`pytest.mark.skipif` silently ignores extra keyword args

[The-Compiler]

In a recent pytest training, a participant mistakenly added strict=True to a skipif marker in a file instead of the xfail one, and that was surprised that nothing happened. Indeed, pytest is happy with:

import pytest

@pytest.mark.skipif(True, strict=True, reason="")
def test_x():
    pass

while pytest.mark.skip does validate the arguments:

@pytest.mark.skip(strict=True, reason="")
def test_y():
    pass

[...]
.venv/lib/python3.14/site-packages/_pytest/skipping.py:249: in pytest_runtest_setup
    skipped = evaluate_skip_marks(item)
              ^^^^^^^^^^^^^^^^^^^^^^^^^
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

item = <Function test_y>

    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"):
            if "condition" not in mark.kwargs:
                conditions = mark.args
            else:
                conditions = (mark.kwargs["condition"],)
    
            # Unconditional.
            if not conditions:
                reason = mark.kwargs.get("reason", "")
                return Skip(reason)
    
            # If any of the conditions are true.
            for condition in conditions:
                result, reason = evaluate_condition(item, mark, condition)
                if result:
                    return Skip(reason)
    
        for mark in item.iter_markers(name="skip"):
            try:
                return Skip(*mark.args, **mark.kwargs)
            except TypeError as e:
>               raise TypeError(str(e) + " - maybe you meant pytest.mark.skipif?") from None
E               TypeError: Skip.__init__() got an unexpected keyword argument 'strict' - maybe you meant pytest.mark.skipif?

.venv/lib/python3.14/site-packages/_pytest/skipping.py:192: TypeError

[mathew1046]

Thanks for the detailed report, @The-Compiler. I'd like to work on this.

The core cause, as I understand it: in evaluate_skip_marks (src/_pytest/skipping.py), the skipif branch only reads condition and reason from mark.kwargs and silently drops any other keyword argument — unlike skip, which passes its kwargs through Skip() so an unknown kwarg raises the helpful "maybe you meant pytest.mark.skipif?" TypeError.

I'm planning to add validation to the skipif branch so an unexpected keyword arg (e.g. strict) raises a clear error instead of being silently ignored, plus a regression test in testing/test_skipping.py. I'll open a PR once it's ready.

[vibecoder666-max]

Thanks for the detailed report, @The-Compiler. I'd like to work on this.

The core cause, as I understand it: in evaluate_skip_marks (src/_pytest/skipping.py), the skipif branch only reads condition and reason from mark.kwargs and silently drops any other keyword argument — unlike skip, which passes its kwargs through Skip() so an unknown kwarg raises the helpful "maybe you meant pytest.mark.skipif?" TypeError.

I'm planning to add validation to the skipif branch so an unexpected keyword arg (e.g. strict) raises a clear error instead of being silently ignored, plus a regression test in testing/test_skipping.py. I'll open a PR once it's ready.

Larp