/py/lib/python3.8/runpy.py", line 185, in _run_module_as_main
    mod_name, mod_spec, code = _get_module_details(mod_name, _Error)
  File "/py/lib/python3.8/runpy.py", line 144, in _get_module_details
    return _get_module_details(pkg_main_name, error)
  File "/py/lib/python3.8/runpy.py", line 111, in _get_module_details
    __import__(pkg_name)
  File "/venv/lib/python3.8/site-packages/twine/__init__.py", line 40, in <module>
    __uri__ = metadata["home-page"]
  File "/venv/lib/python3.8/site-packages/importlib_metadata/_adapters.py", line 54, in __getitem__
    raise KeyError(item)
KeyError: 'home-page'

[RenaudLN]

I had a build succeed 3h ago with twine 5.1.0 then fail 5mn ago with that same version.

Working

Not working

[yym68686]

This command fixed the issue.

pip install importlib_metadata==7.2.1

Add this line to github action

name: Publish Python 🐍 distributions 📦 to PyPI

on:
  push:
    tags:
      - '*'
    branches:
      - main

jobs:
  build-n-publish:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    - name: Set up Python
      uses: actions/setup-python@v2
      with:
        python-version: '3.x'
    - name: Install dependencies
      run: |
        python -m pip install --upgrade pip
        pip install setuptools wheel twine
+      pip install importlib_metadata==7.2.1
    - name: Build and publish
      env:
        TWINE_USERNAME: __token__
        TWINE_PASSWORD: ${{ secrets.PYPI_API_TOKEN }}
      run: |
        python setup.py sdist bdist_wheel
        twine upload dist/*

[qqiao2024]

This command fixed the issue.

pip install importlib_metadata==7.2.1

yes, the bug happens with importlib_metadata 8.0.0

[Erotemic]

Ah, release season is so fun!

The amount of hair I've pulled out where something that was working an hour ago is no longer working... Glad to know the issue is being tracked!

[henryiii]

5.1.0 reverted the (fixed) reliance on this behavior.

[JohnVillalovos]

FYI: A PR to fix this KeyError issue is at #1115

[JohnVillalovos]

The twine issue was resolved in 5.1.1 and is published on PyPI: https://pypi.org/project/twine/