Always use getfixturemarker() to access _pytestfixturefunction

Keep knowledge of how the marker is stored encapsulated in one place.

src/_pytest/nose.py

@@ -2,11 +2,12 @@
 from _pytest import python
 from _pytest import unittest
 from _pytest.config import hookimpl
+from _pytest.fixtures import getfixturemarker
 from _pytest.nodes import Item
 
 
 @hookimpl(trylast=True)
-def pytest_runtest_setup(item):
+def pytest_runtest_setup(item) -> None:
     if is_potential_nosetest(item):
         if not call_optional(item.obj, "setup"):
             # Call module level setup if there is no object level one.
@@ -15,7 +16,7 @@ def pytest_runtest_setup(item):
         item.session._setupstate.addfinalizer((lambda: teardown_nose(item)), item)
 
 
-def teardown_nose(item):
+def teardown_nose(item) -> None:
     if is_potential_nosetest(item):
         if not call_optional(item.obj, "teardown"):
             call_optional(item.parent.obj, "teardown")
@@ -29,11 +30,16 @@ def is_potential_nosetest(item: Item) -> bool:
     )
 
 
-def call_optional(obj, name):
+def call_optional(obj: object, name: str) -> bool:
     method = getattr(obj, name, None)
-    isfixture = hasattr(method, "_pytestfixturefunction")
-    if method is not None and not isfixture and callable(method):
-        # If there's any problems allow the exception to raise rather than
-        # silently ignoring them.
+    if method is None:
+        return False
+    is_fixture = getfixturemarker(method) is not None
+    if is_fixture:
+        return False
+    if not callable(method):
+        return False
+    # If there are any problems allow the exception to raise rather than
+    # silently ignoring it.
     method()
     return True

testing/python/integration.py

@@ -3,6 +3,7 @@ from typing import Any
 import pytest
 from _pytest import runner
 from _pytest._code import getfslineno
+from _pytest.fixtures import getfixturemarker
 from _pytest.pytester import Pytester
 
 
@@ -334,7 +335,8 @@ class TestReRunTests:
 def test_pytestconfig_is_session_scoped() -> None:
     from _pytest.fixtures import pytestconfig
 
-    marker = pytestconfig._pytestfixturefunction  # type: ignore
+    marker = getfixturemarker(pytestconfig)
+    assert marker is not None
     assert marker.scope == "session"