fix: iter_markers/get_closest_marker returns correct closest MRO marker (#14329)

src/_pytest/fixtures.py

@@ -1841,7 +1841,12 @@ def _getautousenames(self, node: nodes.Node) -> Iterator[str]:
 
     def _getusefixturesnames(self, node: nodes.Item) -> Iterator[str]:
         """Return the names of usefixtures fixtures applicable to node."""
-        for marker_node, mark in node.iter_markers_with_node(name="usefixtures"):
+        # Reverse order (farthest to closest) is more natural for usefixtures,
+        # e.g. want a module-level usefixture to be requested before a class one,
+        # a parent class' before a child's, etc.
+        for marker_node, mark in reversed(
+            list(node.iter_markers_with_node(name="usefixtures"))
+        ):
             if not mark.args:
                 marker_node.warn(
                     PytestWarning(

src/_pytest/nodes.py

@@ -330,6 +330,8 @@ def add_marker(self, marker: str | MarkDecorator, append: bool = True) -> None:
     def iter_markers(self, name: str | None = None) -> Iterator[Mark]:
         """Iterate over all markers of the node.
 
+        The markers are returned from closest to farthest.
+
         :param name: If given, filter the results by the name attribute.
         :returns: An iterator of the markers of the node.
         """
@@ -340,14 +342,25 @@ def iter_markers_with_node(
     ) -> Iterator[tuple[Node, Mark]]:
         """Iterate over all markers of the node.
 
+        The markers are returned from closest to farthest.
+
         :param name: If given, filter the results by the name attribute.
         :returns: An iterator of (node, mark) tuples.
         """
         for node in self.iter_parents():
-            for mark in node.own_markers:
+            for mark in node._iter_own_markers_closest_first():
                 if name is None or getattr(mark, "name", None) == name:
                     yield node, mark
 
+    def _iter_own_markers_closest_first(self) -> Iterable[Mark]:
+        """Yield own markers in closest-first order.
+
+        For most nodes this is just own_markers in order.
+        Overridden by nodes whose own_markers contain markers from
+        multiple levels (e.g. Class nodes with MRO-inherited markers).
+        """
+        return self.own_markers
+
     @overload
     def get_closest_marker(self, name: str) -> Mark | None: ...
 

src/_pytest/python.py

@@ -751,6 +751,28 @@ def from_parent(cls, parent, *, name, obj=None, **kw) -> Self:  # type: ignore[o
         """The public constructor."""
         return super().from_parent(name=name, parent=parent, **kw)
 
+    def _iter_own_markers_closest_first(self) -> Iterator[Mark]:
+        """own_markers stores MRO markers in base-first order
+        (construction order). For closest-first iteration, reverse at the
+        MRO class-group level while preserving decorator order within
+        each class."""
+        from _pytest.mark.structures import normalize_mark_list
+
+        # Walk MRO in natural order (closest first: Child, Parent, ...)
+        # yielding each class's marks in their decorator-stacking order.
+        mro_mark_ids: set[int] = set()
+        for cls in self.obj.__mro__:
+            cls_marks = cls.__dict__.get("pytestmark", [])
+            if not isinstance(cls_marks, list):
+                cls_marks = [cls_marks]
+            for mark in normalize_mark_list(cls_marks):
+                mro_mark_ids.add(id(mark))
+                yield mark
+        # Yield any dynamically added markers (via add_marker) not from MRO.
+        for mark in self.own_markers:
+            if id(mark) not in mro_mark_ids:
+                yield mark
+
     def newinstance(self):
         return self.obj()
 

testing/test_mark.py

@@ -656,6 +656,40 @@ def test_has_inherited(self):
         assert has_inherited_marker.kwargs == {"location": "class"}
         assert has_own.get_closest_marker("missing") is None
 
+    def test_mark_closest_mro(self, pytester: Pytester) -> None:
+        """Marks should be collected from MRO from nearest to furthest (#14329)."""
+        pytester.makepyfile(
+            """
+            import pytest
+
+
+            @pytest.mark.foo(0)
+            class TestParent:
+                def test_only_class(self, request):
+                    assert request.node.get_closest_marker("foo").args[0] == 0
+                    assert [mark.args[0] for mark in request.node.iter_markers("foo")] == [0]
+
+                @pytest.mark.foo(1)
+                def test_function_and_class(self, request):
+                    assert request.node.get_closest_marker("foo").args[0] == 1
+                    assert [mark.args[0] for mark in request.node.iter_markers("foo")] == [1, 0]
+
+
+            @pytest.mark.foo(2)
+            class TestChild(TestParent):
+                def test_only_class(self, request):
+                    assert request.node.get_closest_marker("foo").args[0] == 2
+                    assert [mark.args[0] for mark in request.node.iter_markers("foo")] == [2, 0]
+
+                @pytest.mark.foo(3)
+                def test_function_and_class(self, request):
+                    assert request.node.get_closest_marker("foo").args[0] == 3
+                    assert [mark.args[0] for mark in request.node.iter_markers("foo")] == [3, 2, 0]
+            """
+        )
+        result = pytester.runpytest()
+        result.assert_outcomes(passed=4)
+
     def test_mark_with_wrong_marker(self, pytester: Pytester) -> None:
         reprec = pytester.inline_runsource(
             """
@@ -1133,6 +1167,7 @@ class TestBarClass(BaseTests):
 def test_addmarker_order(pytester) -> None:
     session = mock.Mock()
     session.own_markers = []
+    session._iter_own_markers_closest_first.return_value = session.own_markers
     session.parent = None
     session.nodeid = ""
     session.path = pytester.path