ensure .keywords is always a dict

Lib/test/test_functools.py

@@ -89,9 +89,11 @@ class TestPartial(unittest.TestCase):
         # exercise special code paths for no keyword args in
         # either the partial object or the caller
         p = self.thetype(capture)
+        self.assertEqual(p.keywords, {})
         self.assertEqual(p(), ((), {}))
         self.assertEqual(p(a=1), ((), {'a':1}))
         p = self.thetype(capture, a=1)
+        self.assertEqual(p.keywords, {'a':1})
         self.assertEqual(p(), ((), {'a':1}))
         self.assertEqual(p(b=2), ((), {'a':1, 'b':2}))
         # keyword args in the call override those in the partial object

Misc/NEWS

@@ -27,6 +27,8 @@ Core and Builtins
 Library
 -------
 
+- The keywords attribute of functools.partial is now always a dictionary.
+
 - Issue #24134: assertRaises() and assertRaisesRegexp() checks are not longer
   successful if the callable is None.
 

Modules/_functoolsmodule.c

@@ -132,16 +132,12 @@ partial_new(PyTypeObject *type, PyObject *args, PyObject *kw)
         Py_DECREF(pto);
         return NULL;
     }
-    if (kw != NULL) {
-        pto->kw = PyDict_Copy(kw);
+    pto->kw = (kw != NULL) ? PyDict_Copy(kw) : PyDict_New();
     if (pto->kw == NULL) {
         Py_DECREF(pto);
         return NULL;
     }
-    } else {
-        pto->kw = Py_None;
-        Py_INCREF(Py_None);
-    }
+
 
     pto->weakreflist = NULL;
     pto->dict = NULL;