config: use intermixed arg parsing also in parse_known_and_unknown_args

Missed in fc2d649; we should be
consistent here.

Author: bluetech

src/_pytest/config/argparsing.py

@@ -6,6 +6,7 @@
 from collections.abc import Mapping
 from collections.abc import Sequence
 import os
+import sys
 from typing import Any
 from typing import final
 from typing import Literal
@@ -164,7 +165,17 @@ def parse_known_and_unknown_args(
         """
         optparser = self._getparser()
         strargs = [os.fspath(x) for x in args]
-        return optparser.parse_known_args(strargs, namespace=namespace)
+        if sys.version_info < (3, 12):
+            # Older argparse have a bugged parse_known_intermixed_args.
+            namespace, unknown = self.optparser.parse_known_args(strargs, namespace)
+            assert namespace is not None
+            file_or_dir = getattr(namespace, FILE_OR_DIR)
+            unknown_flags: list[str] = []
+            for arg in unknown:
+                (unknown_flags if arg.startswith("-") else file_or_dir).append(arg)
+            return namespace, unknown_flags
+        else:
+            return optparser.parse_known_intermixed_args(strargs, namespace)
 
     def addini(
         self,

testing/test_parseopt.py

@@ -142,17 +142,17 @@ def test_parse_known_args(self, parser: parseopt.Parser) -> None:
         parser.parse_known_args([Path(".")])
         parser.addoption("--hello", action="store_true")
         ns = parser.parse_known_args(["x", "--y", "--hello", "this"])
-        assert ns.hello
-        assert ns.file_or_dir == ["x"]
+        assert ns.hello is True
+        assert ns.file_or_dir == ["x", "this"]
 
     def test_parse_known_and_unknown_args(self, parser: parseopt.Parser) -> None:
         parser.addoption("--hello", action="store_true")
         ns, unknown = parser.parse_known_and_unknown_args(
             ["x", "--y", "--hello", "this"]
         )
-        assert ns.hello
-        assert ns.file_or_dir == ["x"]
-        assert unknown == ["--y", "this"]
+        assert ns.hello is True
+        assert ns.file_or_dir == ["x", "this"]
+        assert unknown == ["--y"]
 
     def test_parse_will_set_default(self, parser: parseopt.Parser) -> None:
         parser.addoption("--hello", dest="hello", default="x", action="store")