Trouble with minimal example Python Module Imports

Question

I've made a minimal example project to attempt to resolve my module imports issue. The structure is as follows:

MyProject/
├── main.py
└── utils/
    ├── __init__.py
    ├── foo.py
    └── bar.py

main.py only contains this code: from utils import foo

__init__.py does not contain any code

foo.py only contains this code: from bar import Bar

bar.py only contains this code: class Bar: pass

If I run python utils/bar.py, it runs with no exceptions.

Similarly, if I run python utils/foo.py, it runs with no exceptions.

However, if I run python main.py, it results in the following exception: ModuleNotFoundError: No module named 'bar'

Is there any way to resolve this issue? Or is it even an issue, perhaps I'm doing something I'm not supposed to?

That fixed the ability to run main.py, but if I try to run foo.py, I get a new error: "ImportError: attempted relative import with no known parent package" — Nevermore, Sep 19 '21 at 21:20
``` try: from .bar import Bar except ImportError: # python3 from bar import Bar except ValueError: # python2 from bar import Bar ``` — jmbarbier, Sep 19 '21 at 21:21
That worked! Thanks! Interesting though... is that standard practice for this sort of thing? — Nevermore, Sep 19 '21 at 21:25
Calling "subpackage" and "mainpackage" is not really a standard practice, neither. There may be other maybe cleaner ways avoiding these except, by tweaking python modules search path in main.py for example : https://stackoverflow.com/questions/16981921/relative-imports-in-python-3?rq=1 — jmbarbier, Sep 19 '21 at 21:30
Thanks for the link, lots to unpack there. I've always called my submodules for unit testing purposes, for example in foo.py I might have an ```if __name__ == "__main__": run_tests()``` but it seems like this behavior may not be the "correct" or "intended" way of doings things after all. — Nevermore, Sep 19 '21 at 21:38

score 1 · Accepted Answer · answered Sep 19 '21 at 21:26

If you want to use it as a standalone call (python utils/foo.py) and from main (python main.py), you can use both imports :

try:
    from .bar import Bar
except ImportError: # for python3
    from bar import Bar
except ValueError: # for python2
    from bar import Bar

1 Answers1