pip install -e doesn't allow to import via package dir

Solution 1:

In order to use a so-called src-layout with setuptools the setup.py should look like this :

from setuptools import setup, find_packages

setup(
    name='test-pkg',
    packages=find_packages('src'),
    package_dir={
        '': 'src',
    },
)

The package_dir should get an empty string as key.

It is kind of explained in the "deprecated" documentation of setuptools:

The keys to this dictionary are package names, and an empty package name stands for the root package. The values are directory names relative to your distribution root. In this case, when you say packages = ['foo'], you are promising that the file lib/foo/__init__.py exists.

-- https://setuptools.pypa.io/en/latest/deprecated/distutils/setupscript.html?highlight=package_dir#listing-whole-packages

...and kind of in the newest version of the documentation, but it is somewhat possible to piece things together:

• https://setuptools.pypa.io/en/latest/userguide/package_discovery.html#using-find-or-find-packages
• https://setuptools.pypa.io/en/latest/userguide/declarative_config.html#using-a-src-layout