Regression for #1186

[cdce8p]

#1186 added logic for parsing package names. This seems to have caused a regression visible as too-many-function-args error in the example below.

File structure

b
├── __init__.py
├── a.py
└── level1
    ├── __init__.py
    └── b.py

# b/a.py

# pylint: disable=missing-docstring

from .level1.b import func

def do_something(var, some_other_var):  # error
    func(var, some_other_var)

# b/level1/__init__.py

def func(var):
    pass

# b/level1/b.py

def func(var, some_other_var):
    pass

Runing pylint: pylint -sn b/a.py

************* Module b.a
b/a.py:8:4: E1121: Too many positional arguments for function call (too-many-function-args)

The error seems to happen as func is wrongly inferred as coming from b/level1/__init__.py, thus having one argument less than passed. The inference happens here: typecheck.py -> visit_call.

--
@DanielNoord As you authored #1186, would you mind taking a look at this?

[DanielNoord]

I can take a look although I can't promise a timeframe. I am quite busy this week.

[cdce8p]

Tested a few more things. Reverting the change to the return would fix the issue.
https://github.com/PyCQA/astroid/pull/1186/files#diff-4be1f47d39f9b6a7ff09c297908537522c8b33a348c0754d429a47dfa3308385L747-R755

-          return f"{package_name}.{modname}"
+          return f"{package_name}.{modname.split('.')[0]}"

Not sure that was even necessary as all the test cases seem to pass even without it. If it is, maybe there needs to be a conditional added?