fix: definitive PyPI metadata fix - license_files in [metadata] + pyproject.toml build-system only

Root cause: license_files= was in [options] section of setup.cfg (silently ignored).
Must be in [metadata] section where ConfigMetadataHandler reads it.

pyproject.toml with [build-system] only (no [project]) is safe alongside setup.py -
this is the standard pattern used by lxml, numpy, etc.

packaging>=24.2 in twine install handles License-File field correctly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ratal

.github/workflows/release-linux.yml

@@ -23,8 +23,6 @@ jobs:
           CIBW_BUILD: "cp39-* cp310-* cp311-* cp312-* cp313-*"
           CIBW_MANYLINUX_X86_64_IMAGE: manylinux2014
           CIBW_MANYLINUX_AARCH64_IMAGE: manylinux2014
-          CIBW_BEFORE_BUILD: pip install setuptools numpy cython
-          CIBW_BUILD_FRONTEND: "pip; args: --no-build-isolation"
           CIBW_TEST_COMMAND: python -c "import mdfreader"
       - uses: actions/upload-artifact@v4
         with:
@@ -45,5 +43,5 @@ jobs:
           TWINE_USERNAME: __token__
           TWINE_PASSWORD: ${{ secrets.PYPI_TOKEN }}
         run: |
-          pip install twine
+          pip install twine "packaging>=24.2"
           twine upload dist/* --skip-existing

.github/workflows/release-macos.yml

@@ -14,8 +14,6 @@ jobs:
         env:
           CIBW_BUILD: "cp39-* cp310-* cp311-* cp312-* cp313-*"
           CIBW_ARCHS: x86_64 arm64
-          CIBW_BEFORE_BUILD: pip install setuptools numpy cython
-          CIBW_BUILD_FRONTEND: "pip; args: --no-build-isolation"
           CIBW_TEST_COMMAND: python -c "import mdfreader"
       - uses: actions/upload-artifact@v4
         with:
@@ -35,5 +33,5 @@ jobs:
           TWINE_USERNAME: __token__
           TWINE_PASSWORD: ${{ secrets.PYPI_TOKEN }}
         run: |
-          pip install twine
+          pip install twine "packaging>=24.2"
           twine upload dist/* --skip-existing

.github/workflows/release-windows.yml

@@ -13,8 +13,6 @@ jobs:
         uses: pypa/cibuildwheel@v2.22
         env:
           CIBW_BUILD: "cp39-win_amd64 cp310-win_amd64 cp311-win_amd64 cp312-win_amd64 cp313-win_amd64"
-          CIBW_BEFORE_BUILD: pip install setuptools numpy cython
-          CIBW_BUILD_FRONTEND: "pip; args: --no-build-isolation"
           CIBW_TEST_COMMAND: python -c "import mdfreader"
       - uses: actions/upload-artifact@v4
         with:
@@ -34,5 +32,5 @@ jobs:
           TWINE_USERNAME: __token__
           TWINE_PASSWORD: ${{ secrets.PYPI_TOKEN }}
         run: |
-          pip install twine
+          pip install twine "packaging>=24.2"
           twine upload dist/* --skip-existing

pyproject.toml

@@ -0,0 +1,3 @@
+[build-system]
+requires = ["setuptools>=68", "Cython>=3.0", "numpy>=1.14"]
+build-backend = "setuptools.build_meta"

setup.cfg

@@ -1,10 +1,11 @@
-[bdist_wheel]
-universal=1
+[metadata]
+license_files =
+
 [build_ext]
 inplace=1
+
 [options]
 setup_requires = cython
-license_files =
 
 [tool:pytest]
 testpaths = mdfreader/tests
@@ -14,4 +15,4 @@ markers =
     compare_mdfr: cross-validates mdfreader vs mdfr Rust library (run with -m compare_mdfr)
 tmp_path_retention_count = 1
 tmp_path_retention_policy = failed
-tmp_path_base_dir = /home/ratal/workspace/mdfreader/.pytest_tmp
+tmp_path_base_dir = /home/ratal/workspace/mdfreader/.pytest_tmp