Remove various extras normalization workarounds

src/pip/_internal/req/req_install.py

@@ -51,7 +51,6 @@
     is_installable_dir,
     redact_auth_from_url,
 )
-from pip._internal.utils.packaging import safe_extra
 from pip._internal.utils.subprocess import runner_with_spinner_message
 from pip._internal.utils.temp_dir import TempDirectory, tempdir_kinds
 from pip._internal.utils.unpacking import unpack_file
@@ -272,12 +271,7 @@ def match_markers(self, extras_requested: Optional[Iterable[str]] = None) -> boo
             extras_requested = ("",)
         if self.markers is not None:
             return any(
-                self.markers.evaluate({"extra": extra})
-                # TODO: Remove these two variants when packaging is upgraded to
-                # support the marker comparison logic specified in PEP 685.
-                or self.markers.evaluate({"extra": safe_extra(extra)})
-                or self.markers.evaluate({"extra": canonicalize_name(extra)})
-                for extra in extras_requested
+                self.markers.evaluate({"extra": extra}) for extra in extras_requested
             )
         else:
             return True

src/pip/_internal/resolution/resolvelib/candidates.py

@@ -430,14 +430,6 @@ def __init__(
     ) -> None:
         self.base = base
         self.extras = frozenset(canonicalize_name(e) for e in extras)
-        # If any extras are requested in their non-normalized forms, keep track
-        # of their raw values. This is needed when we look up dependencies
-        # since PEP 685 has not been implemented for marker-matching, and using
-        # the non-normalized extra for lookup ensures the user can select a
-        # non-normalized extra in a package with its non-normalized form.
-        # TODO: Remove this attribute when packaging is upgraded to support the
-        # marker comparison logic specified in PEP 685.
-        self._unnormalized_extras = extras.difference(self.extras)
 
     def __str__(self) -> str:
         name, rest = str(self.base).split(" ", 1)
@@ -523,7 +515,7 @@ def _calculate_valid_requested_extras(self) -> FrozenSet[str]:
         candidate doesn't support. Any unsupported extras are dropped, and each
         cause a warning to be logged here.
         """
-        requested_extras = self.extras.union(self._unnormalized_extras)
+        requested_extras = self.extras
         valid_extras = frozenset(
             extra
             for extra in requested_extras

tests/functional/test_install_extras.py

@@ -152,24 +152,14 @@ def test_install_fails_if_extra_at_end(
         script.scratch_path / "requirements.txt",
         expect_error=True,
     )
-    assert "Extras after version" in result.stderr
+    assert "Invalid requirement: 'requires_simple_extra>=0.1[extra]'" in result.stderr
 
 
 @pytest.mark.parametrize(
     "specified_extra, requested_extra",
     [
         ("Hop_hOp-hoP", "Hop_hOp-hoP"),
-        pytest.param(
-            "Hop_hOp-hoP",
-            "hop-hop-hop",
-            marks=pytest.mark.xfail(
-                reason=(
-                    "matching a normalized extra request against an"
-                    "unnormalized extra in metadata requires PEP 685 support "
-                    "in packaging (see pypa/pip#11445)."
-                ),
-            ),
-        ),
+        ("Hop_hOp-hoP", "hop-hop-hop"),
         ("hop-hop-hop", "Hop_hOp-hoP"),
     ],
 )