fix: exclude setuptools.tests from wheel distribution

[Bahtya]

Problem

Starting from some release between v69.0.2 and v81.0.0, setuptools includes its own test suite in the wheel distribution. This violates the packaging guide:

Wheels are meant to contain exactly what is to be installed

Root Cause

The exclude patterns in pyproject.toml:

exclude = [
    "*.tests",
    "*.tests.*",
]

These glob patterns match packages named like foo.tests but do not match setuptools/tests/ because that is a subpackage of setuptools, not a top-level package matching the *.tests pattern.

Solution

Add explicit entries for the actual test package:

exclude = [
    "*.tests",
    "*.tests.*",
    "setuptools.tests",
    "setuptools.tests.*",
]

Fixes #5212

[abravalheri]

Hi @Bahtya, thank you very much for the contribution.

I believe that this change is not working as expected: the original glob pattern itself should be working fine, but there is a different problem that influences the behaviour (a complicated one, nevertheless, because half of the community wants it to behave in a way while the other half wants it to behave in a different way: #3260, #3340)

But, just for the sake of sanity checking, could you please add some tests that assert that the proposed changes work to achieve the expected results?

[Bahtya]

Thanks for the feedback! I see the linked issues about the glob exclude pattern complexities.

Looking at this more carefully: if *.tests and *.tests.* should already match setuptools/tests, then the problem might be elsewhere in how setuptools.packages.find processes the exclude patterns during wheel building.

I'll investigate the actual wheel contents to understand what's happening. Could you point me to where in the build pipeline the exclude patterns are applied? Is the issue perhaps that setuptools/tests is being included because it's not matching the *.tests glob as a sub-package path?