Bug in _pytest.compat.getfuncargnames() corrupts fixture handling for test methods w/ positional-only self parameter

a detailed description of the bug or problem you are having
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Isn't related to specific Pytest versions [ ] pytest and operating system versions
minimal example if possible

Basic example

Passing:

import pytest

@pytest.fixture
def value_fixture():
    return 'value'

class TestClass:

    def test_value(self, value_fixture):
        assert value_fixture == 'value'

Failing:

import pytest


@pytest.fixture
def value_fixture():
    return 'value'


class TestClass:

    def test_value(self, /, value_fixture):
        assert value_fixture == 'value'

Result:

pyfuncitem = <Function test_value>

    @hookimpl(trylast=True)
    def pytest_pyfunc_call(pyfuncitem: Function) -> object | None:
        testfunction = pyfuncitem.obj
        if is_async_function(testfunction):
            async_fail(pyfuncitem.nodeid)
        funcargs = pyfuncitem.funcargs
        testargs = {arg: funcargs[arg] for arg in pyfuncitem._fixtureinfo.argnames}
>       result = testfunction(**testargs)
                 ^^^^^^^^^^^^^^^^^^^^^^^^
E       TypeError: TestClass.test_value() missing 1 required positional argument: 'value_fixture'

Reason

_pytest.compat.getfuncargnames() collects keyword-callable parameters as fixture-receiving arguments:

pytest/src/_pytest/compat.py

Lines 134 to 142 in 103b2b6

    
           arg_names = tuple( 
        
               p.name 
        
               for p in parameters.values() 
        
               if ( 
        
                   p.kind is Parameter.POSITIONAL_OR_KEYWORD 
        
                   or p.kind is Parameter.KEYWORD_ONLY 
        
               ) 
        
               and p.default is Parameter.empty 
        
           )

Then it removes the first one – supposedly 'self' – if given function is a non-static method:

pytest/src/_pytest/compat.py

Lines 149 to 157 in 103b2b6

    
           if ( 
        
               # Not using `getattr` because we don't want to resolve the staticmethod. 
        
               # Not using `cls.__dict__` because we want to check the entire MRO. 
        
               cls 
        
               and not isinstance( 
        
                   inspect.getattr_static(cls, name, default=None), staticmethod 
        
               ) 
        
           ): 
        
               arg_names = arg_names[1:]

Yet, if 'self' is defined as positional only, it wasn't contained in arg_names before removal ...

Fix parameter handling of non-static test methods

Fix handling of positional-only parameters in test methods (pytest-de…

Fix handling of positional-only parameters in test methods (#13377) (#…

Fix handling of positional-only parameters in test methods (pytest-de…

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Bug in _pytest.compat.getfuncargnames() corrupts fixture handling for test methods w/ positional-only self parameter #13376

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	arg_names = tuple(
	p.name
	for p in parameters.values()
	if (
	p.kind is Parameter.POSITIONAL_OR_KEYWORD
	or p.kind is Parameter.KEYWORD_ONLY
	)
	and p.default is Parameter.empty
	)

	if (
	# Not using `getattr` because we don't want to resolve the staticmethod.
	# Not using `cls.__dict__` because we want to check the entire MRO.
	cls
	and not isinstance(
	inspect.getattr_static(cls, name, default=None), staticmethod
	)
	):
	arg_names = arg_names[1:]

Bug in _pytest.compat.getfuncargnames() corrupts fixture handling for test methods w/ positional-only self parameter #13376

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