gh-118814: Fix the TypeVar constructor when name is passed by keyword

Fix _PyArg_UnpackKeywordsWithVararg for the case when argument for positional-or-keyword parameter is passed by keyword. There was only one such case in the stdlib -- the TypeVar constructor.
python · serhiy-storchaka · Aug 7, 2024 · Aug 4, 2024 · Aug 5, 2024 · Aug 4, 2024
commit dc5949efa56b29c7d006ff33621486ac48c191d4
@@ -579,6 +579,55 @@ def test_constructor(self):
         self.assertEqual(T.__name__, "T")
         self.assertEqual(T.__constraints__, ())
         self.assertIs(T.__bound__, None)
+        self.assertIs(T.__default__, typing.NoDefault)
+        self.assertIs(T.__covariant__, False)
+        self.assertIs(T.__contravariant__, False)
+        self.assertIs(T.__infer_variance__, False)
+
+        T = TypeVar(name="T", bound=type)
+        self.assertEqual(T.__name__, "T")
+        self.assertEqual(T.__constraints__, ())
+        self.assertIs(T.__bound__, type)
+        self.assertIs(T.__default__, typing.NoDefault)
+        self.assertIs(T.__covariant__, False)
+        self.assertIs(T.__contravariant__, False)
+        self.assertIs(T.__infer_variance__, False)
+
+        T = TypeVar(name="T", default=())
+        self.assertEqual(T.__name__, "T")
+        self.assertEqual(T.__constraints__, ())
+        self.assertIs(T.__bound__, None)
+        self.assertIs(T.__default__, ())
+        self.assertIs(T.__covariant__, False)
+        self.assertIs(T.__contravariant__, False)
+        self.assertIs(T.__infer_variance__, False)
+
+        T = TypeVar(name="T", covariant=True)
+        self.assertEqual(T.__name__, "T")
+        self.assertEqual(T.__constraints__, ())
+        self.assertIs(T.__bound__, None)
+        self.assertIs(T.__default__, typing.NoDefault)
+        self.assertIs(T.__covariant__, True)
+        self.assertIs(T.__contravariant__, False)
+        self.assertIs(T.__infer_variance__, False)
+
+        T = TypeVar(name="T", contravariant=True)
+        self.assertEqual(T.__name__, "T")
+        self.assertEqual(T.__constraints__, ())
+        self.assertIs(T.__bound__, None)
+        self.assertIs(T.__default__, typing.NoDefault)
+        self.assertIs(T.__covariant__, False)
+        self.assertIs(T.__contravariant__, True)
+        self.assertIs(T.__infer_variance__, False)
+
+        T = TypeVar(name="T", infer_variance=True)
+        self.assertEqual(T.__name__, "T")
+        self.assertEqual(T.__constraints__, ())
+        self.assertIs(T.__bound__, None)
+        self.assertIs(T.__default__, typing.NoDefault)
+        self.assertIs(T.__covariant__, False)
+        self.assertIs(T.__contravariant__, False)
+        self.assertIs(T.__infer_variance__, True)
 
 
 class TypeParameterDefaultsTests(BaseTestCase):

diff --git a/Misc/NEWS.d/next/Library/2024-08-04-14-07-18.gh-issue-118814.uiyks1.rst b/Misc/NEWS.d/next/Library/2024-08-04-14-07-18.gh-issue-118814.uiyks1.rst
@@ -0,0 +1 @@
+Fix the :class:`typing.TypeVar` constructor when name is passed by keyword.
diff --git a/Python/getargs.c b/Python/getargs.c
@@ -2601,7 +2601,7 @@ _PyArg_UnpackKeywordsWithVararg(PyObject *const *args, Py_ssize_t nargs,
          *
          * Otherwise, we leave a place at `buf[vararg]` for vararg tuple
          * so the index is `i + 1`. */
-        if (nargs < vararg && i != vararg) {
+        if (i < vararg) {
             buf[i] = current_arg;
         }
         else {
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Fix the :class:`typing.TypeVar` constructor when name is passed by keyword.