Fix collection of staticmethods defined with functools.partial

Related to #5701

src/_pytest/compat.py

@@ -78,7 +78,7 @@ def num_mock_patch_args(function):
     )
 
 
-def getfuncargnames(function, is_method=False, cls=None):
+def getfuncargnames(function, *, name: str = "", is_method=False, cls=None):
     """Returns the names of a function's mandatory arguments.
 
     This should return the names of all function arguments that:
@@ -91,11 +91,12 @@ def getfuncargnames(function, is_method=False, cls=None):
     be treated as a bound method even though it's not unless, only in
     the case of cls, the function is a static method.
 
+    The name parameter should be the original name in which the function was collected.
+
     @RonnyPfannschmidt: This function should be refactored when we
     revisit fixtures. The fixture mechanism should ask the node for
     the fixture names, and not try to obtain directly from the
     function object well after collection has occurred.
-
     """
     # The parameters attribute of a Signature object contains an
     # ordered mapping of parameter names to Parameter instances.  This
@@ -118,11 +119,14 @@ def getfuncargnames(function, is_method=False, cls=None):
         )
         and p.default is Parameter.empty
     )
+    if not name:
+        name = function.__name__
+
     # If this function should be treated as a bound method even though
     # it's passed as an unbound method or function, remove the first
     # parameter name.
     if is_method or (
-        cls and not isinstance(cls.__dict__.get(function.__name__, None), staticmethod)
+        cls and not isinstance(cls.__dict__.get(name, None), staticmethod)
     ):
         arg_names = arg_names[1:]
     # Remove any names that will be replaced with mocks.
@@ -245,7 +249,7 @@ def get_real_method(obj, holder):
     try:
         is_method = hasattr(obj, "__func__")
         obj = get_real_func(obj)
-    except Exception:
+    except Exception:  # pragma: no cover
         return obj
     if is_method and hasattr(obj, "__get__") and callable(obj.__get__):
         obj = obj.__get__(holder)

src/_pytest/fixtures.py

@@ -828,7 +828,7 @@ class FixtureDef:
             where=baseid,
         )
         self.params = params
-        self.argnames = getfuncargnames(func, is_method=unittest)
+        self.argnames = getfuncargnames(func, name=argname, is_method=unittest)
         self.unittest = unittest
         self.ids = ids
         self._finalizers = []
@@ -1143,7 +1143,7 @@ class FixtureManager:
 
     def getfixtureinfo(self, node, func, cls, funcargs=True):
         if funcargs and not getattr(node, "nofuncargs", False):
-            argnames = getfuncargnames(func, cls=cls)
+            argnames = getfuncargnames(func, name=node.name, cls=cls)
         else:
             argnames = ()