Issue #26282: PyArg_ParseTupleAndKeywords() and Argument Clinic now support

positional-only and keyword parameters in the same function.

Lib/test/test_capi.py

@@ -527,6 +527,31 @@ class SkipitemTest(unittest.TestCase):
         self.assertRaises(ValueError, _testcapi.parse_tuple_and_keywords,
                           (), {}, b'', [42])
 
+    def test_positional_only(self):
+        parse = _testcapi.parse_tuple_and_keywords
+
+        parse((1, 2, 3), {}, b'OOO', ['', '', 'a'])
+        parse((1, 2), {'a': 3}, b'OOO', ['', '', 'a'])
+        with self.assertRaisesRegex(TypeError,
+                'Function takes at least 2 positional arguments \(1 given\)'):
+            parse((1,), {'a': 3}, b'OOO', ['', '', 'a'])
+        parse((1,), {}, b'O|OO', ['', '', 'a'])
+        with self.assertRaisesRegex(TypeError,
+                'Function takes at least 1 positional arguments \(0 given\)'):
+            parse((), {}, b'O|OO', ['', '', 'a'])
+        parse((1, 2), {'a': 3}, b'OO$O', ['', '', 'a'])
+        with self.assertRaisesRegex(TypeError,
+                'Function takes exactly 2 positional arguments \(1 given\)'):
+            parse((1,), {'a': 3}, b'OO$O', ['', '', 'a'])
+        parse((1,), {}, b'O|O$O', ['', '', 'a'])
+        with self.assertRaisesRegex(TypeError,
+                'Function takes at least 1 positional arguments \(0 given\)'):
+            parse((), {}, b'O|O$O', ['', '', 'a'])
+        with self.assertRaisesRegex(SystemError, 'Empty parameter name after \$'):
+            parse((1,), {}, b'O|$OO', ['', '', 'a'])
+        with self.assertRaisesRegex(SystemError, 'Empty keyword'):
+            parse((1,), {}, b'O|OO', ['', 'a', ''])
+
 
 @unittest.skipUnless(threading, 'Threading required for this test.')
 class TestThreadState(unittest.TestCase):

Lib/test/test_getargs2.py

@@ -658,6 +658,39 @@ class KeywordOnly_TestCase(unittest.TestCase):
             getargs_keyword_only(1, 2, **{'\uDC80': 10})
 
 
+class PositionalOnlyAndKeywords_TestCase(unittest.TestCase):
+    from _testcapi import getargs_positional_only_and_keywords as getargs
+
+    def test_positional_args(self):
+        # using all possible positional args
+        self.assertEqual(self.getargs(1, 2, 3), (1, 2, 3))
+
+    def test_mixed_args(self):
+        # positional and keyword args
+        self.assertEqual(self.getargs(1, 2, keyword=3), (1, 2, 3))
+
+    def test_optional_args(self):
+        # missing optional args
+        self.assertEqual(self.getargs(1, 2), (1, 2, -1))
+        self.assertEqual(self.getargs(1, keyword=3), (1, -1, 3))
+
+    def test_required_args(self):
+        self.assertEqual(self.getargs(1), (1, -1, -1))
+        # required positional arg missing
+        with self.assertRaisesRegex(TypeError,
+            "Function takes at least 1 positional arguments \(0 given\)"):
+            self.getargs()
+
+        with self.assertRaisesRegex(TypeError,
+            "Function takes at least 1 positional arguments \(0 given\)"):
+            self.getargs(keyword=3)
+
+    def test_empty_keyword(self):
+        with self.assertRaisesRegex(TypeError,
+            "'' is an invalid keyword argument for this function"):
+            self.getargs(1, 2, **{'': 666})
+
+
 class Bytes_TestCase(unittest.TestCase):
     def test_c(self):
         from _testcapi import getargs_c