[Python-checkins] gh-94996: Disallow parsing pos only params with feature_version < (3, 8) (GH-94997)

[miss-islington]

https://github.com/python/cpython/commit/4abf84602f81da6719f761140dc909828350b45c
commit: 4abf84602f81da6719f761140dc909828350b45c
branch: 3.11
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: miss-islington <31488909+miss-islington at users.noreply.github.com>
date: 2022-08-12T10:53:09-07:00
summary:

gh-94996: Disallow parsing pos only params with feature_version < (3, 8) (GH-94997)

(cherry picked from commit b5e3ea286289fcad12be78480daf3756e350f69f)

Co-authored-by: Shantanu <12621235+hauntsaninja at users.noreply.github.com>

files:
A Misc/NEWS.d/next/Core and Builtins/2022-07-19-04-34-56.gh-issue-94996.dV564A.rst
M Grammar/python.gram
M Lib/test/test_ast.py
M Lib/test/test_type_comments.py
M Parser/parser.c

diff --git a/Grammar/python.gram b/Grammar/python.gram
index 6a81e14decbd..afae85d72339 100644
--- a/Grammar/python.gram
+++ b/Grammar/python.gram
@@ -287,9 +287,9 @@ params[arguments_ty]:
 
 parameters[arguments_ty]:
     | a=slash_no_default b[asdl_arg_seq*]=param_no_default* c=param_with_default* d=[star_etc] {
-        _PyPegen_make_arguments(p, a, NULL, b, c, d) }
+        CHECK_VERSION(arguments_ty, 8, "Positional-only parameters are", _PyPegen_make_arguments(p, a, NULL, b, c, d)) }
     | a=slash_with_default b=param_with_default* c=[star_etc] {
-        _PyPegen_make_arguments(p, NULL, a, NULL, b, c) }
+        CHECK_VERSION(arguments_ty, 8, "Positional-only parameters are", _PyPegen_make_arguments(p, NULL, a, NULL, b, c)) }
     | a[asdl_arg_seq*]=param_no_default+ b=param_with_default* c=[star_etc] {
         _PyPegen_make_arguments(p, NULL, NULL, a, b, c) }
     | a=param_with_default+ b=[star_etc] { _PyPegen_make_arguments(p, NULL, NULL, NULL, a, b)}
diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
index 9734218c21be..a52fad834a6f 100644
--- a/Lib/test/test_ast.py
+++ b/Lib/test/test_ast.py
@@ -738,6 +738,14 @@ def test_ast_asdl_signature(self):
         expressions[0] = f"expr = {ast.expr.__subclasses__()[0].__doc__}"
         self.assertCountEqual(ast.expr.__doc__.split("\n"), expressions)
 
+    def test_positional_only_feature_version(self):
+        ast.parse('def foo(x, /): ...', feature_version=(3, 8))
+        ast.parse('def bar(x=1, /): ...', feature_version=(3, 8))
+        with self.assertRaises(SyntaxError):
+            ast.parse('def foo(x, /): ...', feature_version=(3, 7))
+        with self.assertRaises(SyntaxError):
+            ast.parse('def bar(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
@@ -746,7 +754,7 @@ def test_parenthesized_with_feature_version(self):
             ast.parse('with (CtxManager() as example): ...', feature_version=(3, 8))
         ast.parse('with CtxManager() as example: ...', feature_version=(3, 8))
 
-    def test_issue40614_feature_version(self):
+    def test_debug_f_string_feature_version(self):
         ast.parse('f"{x=}"', feature_version=(3, 8))
         with self.assertRaises(SyntaxError):
             ast.parse('f"{x=}"', feature_version=(3, 7))
diff --git a/Lib/test/test_type_comments.py b/Lib/test/test_type_comments.py
index 71d1430dbc93..7a348be6d3f1 100644
--- a/Lib/test/test_type_comments.py
+++ b/Lib/test/test_type_comments.py
@@ -323,7 +323,7 @@ def test_ignores(self):
         self.assertEqual(tree.type_ignores, [])
 
     def test_longargs(self):
-        for tree in self.parse_all(longargs):
+        for tree in self.parse_all(longargs, minver=8):
             for t in tree.body:
                 # The expected args are encoded in the function name
                 todo = set(t.name[1:])
diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-07-19-04-34-56.gh-issue-94996.dV564A.rst b/Misc/NEWS.d/next/Core and Builtins/2022-07-19-04-34-56.gh-issue-94996.dV564A.rst
new file mode 100644
index 000000000000..90c9ada079e0
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-07-19-04-34-56.gh-issue-94996.dV564A.rst	
@@ -0,0 +1 @@
+:func:`ast.parse` will no longer parse function definitions with positional-only params when passed ``feature_version`` less than ``(3, 8)``. Patch by Shantanu Jain.
diff --git a/Parser/parser.c b/Parser/parser.c
index e578fd73ad9b..9f3862f0fc00 100644
--- a/Parser/parser.c
+++ b/Parser/parser.c
@@ -4637,7 +4637,7 @@ parameters_rule(Parser *p)
         )
         {
             D(fprintf(stderr, "%*c+ parameters[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "slash_no_default param_no_default* param_with_default* star_etc?"));
-            _res = _PyPegen_make_arguments ( p , a , NULL , b , c , d );
+            _res = CHECK_VERSION ( arguments_ty , 8 , "Positional-only parameters are" , _PyPegen_make_arguments ( p , a , NULL , b , c , d ) );
             if (_res == NULL && PyErr_Occurred()) {
                 p->error_indicator = 1;
                 p->level--;
@@ -4667,7 +4667,7 @@ parameters_rule(Parser *p)
         )
         {
             D(fprintf(stderr, "%*c+ parameters[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "slash_with_default param_with_default* star_etc?"));
-            _res = _PyPegen_make_arguments ( p , NULL , a , NULL , b , c );
+            _res = CHECK_VERSION ( arguments_ty , 8 , "Positional-only parameters are" , _PyPegen_make_arguments ( p , NULL , a , NULL , b , c ) );
             if (_res == NULL && PyErr_Occurred()) {
                 p->error_indicator = 1;
                 p->level--;