Fix crash when importing ssl after re-initialization

The current METH_FASTCALL|METH_KEYWORDS functions in a non-builtin module can cause segfaults after restarting the main interpreter, invoking _PyArg_UnpackKeywords() with an insufficiently cleared _PyArg_Parser struct. This patch fixes the invalidation of the static argument parsers.
python · kumaraditya303 · Aug 2, 2024 · Jul 30, 2024 · Jul 30, 2024 · Jul 30, 2024
commit 1f4e6da8a347b1f4000188d0c4344cd6a8d532d6
diff --git a/Lib/test/test_embed.py b/Lib/test/test_embed.py
@@ -461,6 +461,25 @@ def add(cls, slot, own):
             self.assertEqual(result, {})
         self.assertEqual(out, '')
 
+    def test_getargs_reset_static_parser(self):
+        # Test _PyArg_Parser initializations via _PyArg_UnpackKeywords()
+        # https://github.com/python/cpython/issues/122334
+        code = textwrap.dedent("""
+            import _ssl
+            _ssl.txt2obj(txt='1.3')
+            print('1')
+
            import _queue
+            _queue.SimpleQueue().put_nowait(item=None)
+            print('2')
+
+            import _zoneinfo
+            _zoneinfo.ZoneInfo.clear_cache(only_keys=['Foo/Bar'])
+            print('3')
+        """)
+        out, err = self.run_embedded_interpreter("test_repeated_init_exec", code)
+        self.assertEqual(out, '1\n2\n3\n' * INIT_LOOPS)
+
 
 @unittest.skipIf(_testinternalcapi is None, "requires _testinternalcapi")
 class InitConfigTests(EmbeddingTestsMixin, unittest.TestCase):

diff --git a/Misc/NEWS.d/next/Library/2024-07-30-21-29-30.gh-issue-122334.LeoE1x.rst b/Misc/NEWS.d/next/Library/2024-07-30-21-29-30.gh-issue-122334.LeoE1x.rst
@@ -0,0 +1 @@
+Fix crash when importing :mod:`ssl` after the main interpreter restarts.
diff --git a/Python/getargs.c b/Python/getargs.c
@@ -2030,6 +2030,19 @@ parser_clear(struct _PyArg_Parser *parser)
     if (parser->is_kwtuple_owned) {
         Py_CLEAR(parser->kwtuple);
     }
+
+    if (parser->format) {
+        parser->fname = NULL;
+    }
+    else {
+        assert(parser->fname != NULL);
+    }
+    parser->custom_msg = NULL;
+    parser->pos = 0;
+    parser->min = 0;
+    parser->max = 0;
+    parser->is_kwtuple_owned = 0;
+    parser->once.v = 0;
 }
 
 static PyObject*