已安装 Python 包，但 __init__ 中的内容不可导入

Question

I have the following package structure:

module_installer/   
|-- module_installer
|   `-- __init__.py 
`-- setup.py        

setup.py

from setuptools import setup                             
setup(name='module_installer')

module_installer/__init__.py

class ImportMe():
    pass         

Being in the "root directory" of the package the class ImportMe is importable:

module_installer$ tree --charset=ASCI
|-- module_installer
|   `-- __init__.py
`-- setup.py
python -c "from module_installer import ImportMe"
# This makes sense. The current dir is in python path and the `module_installer` has `__init__.py.

However if I install it and try to run it from a different directory it fails:

module_installer$ pip install .
module_installer$ cd /some_other_dir
some_other_dir$ python -c "from module_installer import ImportMe"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ImportError: cannot import name 'ImportMe' from 'module_installer' (unknown location)

Grepping pip freeze for module-installer shows the packages successfully installed.

Exploring the package for files doesn't show the package installed:

$ pip show -f module-installer
...
Location: /home/user/Envs/se_ena/lib/python3.7/site-packages
...
Files:
  module_installer-0.0.0.dist-info/INSTALLER
  module_installer-0.0.0.dist-info/METADATA
  module_installer-0.0.0.dist-info/RECORD
  module_installer-0.0.0.dist-info/WHEEL
  module_installer-0.0.0.dist-info/top_level.txt
# No traces of module_installer/__init__.py?

Doesn't the __init__.py get installed correctly and the class isn't importable?

Answer 1

Looks to me like the setuptools.setup function call in setup.py is missing the list of packages as an argument to the packages parameter.

setup.py :

setup(
    # ...
    packages=['module_installer'],
    # ...
)

To avoid listing packages manually, setuptools provides the following utility functions:

• find_packages
• find_namespace_packages