setuptools warning about missing packages

[mauritsvanrees]

During release I get:

/Users/maurits/community/plone-coredev/6.0/lib/python3.11/site-packages/setuptools/command/build_py.py:207: _Warning: Package 'plone.app.event.browser.resources' is absent from the `packages` configuration.
!!

********************************************************************************
############################
# Package would be ignored #
############################
Python recognizes 'plone.app.event.browser.resources' as an importable package[^1],
but it is absent from setuptools' `packages` configuration.

This leads to an ambiguous overall configuration. If you want to distribute this
package, please make sure that 'plone.app.event.browser.resources' is explicitly added
to the `packages` configuration field.

Alternatively, you can also rely on setuptools' discovery methods
(for example by using `find_namespace_packages(...)`/`find_namespace:`
instead of `find_packages(...)`/`find:`).

You can read more about "package discovery" on setuptools documentation page:

- https://setuptools.pypa.io/en/latest/userguide/package_discovery.html

If you don't want 'plone.app.event.browser.resources' to be distributed and are
already explicitly excluding 'plone.app.event.browser.resources' via
`find_namespace_packages(...)/find_namespace` or `find_packages(...)/find`,
you can try to use `exclude_package_data`, or `include-package-data=False` in
combination with a more fine grained `package-data` configuration.

You can read more about "package data files" on setuptools documentation page:

- https://setuptools.pypa.io/en/latest/userguide/datafiles.html


[^1]: For Python, any directory (with suitable naming) can be imported,
even if it does not contain any `.py` files.
On the other hand, currently there is no concept of package data
directory, all directories are treated like packages.
********************************************************************************

!!
check.warn(importable)

This is for several directories:

• plone.app.event.browser.resources
• plone.app.event.profiles.default
• plone.app.event.profiles.default.types
• plone.app.event.profiles.testing
• plone.app.event.profiles.testing.types
• plone.app.event.tests.javascripts
• plone.app.event.tests.qunit
• plone.app.event.tests.robot

If you have the build package in a Python venv, you can see this also when doing bin/python -m build .

In setup.py we are already using setuptools.find_packages, which I expect we do in most Plone packages (and they likely have the same problem). Trying it out in a prompt:

$ python
>>> import setuptools
>>> setuptools.find_packages()
['plone', 'plone.app', 'plone.app.event', 'plone.app.event.portlets', 'plone.app.event.ical', 'plone.app.event.tests', 'plone.app.event.browser', 'plone.app.event.dx', 'plone.app.event.upgrades']
>>> setuptools.find_namespace_packages()
['dist', 'docs', 'news', 'plone', 'docs.api', 'docs.api.ical', 'docs.api.browser', 'docs.api.dx', 'plone.app', 'plone.app.event', 'plone.app.event.portlets', 'plone.app.event.ical', 'plone.app.event.tests', 'plone.app.event.browser', 'plone.app.event.dx', 'plone.app.event.upgrades', 'plone.app.event.profiles', 'plone.app.event.tests.robot', 'plone.app.event.tests.javascripts', 'plone.app.event.tests.qunit', 'plone.app.event.browser.resources', 'plone.app.event.profiles.default', 'plone.app.event.profiles.testing', 'plone.app.event.profiles.default.types', 'plone.app.event.profiles.testing.types']

If everything would be in src, we could simply do setuptools.find_namespace_packages("src") and then it seems to find exactly the packages we want. Maybe we should do this sooner for all packages, separate from moving to native namespace packages. A src-layout seems the recommended approach these days anyway.