Packaging: license declaration uses outdated format to-be removed Feb. 18, 2026 #19389
Description
CI wheel builder (arbitrary sample, unfold "Building wheel..." section of "pypa/[email protected]" step) reports:
/tmp/build-env-148ua4_i/lib/python3.12/site-packages/setuptools/config/_apply_pyprojecttoml.py:82: SetuptoolsDeprecationWarning: `project.license` as a TOML table is deprecated
!!
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Please use a simple string containing a SPDX expression for `project.license`. You can also use `project.license-files`. (Both options available on setuptools>=77.0.0).
By 2026-Feb-18, you need to update your project and remove deprecated calls
or your builds will no longer be supported.
See https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license for details.
********************************************************************************
!!
corresp(dist, value, root_dir)
/tmp/build-env-148ua4_i/lib/python3.12/site-packages/setuptools/config/_apply_pyprojecttoml.py:61: SetuptoolsDeprecationWarning: License classifiers are deprecated.
!!
********************************************************************************
Please consider removing the following classifiers in favor of a SPDX license expression:
License :: OSI Approved :: MIT License
See https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license for details.
********************************************************************************
!!
dist._finalize_license_expression()
/tmp/build-env-148ua4_i/lib/python3.12/site-packages/setuptools/dist.py:759: SetuptoolsDeprecationWarning: License classifiers are deprecated.
!!
********************************************************************************
Please consider removing the following classifiers in favor of a SPDX license expression:
License :: OSI Approved :: MIT License
See https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license for details.
********************************************************************************
!!
self._finalize_license_expression()
As far as I understand, we are supposed to remove license classifier altogether, and update project.license to be a simple classifier string ("MIT") or add explicit project.license_files (overkill for MIT).
CC @JukkaL as I'm afraid to touch anything license-related myself...