config: don't pass the entire Config to `determine_setup()`

Seems better to make the function a bit more pure, and avoids the
circular import.

src/_pytest/config/__init__.py

@@ -1170,7 +1170,7 @@ class Config:
             ns.inifilename,
             ns.file_or_dir + unknown_args,
             rootdir_cmd_arg=ns.rootdir or None,
-            config=self,
+            invocation_dir=self.invocation_params.dir,
         )
         self._rootpath = rootpath
         self._inipath = inipath

src/_pytest/config/findpaths.py

@@ -7,7 +7,6 @@ from typing import List
 from typing import Optional
 from typing import Sequence
 from typing import Tuple
-from typing import TYPE_CHECKING
 from typing import Union
 
 import iniconfig
@@ -17,9 +16,6 @@ from _pytest.outcomes import fail
 from _pytest.pathlib import absolutepath
 from _pytest.pathlib import commonpath
 
-if TYPE_CHECKING:
-    from . import Config
-
 
 def _parse_ini_config(path: Path) -> iniconfig.IniConfig:
     """Parse the given generic '.ini' file using legacy IniConfig parser, returning
@@ -176,8 +172,21 @@ def determine_setup(
     inifile: Optional[str],
     args: Sequence[str],
     rootdir_cmd_arg: Optional[str] = None,
-    config: Optional["Config"] = None,
+    invocation_dir: Optional[Path] = None,
 ) -> Tuple[Path, Optional[Path], Dict[str, Union[str, List[str]]]]:
+    """Determine the rootdir, inifile and ini configuration values from the
+    command line arguments.
+
+    :param inifile:
+        The `--inifile` command line argument, if given.
+    :param args:
+        The free command line arguments.
+    :param rootdir_cmd_arg:
+        The `--rootdir` command line argument, if given.
+    :param invocation_dir:
+        The working directory when pytest was invoked, if known.
+        If not known, the current working directory is used.
+    """
     rootdir = None
     dirs = get_dirs_from_args(args)
     if inifile:
@@ -198,8 +207,8 @@ def determine_setup(
                 if dirs != [ancestor]:
                     rootdir, inipath, inicfg = locate_config(dirs)
                 if rootdir is None:
-                    if config is not None:
+                    if invocation_dir is not None:
-                        cwd = config.invocation_params.dir
+                        cwd = invocation_dir
                     else:
                         cwd = Path.cwd()
                     rootdir = get_common_ancestor([cwd, ancestor])