Dependency with dashed distribution-name is marked as unused if there is a folder with its import name in the repository

[LordFckHelmchen]

Describe the bug
When a package with a dashed distribution name (e.g. nats-py) is used in a repository that contains a subpackage with the same name as the import name (e.g. nats), fawltydeps reports the dependency as unused although it is used.

To Reproduce

1. Create a repository with the following structure:

   pyproject.toml  # Project config
   src             # Source folder
    |-- main.py    # Contains the import
    |-- nats       # Empty folder
   

2. Add the following minimal content to pyproject.toml:

   [project]
   name = "test"
   version = "0.1.0"
   requires-python = ">=3.13.2"
   dependencies = ["nats-py"

3. Add the following content to the main.py:

   import nats
   print(f"{nats=}")

4. Initialize a local .venv & verify that the program is working and it correctly imports the package:

   > python src/main.py
   nats=<module 'nats' from '.../test/.venv/Lib/site-packages/nats/__init__.py'>

5. Run fawltydeps on the project

Expected behavior

No undeclared or unused dependencies detected.

Observed behavior

These dependencies appear to be unused (i.e. not imported):
- 'nats-py'

For a more verbose report re-run with the `--detailed` option.

Environment

• Windows 11
• FawltyDeps v0.20.0

Additional context

Also tested with other packages, nats is only an example