Prohibit pytest.mark.usefixtures in pytest.param (#12828)

Mitigates #4112 a bit.

Co-authored-by: Bruno Oliveira <[email protected]>

Author: Hawk777

AUTHORS

@@ -95,6 +95,7 @@ Christine Mecklenborg
 Christoph Buelter
 Christopher Dignam
 Christopher Gilling
+Christopher Head
 Claire Cecil
 Claudio Madotto
 Clément M.T. Robert

changelog/4112.improvement.rst

@@ -0,0 +1 @@
+Using :ref:`pytest.mark.usefixtures <pytest.mark.usefixtures ref>` on :func:`pytest.param` now produces an error instead of silently doing nothing.

src/_pytest/mark/__init__.py

@@ -66,7 +66,12 @@ def test_eval(test_input, expected):
             assert eval(test_input) == expected
 
     :param values: Variable args of the values of the parameter set, in order.
-    :param marks: A single mark or a list of marks to be applied to this parameter set.
+
+    :param marks:
+        A single mark or a list of marks to be applied to this parameter set.
+
+        :ref:`pytest.mark.usefixtures <pytest.mark.usefixtures ref>` cannot be added via this parameter.
+
     :param id: The id to attribute to this parameter set.
     """
     return ParameterSet.param(*values, marks=marks, id=id)

src/_pytest/mark/structures.py

@@ -88,6 +88,11 @@ def param(
             marks = (marks,)
         else:
             assert isinstance(marks, collections.abc.Collection)
+        if any(i.name == "usefixtures" for i in marks):
+            raise ValueError(
+                "pytest.param cannot add pytest.mark.usefixtures; see "
+                "https://docs.pytest.org/en/stable/reference/reference.html#pytest-param"
+            )
 
         if id is not None:
             if not isinstance(id, str):

testing/python/integration.py

@@ -407,6 +407,23 @@ def test_params(a, b):
         res = pytester.runpytest("--collect-only")
         res.stdout.fnmatch_lines(["*spam-2*", "*ham-2*"])
 
+    def test_param_rejects_usefixtures(self, pytester: Pytester) -> None:
+        pytester.makepyfile(
+            """
+            import pytest
+
+            @pytest.mark.parametrize("x", [
+                pytest.param(1, marks=[pytest.mark.usefixtures("foo")]),
+            ])
+            def test_foo(x):
+                pass
+        """
+        )
+        res = pytester.runpytest("--collect-only")
+        res.stdout.fnmatch_lines(
+            ["*test_param_rejects_usefixtures.py:4*", "*pytest.param(*"]
+        )
+
 
 def test_function_instance(pytester: Pytester) -> None:
     items = pytester.getitems(