解决“ModuleNotFoundError: ...'__main__' is not a package”错误

Question

I've got a project running on a server with the structure

proj
    __init__.py
    module_a.py
    module_b.py
    main.py

And in the header of main.py, I import from other modules with the format

from .module_a import func1
from .module_b import func2

This runs fine on the server, but when I'm testing things on my local machine it raises the error:

ModuleNotFoundError: No module named '__main__.module_a'; '__main__' is not a package

There have been a lot of questions asked regarding this error and the accepted solution is almost always to replace the import statement with

from proj.module_a import func1

Is there something I can do to configure my local environment to allow this type of syntax without having a completely different set of import statements depending on whether the code is running locally or remotely?

Answer 1

Keep your imports relative, without using the package full path, so that you have the flexibility of renaming it as you wish, like in

from .module_a import func1

Then in your local environment, change your current dir to the proj parent folder and run:

python -m proj.main

An alternative would be to rename main.py to __main__.py and then just writing

python -m proj

will do. But that may affect the behaviour on the server if you copy the files as is.

Packages are usually to be imported. This is a common problem when we start running from arbitrary scripts located inside the package (in this case main.py ). If the package is simply imported from outside, everything works.