commit ddb536ba7b7c6022424e39d666c3cc81772645c0
author Serhiy Storchaka <storchaka@gmail.com> Fri Sep 08 10:43:54 2017 +0300
committer GitHub <noreply@github.com> Fri Sep 08 10:43:54 2017 +0300
tree 48ba8d3f97ac4b4b060c910db81cf48bb16ba896
parent 9f2b3d4c2899f9caea2e47063061a76e460ac618

[3.6] bpo-31393: Fix the use of PyUnicode_READY(). (GH-3451). (#3453)

(cherry picked from commit e3b2b4b8d9e751b49e3550cb83ba39b54fdc377c)

Python/ceval.c

diff --git a/Python/ceval.c b/Python/ceval.c
index 4aa3250..2b74d0e 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -5307,13 +5307,16 @@
                 PyErr_Clear();
             break;
         }
-        if (skip_leading_underscores &&
-            PyUnicode_Check(name) &&
-            PyUnicode_READY(name) != -1 &&
-            PyUnicode_READ_CHAR(name, 0) == '_')
-        {
-            Py_DECREF(name);
-            continue;
+        if (skip_leading_underscores && PyUnicode_Check(name)) {
+            if (PyUnicode_READY(name) == -1) {
+                Py_DECREF(name);
+                err = -1;
+                break;
+            }
+            if (PyUnicode_READ_CHAR(name, 0) == '_') {
+                Py_DECREF(name);
+                continue;
+            }
         }
         value = PyObject_GetAttr(v, name);
         if (value == NULL)