Check error when calling PyUnicode_AppendAndDel()

Modules/_ctypes/callproc.c

@@ -944,9 +944,9 @@ void _ctypes_extend_error(PyObject *exc_class, char *fmt, ...)
     else {
         PyErr_Clear();
         PyUnicode_AppendAndDel(&s, PyUnicode_FromString("???"));
-        if (s == NULL)
-            goto error;
     }
+    if (s == NULL)
+        goto error;
     PyErr_SetObject(exc_class, s);
 error:
     Py_XDECREF(tp);

Python/dynload_win.c

@@ -187,7 +187,7 @@ dl_funcptr _PyImport_GetDynLoadWindows(const char *shortname,
         HINSTANCE hDLL = NULL;
         unsigned int old_mode;
         ULONG_PTR cookie = 0;
-        
+
         /* Don't display a message box when Python can't load a DLL */
         old_mode = SetErrorMode(SEM_FAILCRITICALERRORS);
 
@@ -248,8 +248,10 @@ dl_funcptr _PyImport_GetDynLoadWindows(const char *shortname,
                         theInfo,
                         theLength));
             }
-            PyErr_SetObject(PyExc_ImportError, message);
-            Py_XDECREF(message);
+            if (message != NULL) {
+                PyErr_SetObject(PyExc_ImportError, message);
+                Py_DECREF(message);
+            }
             return NULL;
         } else {
             char buffer[256];