Currently we use pkg_resources-style namespace packages. Using pkg_resources is deprecated (see https://setuptools.pypa.io/en/latest/pkg_resources.html), it seems not yet clear when it is removed from setuptools.

The current future are PEP 420: Implicit namespace packages.

This requires:

• all the packages sharing a namespace to switch over to PEP 420.
• removing the __init__.py files existing to create a namespace
• removing namespace_packages declaration from setup.py
• maybe removal of the dependency on setuptools? (Maybe we could even switch to pyproject.toml.)

zopefoundation hosts the following namespaces:

• zope, zope.app (zope, zope.app – 117 repos #331) - 117 repos
• Products – 22 repos (Switch Products packages to PEP 420 - 22 repos #363)
• zc (zc, zc.recipe – 10 repos #346)
• keas (probably only some packages of that namespace) – all repos archived
• refline (probably only some packages of that namespace) - all repos archived
• grokui – all repos archived
• hurry – 1 repos (Switch to PEP 420 native namespace. hurry.query#18)
• cipher – all repos archived
• five – 4 repos – migrated
• megrok: 1 repos (Switch to implicit (PEP 420) namespace. megrok.strictrequire#8)

See the discussion in pypa/setuptools#3434 for some more details.

Suggestion:

• ✅ Try out on a small namespace where probably all packages are hosted by zopefoundation (grokcore?, z3c?, zope.app?)
• If this works fine (especially in zc.buildout), adapt the other namespaces.
  • This will require coordination with the Plone folks.
  • This would also require a big warning sign that other packages hosted outside zopefoundation but using the same namespaces also have to switch to PEP 420.

Cc-ing: @dataflake @mauritsvanrees @gforcada @mgedmin @jensens

See also https://packaging.python.org/en/latest/guides/packaging-namespace-packages/