Custom option (--some_path) fails when path exists

[adentinger]

• a detailed description of the bug or problem you are having

When adding a custom option via pytest_addoption, passing a path that doesn't exist has it passed correctly, but when the path does exist, pytest fails. I'd have expected both to work. Seems like such a basic issue I really feel like I'm missing something obvious...

$ pytest -rP --some_path /usr/bin/nonexistent
# output "some_path: /usr/bin/nonexistent"

$pytest -rP --some_path /usr
# ERROR: usage: pytest [options] [file_or_dir] [file_or_dir] [...]
# pytest: error: unrecognized arguments: --some_path
#   inifile: None
#   rootdir: /usr/bin

• output of pip list from the virtual environment you are using

Package Version

---

iniconfig 2.1.0
packaging 25.0
pip 24.0
pluggy 1.5.0
pytest 8.3.5

• pytest and operating system versions

Ubuntu, also Win11

• minimal example if possible

mkdir foo
cd foo
python3 -m venv .venv
.venv/bin/python3 -m pip install pytest
mkdir tests

# tests/conftest.py
import pytest

def pytest_addoption(parser: pytest.Parser):
    parser.addoption(
        "--some_path",
        action="store",
        help="Path to something.",
        type=str,
    )

@pytest.fixture
def some_path(request) -> str:
    path_raw: str = request.config.getoption("--some_path")
    return path_raw

# tests/test_foo.py
def test_foo(some_path):
    print(f"some_path: {some_path}")

Then we are ready. Non-existent path:

$ .venv/bin/pytest -rP --some_path /usr/bin/hola
====================== test session starts ======================
platform linux -- Python 3.12.3, pytest-8.3.5, pluggy-1.5.0
rootdir: /home/me/foo
collected 1 item

tests/test_foo.py .                                       [100%]

============================ PASSES =============================
___________________________ test_foo ____________________________
--------------------- Captured stdout call ----------------------
some_path: /usr/bin/hola
======================= 1 passed in 0.00s =======================

Path that exists:

$ .venv/bin/pytest -rP --some_path /usr/bin
ERROR: usage: pytest [options] [file_or_dir] [file_or_dir] [...]
pytest: error: unrecognized arguments: --some_path
  inifile: None
  rootdir: /usr/bin