--fail-on-flaky not compatible with mark usage

[ricardo-passthrough]

--fail-on-flaky only exits with code 7 if --reruns is passed via CLI. Otherwise it breaks the execution regardless of flakiness.

Also the implementation implies if I add --reruns i want this to always return exit status 7... this was not what I was expecting.

test_flaky.py:

@pytest.mark.flaky(reruns=10)
def test_flaky_test():
    assert True

$ pytest -k test_flaky_test --fail-on-flaky
...
File "$HOME/.local/share/virtualenvs/<venv>/lib/python3.9/site-packages/pytest_rerunfailures.py", line 632, in pytest_sessionfinish
    if session.config.getvalue("reruns") > 0:
TypeError: '>' not supported between instances of 'NoneType' and 'int'

[ricardo-passthrough]

maybe something like this would work best:

@pytest.hookimpl(trylast=True)
def pytest_sessionfinish(session: pytest.Session, exitstatus: int) -> None:
    if exitstatus != 0:
        return

    for item in session.items:
        if hasattr(item, "execution_count"):
            if item.execution_count > 1:
                session.exitstatus = 7
                break

[icemac]

Thank you for writing up the issue. A pull request would be welcome.

[ricardo-passthrough]

pushed a PR :)