Linting fails if module contains module of the same name

[iFreilicht]

Steps to reproduce

Given multiple files:

.
`-- a/
    |-- a.py
    `-- b.py

Which are all empty, running pylint a fails:

$ pylint a
************* Module a
a/__init__.py:1:0: F0010: error while code parsing: Unable to load file a/__init__.py:
[Errno 2] No such file or directory: 'a/__init__.py' (parse-error)
$

However, if I rename a.py, pylint a succeeds:

$ mv a/a.py a/c.py
$ pylint a
$

Alternatively, I can also touch a/__init__.py, but that shouldn't be necessary anymore.

Current behavior

Running pylint a if a/a.py is present fails while searching for an __init__.py file.

Expected behavior

Running pylint a if a/a.py is present should succeed.

pylint --version output

Result of pylint --version output:

pylint 3.0.0a3
astroid 2.5.6
Python 3.8.5 (default, Jan 27 2021, 15:41:15) 
[GCC 9.3.0]

Additional info

This also has some side-effects in module resolution. For example, if I create another file r.py:

.
|-- a
|   |-- a.py
|   `-- b.py
`-- r.py

With the content:

from a import b

Running pylint -E r will run fine, but pylint -E r a will fail. Not just for module a, but for module r as well.

************* Module r
r.py:1:0: E0611: No name 'b' in module 'a' (no-name-in-module)
************* Module a
a/__init__.py:1:0: F0010: error while code parsing: Unable to load file a/__init__.py:
[Errno 2] No such file or directory: 'a/__init__.py' (parse-error)

Again, if I rename a.py to c.py, pylint -E r a will work perfectly.

[hippo91]

@iFreilicht thanks for your report.

[jacobtylerwalls]

#4909 was a duplicate.

[jacobtylerwalls]

#7114 was not correct and will be reverted in #7304.

Regression test for test_lint.py for anyone attempting a fix:

def test_identically_named_nested_module(initialized_linter: PyLinter) -> None:
    with tempdir():
        create_files(["identical/identical.py"])
        with open("identical/identical.py", "w", encoding="utf-8") as f:
            f.write("import imp")
        initialized_linter.check(["identical"])
    assert initialized_linter.stats.by_msg["deprecated-module"] == 1