Fix PyUnicode_Format(): return NULL if PyUnicode_READY(uformat) failed

This error cannot occur in practice: PyUnicode_FromObject() always return
a "ready" string.

diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 0da565a612b33c9741d5d104e5b73e922f3fe6f7..87ac044e1c43b95cbe5995dcbfb1c98e672676fd 100644 (file)
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -13442,8 +13442,10 @@ PyUnicode_Format(PyObject *format, PyObject *args)
     uformat = PyUnicode_FromObject(format);
     if (uformat == NULL)
         return NULL;
-    if (PyUnicode_READY(uformat) == -1)
+    if (PyUnicode_READY(uformat) == -1) {
         Py_DECREF(uformat);
+        return NULL;
+    }
 
     fmt = PyUnicode_DATA(uformat);
     fmtkind = PyUnicode_KIND(uformat);