I would expect that session fixtures are run once per session - but it seems if a flaky test reruns, it will run session scoped fixtures' teardown code, and then their setup again.

This can result in costly setup/teardown being unnecessarily rerun, and also seems to go against the whole point of labelling the fixture session

Reproduction:

@pytest.fixture(scope="session")
def example_fixture():
    print("\nSetup")
    yield
    print("Teardown")

@pytest.mark.flaky(reruns=1)
def test_example_fixture(example_fixture):
    assert 0

Running with pytest -s -v ... I get:

plugins: timeout-1.2.0, rerunfailures-2.2, repeat-0.4.1, ordering-0.5
collected 1 items 

scripts/autotest/tests/conftest.py::test_example_fixture 
Setup
Teardown
RERUN
scripts/autotest/tests/conftest.py::test_example_fixture 
Setup
Teardown
FAILED