[3.12] gh-115881: Ensure ast.parse() parses conditional context managers even with low feature_version passed (#115920) (#115959)

AlexWaygood · web-flow · commit 53b84e772cac · 2024-02-26T15:45:38.000Z
diff --git a/Grammar/python.gram b/Grammar/python.gram
@@ -392,7 +392,7 @@ for_stmt[stmt_ty]:
 with_stmt[stmt_ty]:
     | invalid_with_stmt_indent
     | 'with' '(' a[asdl_withitem_seq*]=','.with_item+ ','? ')' ':' b=block {
-        CHECK_VERSION(stmt_ty, 9, "Parenthesized context managers are", _PyAST_With(a, b, NULL, EXTRA)) }
+        _PyAST_With(a, b, NULL, EXTRA) }
     | 'with' a[asdl_withitem_seq*]=','.with_item+ ':' tc=[TYPE_COMMENT] b=block {
         _PyAST_With(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA) }
     | ASYNC 'with' '(' a[asdl_withitem_seq*]=','.with_item+ ','? ')' ':' b=block {
diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
@@ -1007,19 +1007,15 @@ def test_positional_only_feature_version(self):
         with self.assertRaises(SyntaxError):
             ast.parse('lambda x=1, /: ...', feature_version=(3, 7))
 
-    def test_parenthesized_with_feature_version(self):
-        ast.parse('with (CtxManager() as example): ...', feature_version=(3, 10))
-        # While advertised as a feature in Python 3.10, this was allowed starting 3.9
-        ast.parse('with (CtxManager() as example): ...', feature_version=(3, 9))
-        with self.assertRaises(SyntaxError):
-            ast.parse('with (CtxManager() as example): ...', feature_version=(3, 8))
-        ast.parse('with CtxManager() as example: ...', feature_version=(3, 8))
-
     def test_assignment_expression_feature_version(self):
         ast.parse('(x := 0)', feature_version=(3, 8))
         with self.assertRaises(SyntaxError):
             ast.parse('(x := 0)', feature_version=(3, 7))
 
+    def test_conditional_context_managers_parse_with_low_feature_version(self):
+        # regression test for gh-115881
+        ast.parse('with (x() if y else z()): ...', feature_version=(3, 8))
+
     def test_exception_groups_feature_version(self):
         code = dedent('''
         try: ...
diff --git a/Misc/NEWS.d/next/Library/2024-02-25-19-20-05.gh-issue-115881.ro_Kuw.rst b/Misc/NEWS.d/next/Library/2024-02-25-19-20-05.gh-issue-115881.ro_Kuw.rst
@@ -0,0 +1,4 @@
+Fix issue where :func:`ast.parse` would incorrectly flag conditional context
+managers (such as ``with (x() if y else z()): ...``) as invalid syntax if
+``feature_version=(3, 8)`` was passed. This reverts changes to the
+grammar made as part of gh-94949.
diff --git a/Parser/parser.c b/Parser/parser.c
