Git-tracked file is included in build even though setuptools-scm is not installed/configured.

[elongl]

I've read the Data Files Support docs and I'm confused about a behavior I'm seeing. I'm building a Python package using python -m build and my pyproject.toml doesn't specify any build-system or special configuration.

I understand that include-package-data is true by default, but somehow a Git-tracked file that I have in my package is included in the build. According to the docs, this condition should only occur if I've configured a setuptools-scm plugin, which I haven't.

I know it's because of Git because I've copied the package outside of the Git repo and it now excluded those files.

How come this happens even if I don't have setuptools-scm?

[ShreeChaturvedi]

A Git-tracked file can land in the build without any setuptools-scm config. Setuptools itself never talks to Git. walk_revctrl() in setuptools/command/sdist.py only loads the setuptools.file_finders entry-point group, and setuptools registers none.

Installing a plugin is enough. setuptools-scm registers that hook (vcs_versioning._file_finders:find_files) and includes every tracked file as soon as it is importable. You do not need [tool.setuptools_scm]. That is why a copy outside the repo drops the files.

Check the build env:

python -c "from importlib.metadata import entry_points; print([e.value for e in entry_points(group='setuptools.file_finders')])"

python -m build isolates by default, so a host install applies only with --no-isolation. Also delete *.egg-info (especially SOURCES.txt) and MANIFEST before rebuilding. egg_info rereads that cache when no finder is present.

To keep a file out of the wheel after a finder listed it:

[tool.setuptools.exclude-package-data]
"*" = ["unwanted.ext"]

That does not remove it from the sdist. Use exclude or prune in MANIFEST.in for the sdist.