Why are namespace packages used? And where are they used?

To be honest I'm not sure what a namespace package is. We're certainly not intentionally using them but we might be doing so accidentally.

It's a package without a __init__.py. Generally should only be used to combine multiple packages (like adding a.c to a.b from a different place on disk).

And how do you tell that we're using one?

Looks like @ryanking13 added that in #3358. You can try switching it back to packages = find: and see if it breaks. Or we can wait for him to tell us what the reason was.

Yep, tools is missing a __init__.py. Namespace packages weren't created to avoid empty __init__.py's, they were created to allow packages to be split; you get collisions with __init__.py's without namespace packages. There are tradeoffs that have to be made with namespace packages. The better solution here would be to drop an __init__.py in these if you are using importlib.resources to access them. Or to treat them all as data.

Hmm it's not clear to me why we need it. In the tests we add the tools directory to the path, but that should allow us to import modules from the directory. I don't see any instances of import tools or from tools import x or anything.

Thanks @henryiii!

Hopefully we can fix the namespace packages in a followup.

The better solution here would be to drop an init.py in these if you are using importlib.resources to access them.

Sounds good to me. We don't access files in tools directory with importlib, but I always had bad experiences dealing with namespaces packages... so adding an empty __init__.py then use packages = find: might be better.

If we don't import from it isn't the correct thing to indicate that everything in the directory is data files?

If we don't import from it isn't the correct thing to indicate that everything in the directory is data files?

That would be ideal, but I never made Subdirectory for data files + packages = find: combination successful. Probably someone who know setuptools better than me could try.