How do native namespaces work?

[Thomas Nyberg]

Hello,

I'm trying to understand native namespaces. I'm currently using python
3.5 as packaged in debian 9. I've been following the instructions here:

	https://packaging.python.org/guides/packaging-namespace-packages/#native-namespace-packages

Those instructions link to the following example:

	https://github.com/pypa/sample-namespace-packages/tree/master/native

I presume I'm doing something silly, but I can't get that to work. I've
tried creating a virtual environment as:

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$ python3 -m venv venv
$ source venv/bin/activate
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And then I've gone into those repo folders and run their setup.py files
(e.g. for namespace a):

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$ cd sample-namespace-packages/native/pkg_a/
$ python3 setup.py install
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Then if I try to run their sample verification file, things fail:

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$ cat sample-namespace-packages/verify_packages.py
from example_pkg import a
from example_pkg import b

print(a.name)
print(a.__path__)
print(b.name)
print(b.__path__)
$ python3 sample-namespace-packages/verify_packages.py
Traceback (most recent call last):
  File "sample-namespace-packages/verify_packages.py", line 1, in <module>
    from example_pkg import a
ImportError: No module named 'example_pkg'
--------------------------------------------------

Things seem to be installing:

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$ ls venv/lib/python3.5/site-packages/
easy-install.pth           pkg_resources
easy_install.py            pkg_resources-0.0.0.dist-info
example_pkg_a-1-py3.5.egg  __pycache__
example_pkg_b-1-py3.5.egg  setuptools
pip                        setuptools-32.3.1.dist-info
pip-9.0.1.dist-info
--------------------------------------------------

Am I missing something totally obvious here? Does anyone here see what
I'm doing wrong? Thanks for any help!

Cheers,
Thomas