The dependency license checker only read the legacy free-text
`info.license` field from PyPI. Packages that adopt PEP 639 publish
their license as an SPDX expression in `info.license_expression` and
leave the legacy field null, so the checker reported "Unknown license"
and failed CI for every newly-bumped PEP 639 dependency.
`get_package_license_from_pypi` now resolves the license in order:
`license_expression`, then legacy `license`, then the
`License :: OSI Approved :: ...` trove classifiers.
`is_license_acceptable` splits compound SPDX expressions on the
uppercase OR/AND operators (case-sensitive, so the lowercase
`-or-later` inside an identifier is not mistaken for an operator) and
strips `WITH <exception>` suffixes, requiring every component to be
acceptable. Free-text license blobs are detected and fall back to the
original whole-string matching.
The `black` and `pydantic-settings` entries in liccheck.ini that
existed solely to work around this now resolve correctly on their own
and have been removed.
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