fix: validate keyword arguments for pytest.mark.skipif (#14839)

AUTHORS

@@ -475,6 +475,7 @@ Tarcisio Fischer
 Tareq Alayan
 Tatiana Ovary
 Ted Xiao
+The-Habib
 Terje Runde
 Thomas Grainger
 Thomas Hisch

changelog/14839.bugfix.rst

@@ -0,0 +1 @@
+:func:`pytest.mark.skipif` now validates its keyword arguments and raises a :xcp:`TypeError` when unexpected keyword arguments (such as ``strict``) are passed.

src/_pytest/skipping.py

@@ -169,6 +169,14 @@ class Skip:
 def evaluate_skip_marks(item: Item) -> Skip | None:
     """Evaluate skip and skipif marks on item, returning Skip if triggered."""
     for mark in item.iter_markers(name="skipif"):
+        unexpected_kwargs = set(mark.kwargs) - {"condition", "reason"}
+        if unexpected_kwargs:
+            unexpected = sorted(unexpected_kwargs)[0]
+            msg = f"skipif() got an unexpected keyword argument {unexpected!r}"
+            if unexpected == "strict":
+                msg += " - maybe you meant pytest.mark.xfail?"
+            raise TypeError(msg)
+
         if "condition" not in mark.kwargs:
             conditions = mark.args
         else:

testing/test_skipping.py

@@ -61,7 +61,7 @@ def test_marked_one_arg_with_reason(self, pytester: Pytester) -> None:
         item = pytester.getitem(
             """
             import pytest
-            @pytest.mark.skipif("hasattr(os, 'sep')", attr=2, reason="hello world")
+            @pytest.mark.skipif("hasattr(os, 'sep')", reason="hello world")
             def test_func():
                 pass
         """
@@ -70,6 +70,35 @@ def test_func():
         assert skipped
         assert skipped.reason == "hello world"
 
+    def test_marked_skipif_unexpected_kwarg(self, pytester: Pytester) -> None:
+        item = pytester.getitem(
+            """
+            import pytest
+            @pytest.mark.skipif("hasattr(os, 'sep')", invalid=123, reason="hello world")
+            def test_func():
+                pass
+        """
+        )
+        with pytest.raises(
+            TypeError, match=r"skipif\(\) got an unexpected keyword argument 'invalid'"
+        ):
+            evaluate_skip_marks(item)
+
+    def test_marked_skipif_strict_kwarg(self, pytester: Pytester) -> None:
+        item = pytester.getitem(
+            """
+            import pytest
+            @pytest.mark.skipif(True, strict=True, reason="hello world")
+            def test_func():
+                pass
+        """
+        )
+        with pytest.raises(
+            TypeError,
+            match=r"skipif\(\) got an unexpected keyword argument 'strict' - maybe you meant pytest.mark.xfail\?",
+        ):
+            evaluate_skip_marks(item)
+
     def test_marked_one_arg_twice(self, pytester: Pytester) -> None:
         lines = [
             """@pytest.mark.skipif("not hasattr(os, 'murks')")""",