Add private function calls check to make sure there isn't one being called outside of the module it was defined

[Eric-Mendes]

I have drafted a pre-commit hook to make sure there isn't a private function being called outside of the module it was defined. Would it make sense as an optional linting rule? If so I'd be happy to contribute with code.

[charliermarsh]

Is this similar to private-member-access?

[Eric-Mendes]

Perhaps it could be an extension to that rule, @charliermarsh. My code doesn't check for class private member access. It checks for module private member access. Here's an example of something that should raise an exception:

# a.py
def _foo(*args, **kwargs):
    return "Hello World"

# b.py
import a

print(a._foo())  # Raises an exception

# c.py
from a import _foo

print(_foo())  # Also raises an exception

Have I misunderstood the rule you've mentioned, or am I really onto something here?

[charliermarsh]

I believe this would be closed by #5920.

[Eric-Mendes]

Indeed, @charliermarsh. Thanks for pointing that out, I didn't see that issue before.