Possible false positive cyclical import

[Gjgarr]

Describe the bug
Pyright reports a cyclic import within __init__.py when a star-import includes an imported module at the same level.

To Reproduce
Reported as cyclical import:

# ./cyclical/__init__.py
from .f1 import * # Cycle detected - __init__.py & f1.py

# ./cyclical/f1.py
from . import f2

# ./cyclical/f2.py (empty)

No cyclical import reported:

# ./not_cyc/__init__.py (empty)

# ./not_cyc/f1.py
from .f2 import *

# ./not_cyc/f2.py
from . import f3

# ./not_cyc/f3.py (empty)

Expected behavior
Neither scenario reported as cyclical.

VS Code extension or command-line
VS Code extension - pylance v2022.3.4

[erictraut]

This is intended behavior, not a false positive.

The statement from .f1 import * within an __init__.py method imports f1 and assigns a reference to the f1 module to the local symbol f1. The f1 module imports f2 from the __init__.py module. So this is an actual cyclical import.

The cycle detection code in pyright is admittedly strict about what constitutes an import cycle. It will detect cycles that do not necessarily result in runtime exceptions. That's intended. If you want to use this diagnostic check, you'll need to factor your code to avoid all cycles.