fix: restore previous behavior on platform_release

src/packaging/markers.py

@@ -15,6 +15,7 @@
 from ._tokenizer import ParserSyntaxError
 from .specifiers import InvalidSpecifier, Specifier
 from .utils import canonicalize_name
+from .version import Version
 
 __all__ = [
     "EvaluateContext",
@@ -177,13 +178,16 @@ def _format_marker(
 }
 
 
-def _eval_op(lhs: str, op: Op, rhs: str | AbstractSet[str]) -> bool:
+def _eval_op(lhs: str, op: Op, rhs: str | AbstractSet[str], *, key: str) -> bool:
+    # This is here to avoid a behavior change while the spec is being debated.
     if isinstance(rhs, str):
         try:
             spec = Specifier(f"{op.serialize()}{rhs}")
         except InvalidSpecifier:
             pass
         else:
+            if key == "platform_release":
+                Version(lhs)
             return spec.contains(lhs, prereleases=True)
 
     oper: Operator | None = _operators.get(op.serialize())
@@ -236,7 +240,7 @@ def _evaluate_markers(
                 rhs_value = environment[environment_key]
             assert isinstance(lhs_value, str), "lhs must be a string"
             lhs_value, rhs_value = _normalize(lhs_value, rhs_value, key=environment_key)
-            groups[-1].append(_eval_op(lhs_value, op, rhs_value))
+            groups[-1].append(_eval_op(lhs_value, op, rhs_value, key=environment_key))
         else:
             assert marker in ["and", "or"]
             if marker == "or":

src/packaging/specifiers.py

@@ -198,7 +198,7 @@ class Specifier(BaseSpecifier):
             )
             |
             (?:
-                # All other operators only allow a sub set of what the
+                # All other operators only allow a subset of what the
                 # (non)equality operators do. Specifically they do not allow
                 # local versions to be specified nor do they allow the prefix
                 # matching wild cards.

tests/test_markers.py

@@ -22,6 +22,7 @@
     default_environment,
     format_full_version,
 )
+from packaging.version import InvalidVersion
 
 VARIABLES = [
     "extra",
@@ -308,6 +309,11 @@ def test_environment_with_extra_none(self) -> None:
                 {"os_name": "other", "python_version": "2.7.4"},
                 False,
             ),
+            (
+                "platform_release >= '6'",
+                {"platform_release": "6.1-foobar"},
+                InvalidVersion,
+            ),
             ("extra == 'security'", {"extra": "quux"}, False),
             ("extra == 'security'", {"extra": "security"}, True),
             ("extra == 'SECURITY'", {"extra": "security"}, True),
@@ -321,10 +327,17 @@ def test_environment_with_extra_none(self) -> None:
         ],
     )
     def test_evaluates(
-        self, marker_string: str, environment: dict[str, str] | None, expected: bool
+        self,
+        marker_string: str,
+        environment: dict[str, str] | None,
+        expected: bool | type[Exception],
     ) -> None:
         args = () if environment is None else (environment,)
-        assert Marker(marker_string).evaluate(*args) == expected
+        if isinstance(expected, bool):
+            assert Marker(marker_string).evaluate(*args) == expected
+        else:
+            with pytest.raises(expected):
+                Marker(marker_string).evaluate(*args)
 
     @pytest.mark.parametrize(
         "marker_string",