Context

In PYTHON-5970 we had been surprised by a change to TestPyPI that prevented the download of artifacts older than 14 days. This affected our nightly uploads, which we marked with skip-existing but failed with a 400 error. The problem has since been addressed on TestPyPI.

Based on a Python Discuss thread, the PyPI admins are in the process of deprecating TestPyPI and have already de-prioritized it.

We should do local checks that we know will work, which have already been done for PyMongo in PYTHON-5970, validate-pyproject and twine check --strict:

$ uv tool install  'validate-pyproject[all]'
$ validate-pyproject pyproject.toml
Valid file: pyproject.toml
$ uv tool run --from build pyproject-build .
$ uv tool run twine check --strict dist/*.*
Installed 22 packages in 18ms
Checking dist/pymongo-4.18.0.dev0-cp313-cp313-macosx_26_0_arm64.whl: PASSED
Checking dist/pymongo-4.18.0.dev0.tar.gz: PASSED

Definition of done

Complete the above migration for nightly and full release workflows across the repos using the task tracking sheet.

Pitfalls

None