Fix fixture visibility with doctest module collection

changelog/14533.bugfix.rst

@@ -0,0 +1 @@
+Fixed a regression where enabling :option:`--doctest-modules` could make fixtures defined in a Python module unavailable to normal tests collected from the same module.

src/_pytest/fixtures.py

@@ -1676,7 +1676,7 @@ def __init__(self, session: Session) -> None:
         # TODO: The order of the FixtureDefs list of each arg is significant,
         #       explain.
         self._arg2fixturedefs: Final[dict[str, list[FixtureDef[Any]]]] = {}
-        self._holderobjseen: Final[set[object]] = set()
+        self._holderobjseen: Final[set[tuple[object, nodes.Node | str | None]]] = set()
         # A mapping from a node to a list of autouse fixture names it defines.
         # The Session entry holds global usefixtures from config.
         self._node_autousenames: Final[dict[nodes.Node, list[str]]] = {
@@ -2031,7 +2031,10 @@ def parsefactories(
             assert isinstance(node_or_obj, nodes.Node)
             holderobj = cast(object, node_or_obj.obj)  # type: ignore[attr-defined]
             effective_node = node_or_obj
-        if holderobj in self._holderobjseen:
+        # The same holder may be parsed with different visibility scopes, e.g.
+        # a module collected as both DoctestModule and Module.
+        holderobj_key = (holderobj, effective_node or effective_nodeid)
+        if holderobj_key in self._holderobjseen:
             return
 
         # Avoid accessing `@property` (and other descriptors) when iterating fixtures.
@@ -2040,7 +2043,7 @@ def parsefactories(
         else:
             holderobj_tp = holderobj
 
-        self._holderobjseen.add(holderobj)
+        self._holderobjseen.add(holderobj_key)
         for name in dir(holderobj):
             # The attribute can be an arbitrary descriptor, so the attribute
             # access below can raise. safe_getattr() ignores such exceptions.

testing/test_doctest.py

@@ -600,6 +600,24 @@ def test_doctestmodule_with_fixtures(self, pytester: Pytester):
         reprec = pytester.inline_run(p, "--doctest-modules")
         reprec.assertoutcome(passed=1)
 
+    def test_doctestmodule_does_not_hide_module_fixtures(
+        self, pytester: Pytester
+    ) -> None:
+        pytester.makepyfile(
+            """
+            import pytest
+
+            @pytest.fixture
+            def foo_fixture():
+                return 1
+
+            def test_foo(foo_fixture):
+                assert foo_fixture
+        """
+        )
+        result = pytester.runpytest("--doctest-modules")
+        result.assert_outcomes(passed=1)
+
     def test_doctestmodule_three_tests(self, pytester: Pytester):
         p = pytester.makepyfile(
             """